KR100802670B1 - Electrostatic absorption apparatus, plasma processing apparatus and plasma processing method - Google Patents

Abstract

The present invention is to stably and reliably adsorb and hold the substrate of the insulator without causing abnormal discharge or dielectric breakdown. The mounting table 10 on which the insulating substrate G is mounted includes a rectangular block-shaped susceptor 14 made of a conductor such as aluminum on the base member 12, an insulator surrounding the susceptor 14, For example, a rectangular frame-shaped focus ring 16 made of quartz is provided, and the lower dielectric layer 18, the electrode layer 20, and the upper dielectric layer 22 are formed on the main surface (upper surface) of the susceptor 14 by thermal spraying, respectively. The electrostatic adsorption part 24 which consists of an upper layer structure of () is provided. The lower dielectric layer 18 and the upper dielectric layer 22 are made of ceramics of alumina (Al ₂ O ₃ ) and zirconia (ZrO ₂ ) having a volume resistivity of 1 × 10 ¹⁴ Ω · cm or more. The output terminal of the direct current (DC) current 34 is electrically connected to the electrode layer 20.

Description

Electrostatic adsorption apparatus, plasma processing apparatus, and plasma processing method {ELECTROSTATIC ABSORPTION APPARATUS, PLASMA PROCESSING APPARATUS AND PLASMA PROCESSING METHOD}             

1 is a schematic cross-sectional view showing the configuration of an electrostatic adsorption device in a first embodiment of the present invention;

2 is a schematic plan view showing the configuration of main parts of a mounting table in the electrostatic adsorption device of the embodiment;

3 is a schematic sectional view of an electrostatic adsorption device in a second embodiment,

4 is a schematic sectional view of an electrostatic adsorption device in a third embodiment,

5 is a diagram schematically showing a change in susceptor potential when DC voltage is applied in the electrostatic adsorption apparatus of the present invention;

6 is a schematic sectional view showing a configuration of a plasma processing apparatus in a fourth embodiment;

7 is a graph of an experimental example showing the substrate cooling effect of He gas in the electrostatic adsorption apparatus of the present invention;

8 is a graph showing a relationship between adsorption force and applied voltage in the electrostatic adsorption device of the present invention;

9 is a graph for showing a preferable film thickness of a dielectric layer used in the electrostatic adsorption apparatus of the present invention;

10 is a circuit diagram showing an equivalent circuit of the principal part of the plasma processing apparatus of the embodiment;

11 is a time sequence showing an operation sequence in the plasma processing apparatus of the embodiment;

12 is a schematic sectional view showing a configuration of a plasma processing apparatus according to a second embodiment;

13 is a schematic cross-sectional view showing a configuration of an electrostatic adsorption device of a conventional example;

14 is a schematic cross-sectional view showing a configuration of another electrostatic attraction device of the related art.

Explanation of symbols for the main parts of the drawings

G: Glass Insulated Substrate 10: Mounting Table

12: base member 14: susceptor

16: focus ring 18: lower dielectric layer

20: electrode layer 22: upper dielectric layer

24: electrostatic adsorption portion 26: refrigerant flow path

30: matching device 32: high frequency power

The present invention relates to an electrostatic adsorption device for electrostatically fixing and fixing a substrate to be processed made of an insulator, a plasma processing device and a plasma processing method using the same.

In manufacturing a panel of a flat panel display (FPD), a device of a pixel, an electrode, a wiring, or the like is generally formed on a substrate by an insulator such as glass. Plasma is used in various processes of panel manufacturing in microfabrication such as etching, chemical vapor deposition (CVD), ashing, sputtering, and the like. In the manufacturing apparatus which performs such a plasma process, a board | substrate is mounted in a mounting object in a pressure reduction process container, and the upper surface (processed surface) of a board | substrate is exposed to the plasma of a process gas, and a processing process is performed. In this case, the temperature rise due to the heat generation during the plasma treatment is suppressed to perform the processing. In this case, it is necessary to suppress the temperature rise due to the heat generation during the plasma treatment and to constantly suppress the temperature of the substrate. Therefore, the refrigerant regulated by the cooling device is circulated and supplied to the refrigerant passage in the mounting table. Background Art A method of indirectly cooling a substrate by passing a gas having good heat transfer property into a mounting mass and supplying it to the back surface of the substrate is well used. This cooling method requires a mechanism for fixing and holding the substrate to the mounting object against the supply pressure of the He gas.

FIG. 13 shows a configuration of a conventional electrostatic adsorption apparatus for holding a substrate of an insulator by an electrostatic attraction force in a plasma processing apparatus. In this electrostatic adsorption device, the mounting table 200 is provided with a susceptor 204 made of a conductor and a focus ring 206 made of an insulator on the base member 202. The insulating substrate G is mounted on the upper surface of the susceptor 204 so that the end portion of the substrate is covered with the upper surface of the focus ring 206. The coolant passage 208 is provided inside the susceptor 204, and the coolant from the cooling device (not shown) flows through the coolant flow path 208. In addition, a plurality of through holes 210 are provided on the upper surface of the susceptor 204, and the He gas for heat transfer from the He gas supply unit (not shown) is connected to the substrate G through the through holes 210. The back surface is supplied at a predetermined pressure.

A high frequency of several MHz to several tens of MHz is applied to the susceptor 204 from the high frequency power supply 212. The plasma PZ of the processing gas is generated on the substrate G during the plasma processing. This plasma PZ is also generated by the high frequency from the high frequency power supply 212. In the latter case, the high frequency applied from the high frequency power supply 212 to the susceptor 204 is used for the bias for drawing ions in the plasma PZ into the target surface of the substrate G.

The susceptor 204 is supplied with a DC voltage of about several kV by the DC (direct current) power supply 214. When the DC voltage is a positive voltage, negative charges (electrons and anions) in the plasma PZ are attracted to and accumulated on the upper surface (processed surface) of the substrate G, whereby the negative surface of the upper surface of the substrate G is obtained. An electrostatic force (coulomb force) attracts each other between the charge and the susceptor 204, and the electrostatic attraction forces the substrate G to be attracted and fixed on the susceptor 204.

Fig. 14 shows a prior art in which the electrostatic adsorption device (Fig. 13) is improved. In this electrostatic adsorption apparatus, the upper surface of the susceptor 204 is covered with an insulator layer 216. The through hole 210 is formed through the upper surface portion of the susceptor 204 and the insulator layer 216 from the gas flow path inside the susceptor 204.

 Insulating substrates for FPDs have recently become increasingly demanded in size. In the electrostatic adsorption apparatus as described above, the larger the size of the insulating substrate, the more likely the substrate is bent due to thermal stress, so the supply pressure of the heat transfer gas (He gas) used to control the substrate temperature must be increased. Along with this, it is necessary to increase the electrostatic adsorption force for holding the substrate fixed. However, when the DC voltage which applies a voltage to a susceptor is made high in order to increase electrostatic attraction force, there exists a problem that breakage, such as abnormal discharge (almost arc discharge) and insulation breakdown, becomes easy to occur.

