JP2006278219A - Icp circuit, plasma treatment device, and plasma processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ICP circuit in which circuit adjustment is easy and in which plasma of high density is stably generated. <P>SOLUTION: The ICP circuit carries out a circuit action in a resonance condition or within allowable action range of the resonance condition, and is provided with a high frequency coil to which a high frequency current is supplied, an ICP power supply 18 which is connected to one end of the high frequency coil and from which the high frequency electric current is outputted, and with a resonance capacitor 20 which is connected to the other end of the high frequency coil and which has a capacity to satisfy the resonance condition or the allowable action range of the resonance condition against a frequency of the high frequency current and against inductance of the high frequency coil. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ICP (Inductively Coupled Plasma) circuit, a plasma processing apparatus, and a plasma processing method, and more particularly to an ICP circuit, a plasma processing apparatus, and a plasma processing method that stably generate high-density plasma.

As a typical conventional plasma processing apparatus, an apparatus that generates plasma of a processing gas by high frequency discharge by a high frequency coil is known. Such induction-type plasma processing apparatuses are roughly classified into a type in which the high-frequency coil is disposed outside the vacuum vessel and a type in which the high-frequency coil is disposed inside.
In the former case, when the vacuum vessel is formed of a dielectric or a conductor such as metal, it is necessary to interpose a dielectric layer for insulation between the vacuum vessel and the high frequency coil. . As a result, since a vacuum vessel exists between the high-frequency coil and the plasma, the coupling between them becomes weak and the plasma generation efficiency is lowered. Further, as described above, even if the vacuum container is formed of a dielectric material, for example, it is formed of a metal, a dielectric layer is required, which is not economical.

  As an example of the latter, that is, a plasma processing apparatus of a type in which a high-frequency coil is disposed in a vacuum vessel, a vacuum vessel in which an object to be processed that is processed using plasma is accommodated and at least a part is formed of a conductive material. A means for supplying a processing gas into the vacuum vessel, a one-turn coil disposed in the vacuum vessel for generating plasma of the processing gas, and a power supply circuit for supplying a high-frequency current to the one-turn coil The power supply circuit has a balun circuit so as to prevent a high-frequency current from flowing from the high-frequency coil to the vacuum vessel. The balun circuit includes a ring-shaped magnetic body, and a primary coil and a secondary coil wound around the magnetic body. These coils are wound in opposite directions with substantially the same number of turns so that the current flowing through the primary coil and the current flowing through the secondary coil cancel each other out (see, for example, Patent Documents). 1).

JP 11-307299 A (second, fifth, eleventh paragraphs, FIGS. 4 to 5)

  By the way, in the case of the former type in which the high-frequency coil is arranged outside the vacuum vessel, the vacuum vessel is formed by a quartz chamber. However, since the quartz chamber is easily broken, there is a limit to increasing the size of the chamber. For example, when a plasma processing apparatus is used as a sputtering apparatus, a large chamber is required because a sputtering target disposed in the chamber is large, and thus a quartz chamber is not suitable.

  Further, the latter type in which the high-frequency coil is disposed in the vacuum vessel uses a balun circuit, and therefore circuit adjustment is very difficult.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ICP circuit, a plasma processing apparatus, and a plasma processing method that can easily adjust a circuit and stably generate a high-density plasma. There is.

In order to solve the above problems, an ICP circuit according to the present invention is an ICP circuit that performs circuit operation in a resonance condition or an allowable operation range of the resonance condition,
A coil to which a high-frequency current is supplied;
A high frequency power source connected to one end of the coil and outputting the high frequency current;
A resonance capacitor connected to the other end of the coil and having a capacity that satisfies a resonance condition or an allowable operation range of the resonance condition with respect to a frequency of the high-frequency current and an inductance of the coil;
It is characterized by comprising.
An ICP circuit according to the present invention is an ICP circuit that performs circuit operation in a resonance condition or an allowable operation range of the resonance condition,
A coil to which a high-frequency voltage is supplied;
A high-frequency power source connected in parallel to the coil and outputting the high-frequency voltage;
A resonance capacitor connected in parallel to the coil and having a capacity that satisfies a resonance condition or an allowable operating range of the resonance condition with respect to the frequency of the high-frequency voltage and the inductance of the coil;
It is characterized by comprising.