In fact, in the conventional example of FIG. 13, when the insulating substrate G is enlarged, the susceptor 204 is increased by increasing the DC voltage applied from the DC power supply 214 to the susceptor 204 in order to increase the electrostatic attraction force. Abnormal discharge easily occurs between the peripheral edge of the upper surface and the plasma PZ, and breakage of the susceptor 204 (electrode destruction) easily occurs. In this regard, in the conventional example of FIG. 14, the above abnormal discharge can be controlled to some extent by the insulator layer 216. However, there is a fear that abnormal discharge may still occur from the gap between the susceptor 204 and the focus ring 206, the susceptor 204, or the like exposed in the through hole 210. In addition, when the temperature of the susceptor 204 is raised, a large thermal stress is applied to the insulator layer 216 due to the difference in the expansion ratio of the susceptor 204 and the insulator layer 216, and the insulator layer 216 is cracked. This tends to occur. Such cracking tends to occur as the substrate size increases (generally, when the substrate longest dimension becomes 500 mm or more).

In addition, poor adsorption of the substrate G on the mounting table 200, end defects, or misalignment of the substrate (conveyance misalignment) also cause abnormal discharge. However, there has been no effective solution to this problem in the prior art. In this way, if the DC voltage is increased, abnormal discharge, dielectric breakdown, etc. are likely to occur, making it difficult to increase the electrostatic adsorption force, thereby making it difficult to perform in-plane uniform temperature control on the large substrate. In-plane uniform plasma processing becomes difficult to perform.

SUMMARY OF THE INVENTION The present invention has been made in view of the problems of the prior art as described above, and an object thereof is to provide a highly reliable electrostatic adsorption device capable of increasing the holding force on an insulating substrate without causing abnormal discharge or dielectric breakdown. .

Another object of the present invention is to provide an electrostatic adsorption apparatus which can stably and reliably hold a substrate in response to an increase in size of an insulating substrate.

Another object of the present invention is to maintain the substrate stably and reliably in response to the enlargement of the insulating substrate, and to uniformly control the temperature of each part of the substrate so as to perform in-plane uniform plasma processing on the substrate and the plasma processing. To provide a way.

Another object of the present invention is to provide a plasma processing apparatus and a plasma processing method capable of preventing abnormal discharges due to poor holding, end defects or misalignment of a substrate to be mounted.

In order to achieve the above object, the electrostatic adsorption apparatus of the present invention is a substrate holding apparatus for holding a substrate to be processed which is made of an insulator in a space where a plasma is formed, comprising: a susceptor made of a conductor for supporting the substrate; A first dielectric layer formed by thermal spraying on the main surface of the susceptor, an electrode layer formed by thermal spraying on the first dielectric layer, a second dielectric layer formed by thermal spraying on the electrode layer, and applying a DC (direct current) voltage to the electrode layer A DC voltage application unit, and by applying a DC (direct current) voltage to the electrode layer, charges are accumulated on the surface to be processed of the substrate mounted on the second dielectric layer, and the electrostatic attraction acts between the charge and the electrode layer. Adsorb and hold the substrate.

In the above configuration, the DC voltage from the DC voltage applying unit is applied to the electrode layer completely insulated from the surroundings by the first and second dielectric layers, and is not directly applied to the susceptor. As a result, abnormal discharge is unlikely to occur between the susceptor and the plasma, and abnormal discharge between the electrode layer to which the DC voltage is applied and the plasma can be prevented. In the first and second dielectric layers, it is desirable to ensure the reliability as an insulator against a high voltage DC voltage and to have a volume resistivity of 1 × 10 ¹⁴ Ω · cm or more, and the materials A1 ₂ O ₃ and ZrO. the ceramics which at least one as a main component is preferably of _2.

According to a suitable embodiment of the present invention, the through hole of the heat transfer gas for controlling the temperature of the substrate is installed through the susceptor from the upper surface of the second dielectric layer, the electrode layer is not exposed to the inner wall surface of the through hole Take it. According to this through-hole inner wall insulator structure, even if a leakage path of the heat transfer gas is possible between the substrate and the second dielectric layer, the electrode layer is not electrically coupled with the plasma, and no abnormal discharge occurs. The susceptor may be provided with a cooling mechanism or a heating mechanism for performing temperature control of the substrate by a cooling method or a heating method.

According to one embodiment of the invention, the high frequency from the high frequency power source is applied to the susceptor with the desired power. In this case, a configuration in which the DC voltage application unit has a DC power supply that outputs a DC voltage and a resistor or low-pass filter that substantially blocks the high frequency from the high frequency power supply and passes the DC voltage is also preferable. . By the high frequency blocking function of such a resistor or a low pass filter, the DC voltage application portion can be protected from the high frequency of the susceptor side.

In addition, according to one preferred embodiment, the susceptor is grounded to the ground via a resistor. When a DC voltage is applied from the DC voltage applying unit to the electrode layer, the potential of the susceptor rises to near the DC voltage by capacitive coupling through the first dielectric layer, but the potential of the susceptor drops to near the ground electric field through the resistor. Abnormal discharge between the acceptor and the plasma can be prevented.

Further, according to one preferred embodiment, a thermal stress buffer having an expansion coefficient between the expansion ratio of the first dielectric layer and the expansion ratio of the susceptor is inserted between the first dielectric layer and the susceptor. As described above, when the first dielectric layer is made of ceramics mainly composed of Al ₂ O ₃ or ZrO ₂ , and the susceptor is made of Al metal, a Ni-5Al alloy can be suitably used as such thermal stress buffer. have. By inserting such a thermal stress buffer member, the thermal stress resistance of the first dielectric layer is greatly improved, and cracking is less likely to occur.

A first plasma processing apparatus of the present invention is a plasma processing apparatus for performing a desired plasma processing on a substrate to be processed made of an insulator, comprising: a processing container for providing a processing space for the plasma processing; Electrostatic adsorption apparatus of the present invention for holding a substrate, a processing gas supply unit for supplying a processing gas into the processing chamber, an exhaust unit for exhausting the interior of the processing chamber, and a plasma generating plasma of the processing gas in the processing chamber It has a generation part.

In the first plasma processing apparatus, even if the insulated substrate is large, the electrostatic adsorption apparatus of the present invention stably and reliably holds the substrate, so that the temperature of each part of the substrate is uniformly controlled to provide uniform in-plane uniformity on the substrate. Plasma processing can be performed.