A plasma processing apparatus according to the present invention is a plasma processing apparatus for processing an object to be processed by generating inductively coupled plasma in a resonance condition or an allowable operation range of the resonance condition,
A processing chamber;
A holding mechanism that is disposed in the processing chamber and holds an object to be processed;
A gas introduction mechanism for introducing gas into the processing chamber;
A coil disposed in the processing chamber and supplied with a high-frequency current;
A high frequency power source connected to one end of the coil and outputting the high frequency current;
A resonance capacitor connected to the other end of the coil and having a capacity that satisfies a resonance condition or an allowable operation range of the resonance condition with respect to a frequency of the high-frequency current and an inductance of the coil;
It is characterized by comprising.

  According to the above-described plasma processing apparatus, high-density inductively coupled plasma can be stably generated by performing circuit operation within the resonance condition or the allowable operation range of the resonance condition.

In the plasma processing apparatus according to the present invention, the allowable operating range of the resonance condition is that the frequency of the high-frequency current is f (unit: Hz), the inductance of the coil is a (unit: H), and the resonance capacitor When the capacity of is b (unit: F), it is preferably in a range satisfying the following formula.
0.9 / (2πf) ² a ≦ b ≦ 1.1 / (2πf) ² a
A plasma processing apparatus according to the present invention is a plasma processing apparatus for processing an object to be processed by generating inductively coupled plasma in a resonance condition or an allowable operation range of the resonance condition,
A processing chamber;
A holding mechanism that is disposed in the processing chamber and holds an object to be processed;
A gas introduction mechanism for introducing gas into the processing chamber;
A coil disposed in the processing chamber and supplied with a high-frequency voltage;
A high-frequency power source connected in parallel to the coil and outputting the high-frequency voltage;
A resonance capacitor connected in parallel to the coil and having a capacity that satisfies a resonance condition or an allowable operating range of the resonance condition with respect to the frequency of the high-frequency voltage and the inductance of the coil;
It is characterized by comprising.

A plasma processing apparatus according to the present invention is a plasma processing apparatus for processing an object to be processed by generating inductively coupled plasma in a resonance condition or an allowable operation range of the resonance condition,
A processing chamber;
A holding mechanism that is disposed in the processing chamber and holds an object to be processed;
A gas introduction mechanism for introducing gas into the processing chamber;
A coil disposed in the processing chamber and supplied with a high-frequency current;
A high frequency power source connected to one end of the coil and outputting the high frequency current;
A variable capacitor connected to the other end of the coil;
An ammeter for measuring a high-frequency current flowing in the coil;
Comprising
During processing, the ammeter measures the high-frequency current flowing in the coil, and from this measurement result, the capacitance satisfies the resonance condition or the allowable operating range of the resonance condition for the frequency of the high-frequency current and the inductance of the coil. The variable capacitor is adjusted as follows.

  According to the plasma processing apparatus, during the processing, the variable capacitor is adjusted so as to satisfy a capacity satisfying the resonance condition or the allowable operating range of the resonance condition, thereby being out of the allowable operating range of the resonance condition or the resonance condition. And high-density plasma treatment can be performed more stably.

In the plasma processing apparatus according to the present invention, the allowable operating range of the resonance condition is that the frequency of the high-frequency current is f (unit: Hz), the inductance of the coil is a (unit: H), and the variable capacitor When the capacity of is b (unit: F), it is preferably in a range satisfying the following formula.
0.9 / (2πf) ² a ≦ b ≦ 1.1 / (2πf) ² a
A plasma processing apparatus according to the present invention is a plasma processing apparatus for processing an object to be processed by generating inductively coupled plasma in a resonance condition or an allowable operation range of the resonance condition,
A processing chamber;
A holding mechanism that is disposed in the processing chamber and holds an object to be processed;
A gas introduction mechanism for introducing gas into the processing chamber;
A coil disposed in the processing chamber and supplied with a high-frequency voltage;
A high-frequency power source connected in parallel to the coil and outputting the high-frequency voltage;
A variable capacitor connected in parallel to the coil;
A voltmeter for measuring a high-frequency voltage applied to the coil;
Comprising
During processing, a high-frequency voltage applied to the coil is measured by the voltmeter, and a capacitance satisfying a resonance condition or an allowable operating range of the resonance condition with respect to the frequency of the high-frequency voltage and the inductance of the coil from the measurement result. The variable capacitor is adjusted so that

In the plasma processing apparatus according to the present invention, the coil is preferably a one-turn coil.
In the plasma processing apparatus according to the present invention, the one-turn coil is preferably covered with a ceramic film.

The plasma processing apparatus according to the present invention may further include a power source for supplying a high frequency current or a direct current to the object to be processed.
In the plasma processing apparatus according to the present invention, the gas may be a CVD source gas containing an organic metal.

The plasma processing method according to the present invention holds an object to be processed in a processing chamber,
While introducing a gas into the processing chamber, a high-frequency current is supplied to a coil of an ICP circuit disposed in the processing chamber, thereby generating inductively coupled plasma of the gas within a resonance condition or an allowable operating range of the resonance condition. A method of plasma processing the object to be processed,
The ICP circuit is:
A coil to which a high-frequency current is supplied;
A high frequency power source connected to one end of the coil and outputting the high frequency current;
And a resonance capacitor connected to the other end of the coil and having a capacity satisfying a resonance condition or an allowable operation range of the resonance condition with respect to the frequency of the high-frequency current and the inductance of the coil.

In the plasma processing method according to the present invention, the allowable operating range of the resonance condition is that the frequency of the high-frequency current is f (unit: Hz), the inductance of the coil is a (unit: H), and the resonance capacitor When the capacity of is b (unit: F), it is preferably in a range satisfying the following formula.
0.9 / (2πf) ² a ≦ b ≦ 1.1 / (2πf) ² a
The plasma processing method according to the present invention holds an object to be processed in a processing chamber,
While introducing a gas into the processing chamber, an inductively coupled plasma of the gas is generated within a resonance condition or an allowable operating range of the resonance condition by supplying a high frequency voltage to a coil of an ICP circuit disposed in the processing chamber. A method of plasma processing the object to be processed,
The ICP circuit is:
A coil to which a high-frequency voltage is supplied;
A high-frequency power source connected in parallel to the coil and outputting the high-frequency voltage;
And a resonance capacitor connected in parallel to the coil and having a capacity satisfying a resonance condition or an allowable operation range of the resonance condition with respect to a frequency of the high-frequency voltage and an inductance of the coil.

The plasma processing method according to the present invention holds an object to be processed in a processing chamber,
While introducing a gas into the processing chamber, a high-frequency current is supplied to a coil of an ICP circuit disposed in the processing chamber, thereby generating inductively coupled plasma of the gas within a resonance condition or an allowable operating range of the resonance condition. A method of plasma processing the object to be processed,
When plasma-treating the object to be processed, a high-frequency current flowing in the coil is measured, and based on the measurement result, a resonance condition or an allowable operating range of the resonance condition is satisfied with respect to the frequency of the high-frequency current and the inductance of the coil. The variable capacitor of the ICP circuit is adjusted so as to have a capacity,
The ICP circuit is:
A coil to which a high-frequency current is supplied;
A high frequency power source connected to one end of the coil and outputting the high frequency current;
And a variable capacitor connected to the other end of the coil.
The plasma processing method according to the present invention holds an object to be processed in a processing chamber,
While introducing a gas into the processing chamber, an inductively coupled plasma of the gas is generated within a resonance condition or an allowable operating range of the resonance condition by supplying a high frequency voltage to a coil of an ICP circuit disposed in the processing chamber. A method of plasma processing the object to be processed,
When the object to be processed is subjected to plasma treatment, a high frequency voltage applied to the coil is measured, and from this measurement result, a resonance condition or an allowable operation range of the resonance condition is determined for the frequency of the high frequency voltage and the inductance of the coil. The variable capacitor of the ICP circuit is adjusted so as to satisfy the capacity,
The ICP circuit is:
A coil to which a high-frequency current is supplied;
A high-frequency power source connected in parallel to the coil and outputting the high-frequency voltage;
And a variable capacitor connected in parallel to the coil.

  As described above, according to the present invention, it is possible to provide an ICP circuit, a plasma processing apparatus, and a plasma processing method that can easily adjust a circuit and stably generate a high-density plasma.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment 1)
FIG. 1 is a block diagram schematically showing a plasma processing apparatus according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of the plasma processing apparatus shown in FIG. FIG. 3 is a cross-sectional view taken along line 3-3 shown in FIG.

  The plasma processing apparatus shown in FIG. 1 has a vacuum vessel 10 as a processing chamber formed of a conductive material made of a metal such as stainless steel or aluminum. A gas supply port 11 for supplying a processing gas into the vacuum vessel 10 is provided in a part of the peripheral wall of the vacuum vessel 10. The gas supply port 11 is connected to a processing gas source (not shown), for example, an etching gas source.