A second plasma processing apparatus of the present invention is a plasma processing apparatus for performing a desired plasma processing on a substrate to be processed made of an insulator, the processing vessel providing a processing space for the plasma processing, and the substrate in the processing container. An electrostatic adsorption apparatus of the present invention for maintaining the pressure, a process chamber in which a predetermined plasma process is performed on the substrate, a process gas supply unit for supplying a process gas into the process chamber, an exhaust unit for exhausting the interior of the process chamber, And a plasma generating unit for generating plasma of a processing gas in the processing chamber, and an electrothermal gas supply unit for supplying a heat transfer gas to the rear surface of the insulating substrate mounted on the second dielectric layer of the electrostatic adsorption apparatus.

In the second plasma processing apparatus, the electrostatic adsorption apparatus of the present invention is provided so as to penetrate from the susceptor of the through hole of the heat transfer gas to the upper surface of the second dielectric layer for controlling the temperature of the substrate, and the electrode layer is formed in the through hole. It has a structure that is not exposed to the wall surface, that is, a through hole inner wall insulating groove. As a result, no abnormal discharge from inside the through hole occurs.

In one suitable embodiment of the second plasma processing apparatus, a gas flow rate monitoring unit for monitoring a supply flow rate of the heat transfer gas supplied to the back surface of the substrate from the heat transfer gas supply unit, and the measured value of the gas supply flow rate is compared with a predetermined reference value. Thus, a sequence control unit for determining whether or not to activate the plasma generation unit is provided according to the comparison result. Preferably, the heat transfer gas is He gas, and the gas pressure supplied to the back surface of the substrate is set within the range of 1 Torr to 10 Torr, and the DC voltage applied to the electrode layer of the electrostatic adsorption device may be set within the range of 2 kV to 5 kV.

According to a suitable embodiment, the monitor link is supplied to the back surface of the substrate at a first pressure, and the heat transfer gas is applied to the back surface of the substrate at a second pressure greater than the first pressure when the plasma processing is performed on the substrate. Supply.                         

The plasma processing method of the present invention is a method of performing plasma processing using the second plasma processing apparatus, including mounting the substrate on a second dielectric layer of the electrostatic adsorption apparatus, and processing the processing chamber of the processing apparatus. After introducing the gas, applying a DC voltage to the electrode layer of the electrostatic adsorption device, and starting the application of the DC voltage, the electrothermal gas is supplied to the rear surface of the substrate at a predetermined pressure from the electrothermal gas supply unit. And monitoring the supply flow rate and comparing the measured value of the heat transfer gas flow rate with a predetermined reference value, and determining whether to generate plasma of the processing gas in the processing chamber according to the comparison result.

According to the plasma processing method of the present invention, the processing gas is introduced into the processing vessel, and at the same time as before and after, a DC voltage is applied to the electrode layer of the electrostatic adsorption apparatus, and then the electrothermal gas pressure is applied to the insulating substrate. Part of the ionization of the processing gas causes the glass substrate upper surface to be appropriately charged to obtain an appropriate electrostatic attraction force, and the electrothermal gas leakage flow rate is monitored under this electrostatic attraction force. As a preferred embodiment, when the measured value of the heat transfer gas flow rate is less than or equal to the reference value, the plasma of the process gas may be generated in the processing chamber to perform plasma processing on the substrate, and when the measured value of the heat transfer gas flow rate exceeds the reference value, The plasma processing on the substrate may be stopped without generating plasma of the processing gas in the processing chamber. Thereby, abnormal discharge resulting from holding failure of a board | substrate, defect of an edge part, or mounting misalignment etc. can be prevented in a mounting object.

Hereinafter, preferred embodiments of the present invention will be described with reference to FIGS. 1 to 12.

Example 1

1 shows a configuration of an electrostatic adsorption apparatus according to the first embodiment of the present invention. This electrostatic adsorption device fixes and holds an insulating substrate for FPD, for example, a glass substrate G, in a processing vessel of a plasma processing apparatus, and has a rectangular mounting table 10 corresponding to the rectangular glass substrate G. . In the mounting table 10, a rectangular block-shaped susceptor 14 made of a conductor such as aluminum on the base member 12, and an insulator such as ceramic or quartz surrounding the susceptor 14 are formed. Three layers of the lower dielectric layer 18, the electrode layer 20, and the upper dielectric layer 22 provided with a rectangular frame-shaped focus ring 16 and formed on the main surface (upper surface) of the susceptor 14 by thermal spraying, respectively. The electrostatic adsorption part 24 which consists of a structure is provided.

Here, the lower dielectric layer 18 and the upper dielectric layer 22 may be formed of an insulator having a volume resistivity of 1 × 10 ¹⁴ Ωcm or more, preferably at least one of alumina (Al ₂ O ₃ ) and zirconia (ZrO ₂ ). It is made of ceramics. The electrode layer 20 may be any conductor material, for example made of tungsten. By the known plasma spraying method, three layers of the lower dielectric layer 18, the electrode layer 20, and the upper dielectric layer 22 can be sequentially formed on the main surface of the susceptor 14.

The coolant flow path 26 is provided inside the susceptor 14, and the temperature-controlled coolant from the cooling device (not shown) flows through the coolant flow path 26. As shown in FIG. In addition, the upper surface of the susceptor 14 and the electrostatic adsorption portion ((24) (18, 20, 22)) are provided with a plurality of through holes 28, and He from the He gas supply system (not shown). The gas passes through the gas flow path inside the susceptor and the through hole 28 as the heat transfer gas, and is supplied to the rear surface of the glass substrate G at a predetermined pressure.

As shown in FIG. 2, a circular cutout (notch) 20a having a larger diameter than the through hole 28 is formed in the electrode layer 20 (shown in diagonal lines) around the through hole 28. The electrode layer 20 is not exposed even in the through hole 28, and the middle or upper wall surface in the through hole 28 is constituted by the lower dielectric layer 18 and the upper dielectric layer 22. As shown in FIG. In addition, the outer circumferential end of the electrode layer 20 is also drawn inside the outer circumferential ends of the lower dielectric layer 18 and the upper dielectric layer 22, and has a structure not exposed to the outside. In this manner, all of the electrode layers 20 are buried between the lower dielectric layer 18 and the upper dielectric layer 22.

In FIG. 1, the output terminal of the high frequency power supply 32 is electrically connected to the susceptor 14 via a matching device 30. The output frequency of this high frequency power supply 32 is selected in the range of several MHz to several tens of MHz, and the output power is selected in the order of several kW. On the other hand, the output terminal of the direct current (DC) power supply 34 is electrically connected to the electrode layer 20 of the electrostatic adsorption part 24 via the high frequency interruption | blocking part 36. As shown in FIG. The high frequency cut-off part 36 is for blocking the high frequency from the susceptor 14 side, and it is preferable that the high frequency cut-off part 36 is constituted by a resistor having a high resistance value of 1 MΩ or more or a low-pass filter through which a direct current is passed. The switch 38 is for switching the DC power supply 34 and the ground potential with respect to the electrode layer 20.