  An electric insulating plate 12 is mounted on the inner surface of the bottom wall of the vacuum vessel 10, and a susceptor 14 for placing an object to be processed, for example, a semiconductor wafer 13, is attached to the vacuum vessel 10. Are electrically insulated. The shape of the upper surface of the susceptor 14 (the mounting surface on which the semiconductor wafer is mounted) is substantially circular. Further, an exhaust port 15 is provided on the bottom wall of the vacuum vessel 10 so that the inside of the vacuum vessel can be reduced to a constant pressure. The exhaust port 15 is connected to a vacuum device such as a vacuum pump (not shown).

  A high frequency power source (RF) 22 is connected to the susceptor 14 via a matching box 21. A high frequency current is applied to the semiconductor wafer 13 through the susceptor 14 by the high frequency power source 22. In the present embodiment, a high-frequency current is applied to the semiconductor wafer. However, the present invention is not limited to this, and a DC power source is connected to the susceptor 14, and the DC current is applied to the semiconductor via the susceptor. It is also possible to apply to the wafer.

  A high frequency coil (ICP electrode) 16 is disposed above the susceptor 14 in the vacuum vessel 10. As shown in FIGS. 2 and 3, the high-frequency coil 16 is composed of a one-turn coil formed of a flexible member such as a metal flexible tube or a braided wire. As shown, the interior is hollow. The high-frequency coil 16 is formed by winding a coil of one turn substantially concentrically with respect to a line extending vertically from the approximate center of the surface of the semiconductor wafer placed on the susceptor 14 to the surface. In the present embodiment, the one-turn coil is used as the high-frequency coil, but the present invention is not limited to this, and the turn coil can be used a plurality of times as the high-frequency coil. It is also possible to use a modified version.

The high frequency coil 16 is covered with a sheath 19 made of ceramics so as not to be directly exposed to the processing gas in the vacuum vessel 10. Inside the vacuum vessel 10, a sheath 19 is disposed substantially coaxially with a perpendicular line from the approximate center of the surface of the semiconductor wafer placed on the susceptor 14, and the high-frequency coil 16 is inserted into the sheath 19. . The ceramic sheath 19 is preferably formed of a material that is chemically stable and has a low sputtering rate due to ion bombardment, such as fused quartz or alumina.
In the present embodiment, the high-frequency coil 16 is covered with the sheath 19 made of ceramics. However, the high-frequency coil can be covered with a ceramic film.

  In order to accommodate the high-frequency coil 16 in the ceramic sheath 19, for example, as described above, the high-frequency coil 16 is formed of a flexible member, and the sheath 19 formed in advance has a high frequency. The coil 16 may be inserted. Alternatively, a ceramic material may be applied to the surface of the high frequency coil 16 and sintered. If the sheath 19 is in contact with the high-frequency coil 16, there is a risk that electric discharge will occur and breakage. Therefore, the inner diameter of the sheath 19 is adjusted so that the inner surface of the sheath does not contact the outer surface of the high-frequency coil 16. It is preferable to set a little larger than this.

  In the present embodiment, in order to prevent the high-frequency coil 16 from being excessively heated during use, the inside of the high-frequency coil 16 is hollow as described above, and the inside of the high-frequency coil 16 is filled with a refrigerant, for example, cooling water. Can be circulated.

  As shown in FIGS. 2 and 3, one end of the high-frequency coil 16 is connected to an ICP power source 18 via a matching box 17. The other end of the high frequency coil 16 is connected to the ground potential via the resonance capacitor 20. The resonance capacitor 20 has a capacity that satisfies a resonance condition or an allowable operating range of the resonance condition with respect to the frequency of the high-frequency current output from the ICP power supply 18 and the inductance of the high-frequency coil 16.

  That is, for example, when a high frequency current having a frequency of 13.56 MHz is supplied to the high frequency coil 16 via the matching box 17 by the ICP power source 18, the high frequency current flows through the high frequency coil under a resonance condition. In this case, the maximum current is obtained. When such a maximum high-frequency current flows through the high-frequency coil 16, a large magnetic field is generated from the high-frequency coil 16, and a large electric field is generated inside the high-frequency coil by this magnetic field. As a result, inductively coupled plasma of the processing gas can be generated at a very high density inside and in the vicinity of the high frequency coil located above the semiconductor wafer 13 in the vacuum vessel 10.