The plasma PZ of the processing gas is generated on the glass substrate G during the plasma processing. The plasma PZ may be generated by a high frequency from the high frequency power supply 32, or may be generated by a high frequency from another high frequency power source (not shown). In the latter case, the high frequency applied from the high frequency power supply 32 to the susceptor 14 is used for the bias for introducing ions in the plasma PZ into the upper surface (the surface to be processed) of the glass substrate G.

When the switch 38 is switched to the DC power supply 34 side, the DC voltage from the DC power supply 34 is applied to the electrode layer 20. When this DC voltage is an electrode voltage, negative charges (electrons and anions) are attracted and accumulated on the upper surface of the glass substrate G. As a result, the negative electric charges on the upper surface of the glass substrate G and the electrostatic force, ie, the coulomb force, which are attracted to each other by inserting the glass substrate G and the upper dielectric layer 22 between the electrode layer 20, are applied. The glass substrate G is attracted and fixed on the mounting table 10 by the attraction force. When the switch 38 is switched to the ground side, the electrode layer 20 is discharged, and thus, the glass substrate G is also discharged to release the coulomb force, that is, the electrostatic attraction force.

In this electrostatic adsorption device, the DC voltage from the DC power supply 34 is applied to the electrode layer 20 completely isolated from the surroundings by the lower dielectric layer 18 and the upper dielectric layer 22, and directly to the susceptor 14. Not authorized As a result, abnormal discharge hardly occurs between the susceptor 14 and the plasma PZ, and abnormal discharge does not occur even between the electrode layer 20 to which the DC voltage is applied and the plasma PZ. In particular, since the inner wall of the through hole 28 is also composed of the dielectric layers 18 and 22, abnormal discharge does not occur even if a leak path of He gas is generated on the contact surface of the substrate G and the upper dielectric layer 22. Therefore, the DC voltage can be made high to increase the electrostatic attraction. For this reason, it is possible to increase the He gas supply amount, and even if the size of the glass substrate G is large, good and uniform substrate temperature control can be performed.

In addition, in this electrostatic adsorption device, the high frequency breaker 36 connected between the susceptor 14 and the DC power supply 34 prevents the high frequency of the susceptor 14 from leaking to the DC power supply 34. By blocking, the DC power supply 34 can be protected from high frequency.

Example 2

3 shows the configuration of the electrostatic adsorption apparatus according to the second embodiment of the present invention. In the figure, the same code | symbol is attached | subjected to the part which has the same structure or function as the thing of said 1st Example (FIG. 1). In this second embodiment, a thermal stress buffer 40 having a film shape (for example, a film thickness of 50 µm) is provided between the susceptor 14 and the lower dielectric layer 18. This thermal stress buffer 40 can also be formed by a plasma spraying method.

For example, in plasma etching, although depending on the plasma processing conditions, the susceptor temperature may be set at around 80 ° C. In this case, thermal abrasion occurs in the dielectric layers 18 and 22 due to the difference in the expansion ratio between the dielectric layers 18 and 22 and the susceptor 14 among the electrostatic adsorption portions 24, which may cause dielectric breakdown. . In particular, when a high voltage is applied to the electrode layer 20, there is a fear that even slight fatigue due to thermal stress of the dielectric layers 18 and 22 may reach insulation breakdown.

MEANS TO SOLVE THE PROBLEM This inventor examined the insulator material which comprises the dielectric layers 18, 22, and the conductor material which comprises the susceptor 14 about the breakdown which arises from the thermal stress of the dielectric layers 18 and 22. As shown in FIG. As a result, it was found that the difference in expansion rate of the material between room temperature and 100 ° C is the most important, but the toughness (particularly the shear stress resistance) of the dielectric layer or the insulator material is also very important. In addition, the susceptor 14 preferably has high heat conductivity, low metal contamination, and high workability. The materials of the dielectric layers 18 and 22 have high insulation, high dielectric constant, and high susceptor top surface. It was confirmed that it is preferable to have adhesiveness.

As shown in FIG. 3, it has been found that interposing the thermal stress buffer 40, which is a conductor material, in the interface region between the susceptor 14 and the lower dielectric layer 18 is most effective in all respects. In this embodiment, the susceptor 14 is made of A1 metal, and the materials of the lower dielectric layer 18 and the upper dielectric layer 22 are made of alumina (Al ₂ O ₃ ) having high withstand voltage or high zirconia (ZrO). ₂ ), and the thermal stress buffer 40 is made of a Ni-5Al alloy. Here, the Ni-5Al alloy is an alloy having a (atomic) hybrid ratio of nickel and aluminum of 1: 5, and the linear expansion coefficient is larger than that of alumina or zirconia, as shown in Table 1, and the linear expansion coefficient of the aluminum metal. Smaller than As described above, as the material of the thermal stress buffer 40, the coefficient of linear expansion (expansion coefficient) is preferably an intermediate value between the dielectric layers 18 and 22 and the susceptor 14, and the adhesion between the dielectric layers 18 and 22 is high. Do.

Table 1

material Al metal Ni-5Al Alloy Alumina Zirconia Linear Expansion Coefficient × 10 ^-6 / ℃ 23.1 12.0 6.4 10.5

As such, by providing the thermal stress buffer 40 having the intermediate expansion coefficient between the susceptor 14 and the lower dielectric layer 18, the thermal stress resistance of the electrostatic adsorption portion 24 is greatly improved, and the thermal stress is increased. Insulation breakdown of the dielectric layers 18 and 22 due to this can be reduced. Thereby, application of DC of the high voltage to the electrode layer 20 is attained with high reliability, and the glass substrate G can be stably fixed on the mounting table 10 stably under high reliability.

Example 3

4 shows the configuration of the electrostatic adsorption apparatus according to the third embodiment of the present invention. In the figure, the same code | symbol is attached | subjected to the part which has the same structure or function as the thing of said 1st and 2nd Example (FIG. 1, FIG. 3).

In the electrostatic adsorption apparatus of the present invention, the electrode layer 20 and the susceptor 14 are capacitively coupled via the lower dielectric layer 18. For this reason, as shown in FIG. 5, when DC voltage of phi _p (for example, 5 kV) is applied to the electrode layer 20 from the DC power supply 34, the potential of the susceptor 14 also becomes Φ _p by capacitive coupling. Rises to Φ _so close to (eg around 4 kV). If the plasma is ignited in this state (or DC application is started during plasma generation), there is a fear that arc discharge occurs between the susceptor 14 and the plasma PZ in the high potential state.

Therefore, in this third embodiment, the susceptor 14 is grounded to the ground via the resistor 42. Even if the potential of the susceptor 14 rises to several kV immediately after the start of the DC voltage application by the capacitive coupling as described above, the potential of the susceptor 14 is changed to? _S1 in FIG. 5 via the resistor 42. Likewise, it can be exponentially lowered to ground potential. Thereby, arc discharge between the susceptor 14 and the plasma PZ can be prevented. On the other hand, the resistor 42 needs to have a high resistance value R ₄₂ that can substantially block the high frequency applied from the high frequency power supply 32 to the susceptor 14. In this resistor ₄₂ , the appropriate range of the resistance value R ₄₂ for making the high frequency interruption function and the DC potential clamp function as described above compatible is 1 MΩ to 10 MΩ.

Example 4

Next, an embodiment of the plasma processing apparatus provided with the electrostatic adsorption apparatus of the present invention will be described. 6 shows the configuration of an inductively coupled plasma (ICP) etching apparatus according to one embodiment. This plasma etching apparatus enables low-pressure, high-density plasma generation, and for etching metal films, ITO films, oxide films, etc. at high speed when forming thin film transistors (TFTs) on glass substrates, for example, in LCD manufacturing. Is used. In the figure, the same code | symbol is attached | subjected to the part which has the same structure or function as the thing of said 1st-3rd Example (FIGS. 1-4).

This plasma etching apparatus has a main body container 50 hermetically sealed in a columnar shape made of a conductive material such as aluminum having anodized (anodic oxidation). The main body container 50 is grounded to the ground. The interior of the main body container 50 is divided into an upper antenna chamber 54 and a lower processing chamber 56 by a dielectric wall 52 extending horizontally. The dielectric wall 52 is made of ceramic or quartz such as Al ₂ O ₃ , and forms a ceiling wall on the processing chamber 56 side. Between the side wall 54a of the antenna chamber 54 and the side wall 56a of the processing chamber 56, a support shelf 58 protruding inward is provided, and on the support shelf 58, a dielectric wall 52 is disposed. It is provided through this sealing member (not shown), and it is fixed by the bis (not shown).

The dielectric wall 52 has an assembly structure, and a substantially front surface of the lower surface thereof is covered with a cover member 60 made of a dielectric such as ceramics and quartz, and a shower head 62 for processing gas supply is provided therein. It is. The shower head 62 is made of aluminum, for example, anodized on its inner surface. In the shower head 62, a gas flow path or a buffer chamber 64 is formed to extend horizontally. A plurality of gas discharge holes 64a extending downward and opening through the cover member 60 communicate with the buffer chamber 64. On the other hand, a gas supply pipe 66 communicating with the buffer chamber 64 is attached to the center of the upper surface of the dielectric wall 52. The gas supply pipe 66 penetrates outward from the ceiling of the body container 50 and is connected to a processing gas supply system 68 including a processing gas supply source, a valve system, and the like. During the plasma etching, the processing gas from the processing gas supply system 68 is introduced into the shower head 64 via the gas supply pipe 66, and is discharged into the processing chamber 56 from the gas supply holes 64a on the lower surface thereof. have.

In the antenna chamber 54, the high frequency antenna 70 which consists of a planar coil antenna wound by the substantially spiral shape on the dielectric wall 52 is arrange | positioned. The spiral center end of the high frequency antenna 70 is led to the outside from the ceiling of the main body container 50 and is electrically connected to the output terminal of the high frequency power source 74 via the matching unit 72. On the other hand, the outer end of the vortex is electrically connected to the main body container 52 and grounded to the ground via the main body container 52.

During plasma etching, a high frequency power of a predetermined frequency, for example, 13.56 MHz, is supplied from the high frequency power supply 74 to the high frequency antenna 70 via the matching unit 72, so that an alternating electric field parallel to the high frequency antenna 30 is generated in the processing chamber ( The process gas formed in 56 and supplied to the process chamber 56 from the shower head 64 by this alternating electric field becomes plasma. The output power of the high frequency power supply 74 may be appropriately set so as to be a value sufficient to generate plasma.

Below the process chamber 56, the mounting table 10 of the electrostatic adsorption apparatus according to the present invention is provided so as to face the high frequency antenna 70 by inserting the dielectric wall 52. In this plasma etching apparatus, the mounting table 10 is housed in a tray 76 made of an insulator and supported by a hollow post 78. The strut 78 penetrates the bottom part of the main body container 50 while maintaining an airtight state, and is supported by a lifting mechanism (not shown) disposed in addition to the main body container 50. At the time of carrying in and out of the board | substrate G, the mounting base 10 is moved to an up-down direction by the drive of the said lifting mechanism. Between the tray 76 and the bottom plate part of the main body container 50, the bellows 80 which surrounds the support | pillar 78 airtightly is provided, and also the airtightness in the process chamber 56 also moves up and down the mounting table 10. This is to be maintained. Moreover, the gate valve 82 for opening and closing a board | substrate carrying-in exit is provided in the side wall 56a of the process chamber 56. As shown in FIG.

The base member 12 of the mounting table 10 is made of a conductor material such as aluminum or stainless steel, and the high frequency power supply 32 is electrically connected to the base member 12 via the matching unit 30 and the feed rod. have. During plasma etching, a high frequency of 32 MHz bias is applied to the susceptor 14 via the base member 12 during the plasma etching, and ions in the plasma generated in the processing chamber 56 are effectively mounted ( It enters into the glass substrate G on 10). Here, the high frequency power supplied from the high frequency power supply 32 is usually set to a value lower than the high frequency power for plasma generation supplied from the upper high frequency power supply 74.

All piping and wiring to each part of the mounting table 10 are drawn out of the main body container 50 through the hollow support | pillar 78, and are connected to various power sources or various power / control devices. The He gas sent out from the He gas supply system 84 is pressure-controlled by a PCV (Pressure Control Valve) 86 and then transferred to the through hole 28 of the mounting table 10. The flow rate measuring device 88 attached to the PCV 86 detects the flow rate of the He gas supplied to the through hole 28 side, and is used to monitor the leak flow rate of the He gas at the time of electrostatic adsorption described later. . The gas flow rate measurement value obtained by the flowmeter 88 is given to the control part 90.

An exhaust port 94 including an exhaust pipe 92 and a vacuum pump (not shown) is connected to the exhaust port provided at the bottom of the processing chamber 56. The exhaust mechanism 94 exhausts the interior of the processing chamber 56 and maintains the interior of the processing chamber 56 in a predetermined vacuum atmosphere (for example, 10 mTorr = about 133 kPa) during the plasma processing. The control part 90 may be comprised by a microcomputer, and each part of this plasma etching apparatus, ie, the high frequency power supply 32, 74, the switch 38, the processing gas supply system 68, and the He gas supply system 84 The exhaust mechanism 94 and the like are individually controlled, and the operation sequence of the entire apparatus is controlled.