In other words, an important feature of the present embodiment is that a one-turn coil (one-turn coil) is placed in a vacuum container that is decompressed, and a resonance capacitor is connected in series with the one-turn coil so that it resonates at the operating frequency. In order to construct a resonance circuit (ICP circuit) in which those constants (inductance of one-turn coil, frequency of high-frequency current, capacity of resonance capacitor) are selected, engineering advantages such as the following (1) and (2) Have
(1) The stray capacitance of the coil is extremely small, and capacitive coupling discharge (CCD) that occurs at the beginning of discharge can be almost ignored, and plasma is generated by inductive coupling discharge (ICD). For this reason, the plasma is stable and dense.
(2) The magnetic coupling between the coil and the generated plasma is strong, the Q value (described later) of the resonance circuit is low, the tolerance of the circuit constant is loose, and the circuit operation is stable despite being a simple circuit. It is easy to drive.

  In addition, when the capacity of the resonant capacitor is set within the allowable operating range of the resonance condition, when the high frequency current is supplied to the high frequency coil, the high frequency current flows through the high frequency coil under conditions close to the resonance condition. The current is close to the maximum current. Accordingly, in this case as well, inductively coupled plasma of the processing gas can be generated at a high density inside and in the vicinity of the high frequency coil. The resonance conditions and the allowable operating range of the resonance conditions will be described below.

In order to achieve the resonance condition, the frequency of the ICP power supply 18 is set to f (unit: Hz), the inductance of the high frequency coil is set to a (unit: H (Henry)), and the capacitance of the resonance capacitor is set to b (unit: F (farad). )), The following formula (1) needs to be satisfied.
ω = 2πf = (ab) ^−1/2 (1)

From the above formula (1), the following formula (2) is established.
b = 1 / (2πf) ² a (2)
Therefore, the capacitance b of the resonant capacitor 20 that achieves the resonance condition needs to be set to 1 / (2πf) ² a.

Regarding the above formula (1), when taking the natural logarithm of both sides,
ln2π + lnf = −1 / 2 (lna + lnb)
Taking the derivative of both sides,
δf / f = −1 / 2 (δa / a + δb / b)
If the absolute values of both sides are taken, the sign of the right side becomes +.
Therefore, if δa / a = δb / b = 0.1,
δf / f = 0.1, which corresponds to a Q value of 10.
Therefore, a maximum of 10% error between the coil and the capacitor is allowed.

If the coupling between the high-frequency coil and the plasma is sufficiently improved as in the above calculation, it is considered that the inductance error of the high-frequency coil and the capacitance error of the resonance capacitor can be sufficiently large. This error is considered acceptable. Therefore, if the error of 10% is equally distributed to the errors of the high frequency coil 16 and the resonance capacitor 20, it is considered that the error of the resonance capacitor can be tolerated by 10%. Therefore, the capacitance b of the resonant capacitor 20 can be set in the range of the following formula (3), and more preferably in the range of the following formula (4).
0.9 / (2πf) ² a ≦ b ≦ 1.1 / (2πf) ² a (3)
0.95 / (2πf) ² a ≦ b ≦ 1.05 / (2πf) ² a (4)

A description will be given with specific examples in the above formulas (2) and (4). For example, when f = 13.56 MHz and a = 1 μH, as shown below, it is preferable that the capacitance of the resonant capacitor be in the range of 131.1 pF to 144.9 pF, and the more preferable resonant capacitor is 138 pF. Yes, it is easy to obtain such a resonant capacitor.
b = 1 / (6.28 × 13.56 × E6) ² × 1 × E-6
= 1.38 × 10 ⁻¹⁰ (farad)
= 138pF
b (lower limit value) = 138 × 0.95
= 131.1pF
b (upper limit value) = 138 × 1.05
= 144.9 pF

  In the plasma processing apparatus having the above-described configuration, for example, an etching gas is supplied as a processing gas into the vacuum vessel 10, and a high-frequency current is supplied to the ICP electrode 16, so that the plasma generated by the etching gas is supplied to the semiconductor wafer 13. While being generated upward, a high frequency current is applied to the semiconductor wafer to apply a bias to the semiconductor wafer, whereby the wafer is etched by ions, radicals, and the like generated by the high-density plasma.

  When the plasma processing apparatus is used as a plasma CVD (chemical vapor deposition) apparatus, for example, a raw material gas containing an organic metal is used as a processing gas, and the raw material gas is supplied into a vacuum vessel 10 having a reduced pressure, and a high-frequency coil is supplied. The high-density current is applied to the semiconductor wafer by applying a high-frequency current to the semiconductor wafer while stably generating a high-density plasma above the semiconductor wafer by applying a high-frequency current to the semiconductor wafer. Film formation by the CVD method is performed.

  In the case of using a source gas containing an organic metal, the conventional plasma CVD apparatus usually has a low film formation rate because it is not easy to decompose the organic metal. In contrast, the plasma CVD apparatus according to this embodiment can generate high-density inductively coupled plasma, so that the organic metal can be easily decomposed, and as a result, the film formation rate can be increased. it can.

According to the first embodiment, when the frequency of the ICP power supply 18 is f and the inductance of the high frequency coil is a, the capacitance b of the resonance capacitor is 1 / (2πf) ² a or 0.9 / (2πf) ² a ≦ b ≦ 1.1 / (2πf) ² a. Thereby, resonance can be caused when a high-frequency current is supplied to the high-frequency coil 16, whereby the high-frequency current value becomes close to the maximum, and high-density inductively coupled plasma can be stably generated. Therefore, uniform plasma processing can be performed on the semiconductor wafer as the object to be processed.

In the present embodiment, since the high-frequency coil is a one-turn coil, the size of the plasma processing apparatus can be reduced, and space saving can be realized. In addition, the use of a one-turn coil makes it easier to control the plasma as compared to the case of using a coil wound a plurality of times.
Further, the ICP circuit of the present embodiment is easier to adjust than the balun circuit used in the conventional plasma processing apparatus.

  In the present embodiment, since a high frequency current is applied to a semiconductor wafer as an object to be processed and a bias is applied to the semiconductor wafer, the quality of a film formed by, for example, a plasma CVD method can be improved. That is, the formed film becomes dense and the film quality can be improved.

  In the present embodiment, the high frequency coil 16 is covered with a sheath 19 made of ceramics to prevent the high frequency coil from being directly exposed to the processing gas. As a result, it is possible to prevent the high frequency coil from being exposed to the plasma generated in the vacuum vessel. Therefore, it is possible to prevent the high frequency coil from being sputtered by particles generated by plasma. As a result, a more uniform process free of impurities can be performed on the semiconductor wafer as the object to be processed. In addition, the life of the high frequency coil is extended.

  Next, by using the plasma processing apparatus shown in FIG. 1 as a plasma CVD apparatus, an experiment was performed in which a DLC (diamond like carbon) film was formed on a substrate and the hardness of the DLC film was measured. Hereinafter, film forming conditions and measurement results will be described.

The substrate of SUS304 is held on the susceptor 14, the temperature of the substrate is heated to 150 ° C., toluene (C ₆ H ₅ CH ₃ ) is introduced as a source gas into the processing chamber, the RF output of the high frequency power supply 22 is set to 200 W, 13 A plasma was generated on the substrate by setting the output of the .56 MHz ICP power supply 18 to 300 W, and a DLC film was formed on the substrate by plasma CVD. The film formation time was 60 minutes. The capacity of the resonance capacitor was 138 pF. The hardness of the DLC film formed under such film forming conditions was measured using a Knoop micro hardness tester with a load of 10 gf. The measurement result was 1700HK.

  Further, a DLC film was formed on the substrate under the same conditions as those described above except that the output of the ICP power supply 18 was set to 0 W. The hardness of this DLC film was measured by the same method as described above. The measurement result was 1240HK.

  In the above experiment, the change in hardness of the formed DLC film was examined depending on whether the RF bias to the substrate was fixed at 200 W and the ICP output was set to 0 W or 300 W. It was confirmed that a hard DLC film can be formed when the ICP output is 300 W compared to 0 W. It is considered that the DLC film has a dense film structure when the hardness is higher. Therefore, it can be said that the film quality can be improved by applying the ICP output to the ICP electrode.

(Embodiment 2)
FIG. 4 is a cross-sectional view showing the main part of the plasma processing apparatus according to the second embodiment of the present invention, and is a cross-sectional view of the plasma processing apparatus shown in FIG. . 4, the same parts as those in FIG. 2 are denoted by the same reference numerals, and only the parts different from the first embodiment will be described.

  In the present embodiment, instead of the resonant capacitor of the plasma processing apparatus according to the first embodiment, a variable capacitor 20a is attached and an ammeter 23 for measuring the high-frequency current flowing through the high-frequency coil 16 is added.