In this plasma etching apparatus, glass substrate G may be large, and since the electrostatic adsorption apparatus of this invention keeps the said board | substrate G stably and reliably, the temperature of each board | substrate is uniformly controlled and a board | substrate is used. In-plane uniform plasma etching can be performed on the surface.

Next, the preferable aspect of the electrostatic adsorption apparatus built in this plasma etching apparatus is demonstrated.

In FIG. 7, the experiment result which investigated the board | substrate cooling effect of the He gas for heat transfer with respect to the glass substrate G on the mounting table 10 is shown. In this experiment, the supply pressure of He gas was changed, and the temperature of the measurement point set in the other position on the board | substrate was measured using the thermocouple. As a representative measurement point, "center" is the substrate center and "edge" is the substrate end. Main conditions are as follows.

Board size (diagonal dimension) = 500 mm

Board thickness of board = 0.7mm

Pressure in chamber = 30mTorr

Process gas = O ₂

High Frequency Power (13.56MHz / 3.2MHz) = 5000W / 3000W

DC voltage = 2500V

Time = 180 seconds

During plasma etching, the temperature of the glass substrate G rises due to heat input from the plasma, but the substrate temperature is lowered to a certain value by bringing the He gas into contact with the back surface of the substrate from the susceptor 14 side, and the temperature in the substrate surface is uniform. I can keep it. As can be seen from FIG. 7, when the He gas pressure is 0 Torr to 2 Torr, the cooling effect is increased with increasing pressure, and the substrate temperature is lowered. However, when the He gas pressure is 2 Torr or more (particularly 3 Torr or more), saturation is observed in the cooling effect. Thereby, it is preferable to make the He gas pressure for heat transfer used for this plasma etching apparatus into 2 Torr or more. On the other hand, since the He gas pressure acts on the back surface of the insulated substrate and acts in a direction that separates the insulated substrate from the mounting table or causes mounting misalignment, the He gas pressure more than necessary is undesirable. As a result, the He gas pressure is preferably about 10 Torr.

8 shows the relationship between the DC voltage applied to the electrode layer 20 and the adsorption pressure (electrostatic adsorption force) with respect to the glass substrate G. As shown in FIG. As shown, the adsorption pressure increases in proportion to the square of the DC applied voltage. As explained in Fig. 7, it is considered that from the viewpoint of the substrate cooling effect, the He gas pressure is about 5 Torr. This means that the adsorption pressure for fixing and holding the substrate against the He gas pressure is sufficient to 5 Torr. In Fig. 9, the relationship between the insulating film thickness and the applied voltage required to obtain the adsorption pressure of 5 Torr is shown by the characteristic curve (straight line) A, and the dielectric breakdown voltage of the insulating film itself is shown by the characteristic curve (straight line) B. do. The region of the diagonal portion (the region enclosed by A and B) in the figure is a combination of the insulating film thickness and the applied voltage. Thus, it can be said that the thickness of the insulating film is 400 mu m and the applied voltage is preferably about 5 kV.

Although the alumina film was demonstrated as a material of the dielectric layers 18 and 22 in FIG. 9, the zirconia film formed by the thermal spraying method was also examined and confirmed that it can be used sufficiently. As described above, since zirconia is high in toughness and particularly strong in thermal stress, it is also suitable for increasing the reliability of the electrostatic adsorption unit. In addition, zirconia is excellent in plasma resistance like alumina, and its relative dielectric constant is 20 to 30, which is more than twice that of the alumina film 10. Usually, since the adsorption force (adsorption pressure) increases in proportion to the square of the dielectric constant of the dielectric layer, it can be said to be more promising ceramics than alumina in the future. Among them, the zirconia has a higher leakage current (hopping current) in the film than the alumina film, and the thickness of the zirconia must be increased in order to suppress the leakage current and secure the reliability of FIG. 9. Also, the adsorption pressure decreases in inverse proportion to the square of the film thickness. In short, the alumina film is excellent in terms of voltage resistance and thinning, and the zirconia film is excellent in toughness or crack resistance, and both can be suitably used as materials for the dielectric layers 18 and 22. In the ceramic material constituting the dielectric layers 18 and 22, when the alumina (A1 ₂ O ₃ ) and the zirconia (ZrO ₂ ) are mixed, the component ratio is preferably about 50%: 50%.

As described above, the dielectric layer formed by the thermal spraying method as in the present invention is superior in insulation property to the insulator layer of the ordinary ceramic sintered body. In addition, the thermal spraying method has an advantage of easily forming a dielectric film even on a large surface of a member, and can be effectively applied to a mounting table facing a large substrate.

Next, with reference to FIG. 10 and FIG. 11, the characteristic operation | movement in the plasma etching apparatus of this Example is demonstrated.

10, the equivalent circuit of the principal part around the mounting table 10 in this plasma etching apparatus is shown. In this equivalent circuit, SW ₁ is the changeover switch 38, SW ₂ is the on / off switch of the high frequency power supply 32, R ₃₆ and R ₄₂ are the high frequency breaker 36, the resistance of the resistor 42, C ₁₈ is the capacitance of the lower dielectric layer 18, C _{G, 22} is the series capacitance of the glass substrate G and the upper dielectric layer 22, Z _p is the impedance of the plasma. The nodes N ₂₀ and N ₁₄ correspond to the electrode layer 20 and the susceptor 14. 11 shows an operation sequence immediately after the start of this plasma etching process. This operation sequence is executed under the control of the control unit 90.

First, the process gas supply system 68 is operated, and the process gas is introduced into the process chamber 56 by passing through the shower head 94. Before and after this, the switch SW ₁ 38 is switched to the DC power supply 34. As a result, the DC voltage from the DC power supply 34 is applied to the node N ₂₀ (electrode layer ₂₀ ) via the resistor R ₃₆ . The potential of this node 20 rises to approximately time constant C ₁₈ × (R ₃₆ + R ₄₂ ) as Φ _p in Fig. 5. The charge is accumulated on the upper surface of the glass substrate G by applying the DC voltage. The glass substrate G is mounted on the mounting table 10 (more accurately, the upper dielectric layer 22) by the electrostatic attraction (coulomb force) acting between the surface charge and the electrode layer 20 on the mounting table 10 side. On the other hand, if the potential of the node 20 rises as described above, the potential of the node N ₁₄ (the susceptor ₁₄ ) is caused by the coupling through the capacitor C ₁₈ . However, since the node N ₁₄ is grounded to the ground via the resistor R ₄₂ , the potential of the node N ₁₄ is approximately time constant [C ₁₈ × (R ₃₆ + R _42). )] And exponentially as quickly as Φ _s1 in FIG. 5 to the ground potential.