  Specifically, a variable capacitor 20a is connected to the other end of the high-frequency coil 16, and an ammeter 23 is connected to the variable capacitor 20a. The ammeter 23 is connected to the ground potential. The value of the high-frequency current flowing through the high-frequency coil 16 measured by the ammeter 23 is fed back to the variable capacitor 20a, and the variable capacitor 20a is controlled as follows by a control unit (not shown).

  In a plasma processing apparatus, a processing gas is introduced into a vacuum vessel, a high-frequency current is supplied to a high-frequency coil, and plasma processing is performed by generating inductively coupled plasma of the gas within a resonance condition or an allowable operating range of the resonance condition. Depending on the processing conditions such as the pressure in the vacuum vessel and the type of processing gas, the coupling state between the high-frequency coil and the surrounding atmosphere becomes dense, and the equivalent of the high-frequency coil including inductance such as gas around the high-frequency coil Inductance may vary. In this case, the resonance condition also varies. Therefore, the current value flowing through the high-frequency coil 16 being processed is measured by the ammeter 23, the deviation of the resonance condition is detected from the measured current value, and the detection result is fed back to the variable capacitor 20a so as to approach the resonance condition. The capacity of the variable capacitor 20a is adjusted. Accordingly, it is possible to prevent the resonance condition or the allowable operation range of the resonance condition from being deviated, and to perform the plasma treatment with higher density and stability.

(Embodiment 3)
FIG. 5 is a cross-sectional view showing the main part of the plasma processing apparatus according to Embodiment 3 of the present invention, and is a cross-sectional view of the plasma processing apparatus shown in FIG. . In FIG. 5, the same parts as those in FIG. 2 are denoted by the same reference numerals, and only different parts from the first embodiment will be described.

  A matching box 17 is connected in parallel to the high-frequency coil 16. Further, an ICP power source 18 for applying a high frequency voltage is connected in parallel to the high frequency coil. A resonance capacitor 20b is connected in parallel to the high frequency coil. A voltmeter 24 is connected in parallel to the high frequency coil. The resonant capacitor 20b has a capacity that satisfies the resonance condition or the allowable operating range of the resonance condition with respect to the frequency of the high-frequency voltage output from the ICP power supply 18 and the inductance of the high-frequency coil 16.

  That is, for example, when a high frequency voltage having a frequency of 13.56 MHz is supplied to the high frequency coil 16 via the matching box 17 by the ICP power source 18, the high frequency voltage flows through the high frequency coil under a resonance condition. In this case, the maximum voltage is obtained. When such a maximum high frequency voltage is applied to the high frequency coil 16, a large magnetic field is generated from the high frequency coil 16, and a large electric field is generated inside the high frequency coil by this magnetic field. As a result, inductively coupled plasma of the processing gas can be generated at a very high density inside and in the vicinity of the high frequency coil located above the semiconductor wafer 13 in the vacuum vessel 10.

(Embodiment 4)
In the present embodiment, only parts different from the third embodiment will be described.
In this embodiment, a variable capacitor is attached instead of the resonance capacitor 20b of the plasma processing apparatus according to the third embodiment. Furthermore, the value of the high frequency voltage applied to the high frequency coil 16 measured by the voltmeter 24 is fed back to the variable capacitor, and the variable capacitor is controlled as follows by a control unit (not shown).

  In a plasma processing apparatus, a processing gas is introduced into a vacuum vessel, a high-frequency voltage is supplied to a high-frequency coil, and plasma treatment is performed by generating inductively coupled plasma of the gas within a resonance condition or an allowable operating range of the resonance condition. Depending on the processing conditions such as the pressure in the vacuum vessel and the type of processing gas, the coupling state between the high-frequency coil and the surrounding atmosphere becomes dense, and the equivalent of the high-frequency coil including inductance such as gas around the high-frequency coil Inductance may vary. In this case, the resonance condition also varies. Therefore, the voltage value applied to the high-frequency coil 16 being processed is measured by the voltmeter 24, the deviation of the resonance condition is detected from the measured voltage value, and the detection result is fed back to the variable capacitor to approximate the resonance condition. Adjust the capacitance of the variable capacitor so that Accordingly, it is possible to prevent the resonance condition or the allowable operation range of the resonance condition from being deviated, and to perform the plasma treatment with higher density and stability.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, the etching apparatus and the plasma CVD apparatus are described as examples of the plasma processing apparatus. However, the present invention is described as another apparatus, for example, another film forming apparatus or an apparatus for coating or ashing. It is also possible to apply.