As described above, the switch (SW ₁ ) 38 is switched to the DC power supply 34 to operate the He gas supply system 84 after a predetermined time so that the He gas is applied to the substrate G on the mounting table 10. Supply. In addition, a cooling medium is supplied to the refrigerant passage 26 of the susceptor 14 before starting the plasma treatment. In starting the supply of the He gas, a supply pressure (for example, 1.5 Torr) lower than a set value (for example, 4 Torr) at the time of processing is selected. Then, the He gas flow rate at that time is monitored by the flow rate measuring instrument 88 and the control unit 90. When the monitor value (He flowmeter measured value) is below the reference value, it is determined that the amount of leakage of He gas in the mounting table 10 is within the allowable range, and the switch SW ₂ is turned on to turn on the high frequency. Power is turned on and the plasma is ignited (SW ₃ on). Then, the He gas flow rate is increased to the original set value (normal value), and predetermined plasma etching is performed. However, as indicated by the dotted line in Fig. 11, when the monitor value (He gas flow rate measured value) exceeds the reference value, it is determined that the amount of leakage of He gas in the mounting table 10 exceeds the allowable range, and the switch is The processing is stopped or stopped without turning on (SW ₂ , SW ₃ ) and eventually generating no plasma.

Thus, as a cause of considerable gas leakage from the beginning of supply of He gas, sufficient electrostatic adsorption force as set to the glass substrate G on the mounting table 10 does not act, or the glass substrate G The case where the edge part of) is broken, the mounting position of the glass substrate G, etc. are shift | deviated, etc. are considered. In any case, if plasma is generated with such a trouble, abnormal discharge may occur at that time, resulting in electrode breakage. In this embodiment, since such trouble can be detected early by monitoring the He gas leakage flow rate before the generation of plasma, abnormal discharge can be prevented in advance.

In the operation sequence of this embodiment, the order of first introducing the processing gas into the processing chamber 56 and then adding the He gas pressure to the glass substrate G is important. In other words, a portion of the glass substrate G is properly charged by the introduction of the processing gas, so that an appropriate electrostatic attraction force is obtained. On the other hand, in the procedure of adding the He gas pressure in a state of high vacuum in the processing chamber 56 without introducing the processing gas, the electrostatic adsorption force applied to the glass substrate G is very weak, and even at a low He gas pressure, the glass There is a possibility that the substrate G is detached from the mounting table 10 or a position shift occurs. Moreover, the electrostatic adsorption force at the time of process gas introduction may change with the kind of process gas, or a difference in flow volume. When sufficient electrostatic attraction force (for example, 2 Torr or more) can be obtained only by introducing the processing gas, the He gas may be supplied at the original set flow rate from the beginning.

In addition, with respect to the order of the timing of introducing the processing gas and the timing of turning on the switch SW ₁ , the same effects as described above can be obtained by turning on the SW ₁ first and introducing the processing gas later.

Example 5

12 shows the configuration of a capacitively coupled plasma (CCP) etching apparatus as another example of the plasma processing apparatus provided with the electrostatic adsorption apparatus of the present invention. In the figure, the same code | symbol is attached | subjected to the part which has the same structure or function as the thing (FIG. 6) of the plasma etching apparatus in the said 4th Example.

This plasma etching apparatus has the chamber (processing container) 100 shape | molded in the prismatic shape which the surface is made of the anodized aluminum, for example. At the bottom of the chamber 100, a mounting table 10 of the electrostatic adsorption apparatus according to the present invention is provided. Here, the base member 12 of the mounting table 10 is made of an insulator material, and the susceptor 14 constituting the lower electrode is insulated from and separated from the chamber 100.

Above the mounting table 10, a shower head 102 serving as an upper electrode is provided so as to face the susceptor 14 in parallel. The shower head 102 is supported at the upper portion of the chamber 100 and has a buffer chamber 104 therein, and a plurality of discharge holes 106 for discharging the processing gas on the lower surface facing the susceptor 14. Is formed. The shower head 102 is grounded to the ground and constitutes a pair of parallel flat electrodes together with the susceptor 14.

The gas inlet 108 is provided on the upper surface of the shower head 102, and the process gas from the process gas supply system 68 is transferred to the buffer chamber 104 of the shower head 102 through the gas inlet 108. Is introduced. As the processing gas (etching gas), gases generally used in this field, such as halogen-based gas, O ₂ gas, and Ar gas, can be used. The high frequency applied from the high frequency power supply 32 to the susceptor 14 is selected to be a relatively high high frequency, for example, 13.56 MHz, and serves both for plasma generation and bias. Also in this CCP etching apparatus, the effect of this invention is acquired similarly to the said ICP etching apparatus.

Although the plasma processing apparatus of the above embodiment is related to the etching apparatus, the same applies to the application examples of plasma CVD of an insulator film, a conductor film or a conductor film, plasma cleaning of an insulating substrate surface, plasma cleaning of an inner wall of a chamber, and the like. . In this case, the present invention is equally applicable to the method of grounding the susceptor side of the electrostatic adsorption device. In addition, the present invention can be applied to a plasma processing apparatus using helicon wave plasma generation, ECR (Electron Cyclotron Resonance) plasma generation, etc. as plasma generation. Although the monitoring function of the electrothermal gas leakage flow rate in this invention, and the abnormality detection function or operation sequence function based on this monitoring mechanism can be suitably applied to the plasma processing apparatus provided with the electrostatic adsorption apparatus of this invention as mentioned above, It is applicable to the plasma processing apparatus provided with the arbitrary electrostatic adsorption apparatus which uses a gas.

In addition, various modifications are possible within the scope of the technical idea of the present invention. For example, the method of applying a negative DC voltage to the electrode layer 22 in the electrostatic adsorption apparatus of this invention, the structure which provides the heating mechanism in the susceptor 14, etc. are also possible. It is also possible to use different insulator materials for the lower dielectric layer 18 and the upper dielectric layer 22. The to-be-processed board | substrate of the insulator in this invention is not limited to an LCD glass substrate, It is applicable also to the arbitrary insulated substrates for FPD, and the insulated substrate of other uses.

According to the electrostatic adsorption apparatus of the present invention, by the above-described configuration and action, the holding force on the insulating substrate is increased without causing abnormal discharge or dielectric breakdown, so as to stably and reliably maintain even a large substrate, thereby improving reliability. You can.

According to the plasma processing apparatus and the plasma processing method of the present invention, by the above-described configuration and operation, the substrate is stably and reliably maintained in response to the enlargement of the insulating substrate, and the entire substrate is uniformly cooled to face the substrate. Uniform plasma processing can be performed. In addition, abnormal discharges due to poor holding, end defects or misalignment of the substrate to be mounted can be prevented.

Claims (21)

An electrostatic adsorption device for electrostatically adsorbing and holding a substrate to be processed made of an insulator in a space where plasma is generated, A susceptor made of a conductor for supporting the substrate; A first dielectric layer formed on the main surface of the susceptor by thermal spraying, An electrode layer formed on the first dielectric layer by a thermal spraying method, A second dielectric layer formed on the electrode layer by a thermal spraying method, A DC voltage application unit for applying a DC voltage to the electrode layer, and applying the DC voltage to the electrode layer to accumulate charge on the surface to be processed of the substrate mounted on the second dielectric layer, and operate between the charge and the electrode layer. To adsorb and maintain the substrate by electrostatic attraction, The through hole of the heat transfer gas for controlling the temperature of the substrate penetrates from the susceptor to the upper surface of the second dielectric layer, the electrode layer is not exposed to the inner wall surface of the through hole, A high frequency power source that outputs a high frequency with a desired power to the susceptor is electrically connected, The DC voltage applying unit includes a current power supply for outputting the DC voltage, and a resistor or a low pass filter that substantially blocks the high frequency from the high frequency power supply and passes the DC voltage. Electrostatic adsorption device. The method of claim 1, The volume resistivity of the first and second dielectric layers is 1 × 10 ¹⁴ Ωcm or more Electrostatic adsorption device. delete delete delete delete The method of claim 1, The susceptor is grounded to the ground via a resistor Electrostatic adsorption device. The method of claim 7, wherein The resistor has a resistance value of 1MΩ to 10MΩ Electrostatic adsorption device. The method of claim 1, Between the first dielectric layer and the susceptor, a thermal stress buffer having an intermediate expansion rate between the expansion rate of the first dielectric layer and the expansion rate of the susceptor is inserted. Electrostatic adsorption device. The method of claim 1, The first and second dielectric layers are made of ceramics containing at least one of Al ₂ O ₃ and ZrO ₂ as a main component. Electrostatic adsorption device. The method of claim 9, The susceptor is made of Al metal, and the thermal stress buffer is made of Ni-5Al alloy. Electrostatic adsorption device. The method of claim 1, The susceptor is provided with a cooling mechanism for cooling the substrate Electrostatic adsorption device. The method of claim 1, The susceptor is provided with a heating mechanism for heating the substrate Electrostatic adsorption device. In the plasma processing apparatus for performing a desired plasma processing to a to-be-processed substrate which consists of an insulator, A processing container for providing a processing space for the plasma processing; The electrostatic adsorption device according to claim 1 for holding the substrate in the processing container; A processing gas supply unit for supplying a processing gas into the processing container; An exhaust unit for exhausting the interior of the processing container; A plasma generation unit for generating a plasma of a processing gas in the processing container Plasma processing apparatus. In the plasma processing apparatus for performing a desired plasma processing to a to-be-processed substrate which consists of an insulator, A processing container for providing a processing space for the plasma processing; An electrostatic adsorption apparatus for holding the substrate in the processing container, comprising: a susceptor made of a conductor for supporting the substrate, a first dielectric layer formed by thermal spraying on a main surface of the susceptor, and a thermal spraying method on the first dielectric layer. And a substrate mounted on the second dielectric layer by applying the DC voltage to the electrode layer, the electrode layer having an electrode layer, a second dielectric layer formed by a thermal spraying method on the electrode layer, and a DC voltage applying unit for applying a DC voltage to the electrode layer. The through hole of the heat transfer gas for accumulating charge on the surface to be treated, adsorbing and holding the substrate by an electrostatic attraction acting between the charge and the electrode layer, and controlling the temperature of the substrate is provided from the susceptor. 2 provided through the upper surface of the dielectric layer, the electrode layer is exposed to the inner wall surface of the through hole The electrostatic adsorption device, A processing chamber in which predetermined plasma processing is performed on the substrate; A processing gas supply unit for supplying a processing gas into the processing chamber; An exhaust unit for exhausting the interior of the processing chamber; A plasma generation unit for generating a plasma of a processing gas in the processing chamber; It has an electrothermal gas supply part which supplies an electrothermal gas to the back surface of the said insulated substrate mounted on the 2nd dielectric layer of the said electrostatic adsorption apparatus. Plasma processing apparatus. The method of claim 15, A gas flow rate monitor unit configured to monitor a supply flow rate of the heat transfer gas supplied from the heat transfer gas supply unit to the rear surface of the substrate; And a sequence control unit for comparing the measured value of the supply flow rate with a predetermined reference value and determining whether to operate the plasma generation unit according to the comparison result. Plasma processing apparatus. The method of claim 15, The heat transfer gas is He gas, the gas pressure supplied to the back surface of the substrate is set in the range of 1 Torr to 10 Torr, the DC voltage applied to the electrode layer of the electrostatic adsorption apparatus is set in the range of 2 kV to 5 kV. Plasma processing apparatus. In the method of performing a plasma process using the plasma processing apparatus of claim 16, Mounting the substrate on a second dielectric layer of the electrostatic adsorption device; Introducing a processing gas into the processing chamber of the processing apparatus; Applying a DC voltage to an electrode layer of the electrostatic adsorption device; After starting the application of the DC voltage, supplying the heat transfer gas to the back surface of the substrate at a predetermined pressure from the heat transfer gas supply unit and monitoring the supply flow rate; Comparing the measured value of the heat transfer gas flow rate with a predetermined reference value, and determining whether to generate plasma of the processing gas in the processing chamber according to the comparison result; Plasma treatment method. The method of claim 18, When the measured value of the heat transfer gas flow rate is equal to or less than the reference value, plasma of the process gas is generated in the processing chamber to perform plasma processing on the substrate, and when the measured value of the heat transfer gas flow rate exceeds the reference value, Stopping plasma processing on the substrate without generating plasma of the processing gas in the processing chamber; Plasma treatment method. The method of claim 19, In the monitoring, the heat transfer gas is supplied to the back surface of the insulated substrate at a first pressure, and the heat transfer gas is supplied to the back surface of the insulated substrate at a second pressure greater than the first pressure when the plasma processing is performed on the substrate. doing Plasma treatment method. In the plasma processing apparatus for performing a desired plasma processing to a to-be-processed substrate which consists of an insulator, A processing container for providing a processing space for the plasma processing; A mounting table for mounting the substrate in the processing container; An electrostatic adsorption unit for fixing and maintaining the substrate with an electrostatic adsorption force on the mounting object; A temperature control mechanism for cooling or heating the substrate to be mounted from a substrate back side; A processing gas supply unit for supplying a processing gas to the processing container; A plasma generation unit for generating a plasma of a processing gas in the processing container; An electrothermal gas supply unit for supplying an electrothermal gas to the back surface of the insulating substrate mounted on the second dielectric layer of the electrostatic adsorption device; A gas flow rate monitor unit configured to monitor a supply flow rate of the heat transfer gas supplied from the heat transfer gas supply unit to the rear surface of the substrate; And a sequence control unit for comparing the measured value of the gas supply flow rate with a predetermined reference value and determining whether to operate the plasma generating unit according to a comparison result. Plasma processing apparatus.

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