It is a block diagram which shows schematically the plasma processing apparatus by embodiment of this invention. It is sectional drawing which looked at the plasma processing apparatus shown in FIG. 1 from the 2-2 line direction. FIG. 3 is a cross-sectional view taken along line 3-3 shown in FIG. It is sectional drawing which shows the principal part of the plasma processing apparatus by Embodiment 2 of this invention. It is sectional drawing which shows the principal part of the plasma processing apparatus by Embodiment 3 of this invention.

Explanation of symbols

10 ... Vacuum container 11 ... Gas supply port 12 ...
13 ... Semiconductor wafer 14 ... Susceptor 15 ... Exhaust port 16 ... High frequency coil (ICP electrode)
17, 21 ... Matching box 18 ... ICP power supply 19 ... Sheath 20, 20b ... Resonance capacitor 20a ... Variable capacitor 22 ... High frequency power supply (RF)
23 ... Ammeter 24 ... Voltmeter

Claims (17)

An ICP circuit that performs a circuit operation within a resonance condition or an allowable operation range of the resonance condition,
A coil to which a high-frequency current is supplied;
A high frequency power source connected to one end of the coil and outputting the high frequency current;
A resonance capacitor connected to the other end of the coil and having a capacity that satisfies a resonance condition or an allowable operation range of the resonance condition with respect to a frequency of the high-frequency current and an inductance of the coil;
An ICP circuit comprising: An ICP circuit that performs a circuit operation within a resonance condition or an allowable operation range of the resonance condition,
A coil to which a high-frequency voltage is supplied;
A high-frequency power source connected in parallel to the coil and outputting the high-frequency voltage;
A resonance capacitor connected in parallel to the coil and having a capacity that satisfies a resonance condition or an allowable operating range of the resonance condition with respect to the frequency of the high-frequency voltage and the inductance of the coil;
An ICP circuit comprising: A plasma processing apparatus for processing an object to be processed by generating inductively coupled plasma in a resonance condition or an allowable operation range of a resonance condition,
A processing chamber;
A holding mechanism that is disposed in the processing chamber and holds an object to be processed;
A gas introduction mechanism for introducing gas into the processing chamber;
A coil disposed in the processing chamber and supplied with a high-frequency current;
A high frequency power source connected to one end of the coil and outputting the high frequency current;
A resonance capacitor connected to the other end of the coil and having a capacity that satisfies a resonance condition or an allowable operation range of the resonance condition with respect to a frequency of the high-frequency current and an inductance of the coil;
A plasma processing apparatus comprising: 4. The allowable operating range of the resonance condition according to claim 3, wherein the frequency of the high-frequency current is f (unit: Hz), the inductance of the coil is a (unit: H), and the capacitance of the resonance capacitor is b (unit). : F), the plasma processing apparatus is in a range satisfying the following formula:
0.9 / (2πf) ² a ≦ b ≦ 1.1 / (2πf) ² a A plasma processing apparatus for processing an object to be processed by generating inductively coupled plasma in a resonance condition or an allowable operation range of a resonance condition,
A processing chamber;
A holding mechanism that is disposed in the processing chamber and holds an object to be processed;
A gas introduction mechanism for introducing gas into the processing chamber;
A coil disposed in the processing chamber and supplied with a high-frequency voltage;
A high-frequency power source connected in parallel to the coil and outputting the high-frequency voltage;
A resonance capacitor connected in parallel to the coil and having a capacity that satisfies a resonance condition or an allowable operating range of the resonance condition with respect to the frequency of the high-frequency voltage and the inductance of the coil;
A plasma processing apparatus comprising: A plasma processing apparatus for processing an object to be processed by generating inductively coupled plasma in a resonance condition or an allowable operating range of a resonance condition,
A processing chamber;
A holding mechanism that is disposed in the processing chamber and holds an object to be processed;
A gas introduction mechanism for introducing gas into the processing chamber;
A coil disposed in the processing chamber and supplied with a high-frequency current;
A high frequency power source connected to one end of the coil and outputting the high frequency current;
A variable capacitor connected to the other end of the coil;
An ammeter for measuring a high-frequency current flowing in the coil;
Comprising
During processing, the ammeter measures the high-frequency current flowing in the coil, and from this measurement result, the capacitance satisfies the resonance condition or the allowable operating range of the resonance condition for the frequency of the high-frequency current and the inductance of the coil. The plasma processing apparatus is characterized in that the variable capacitor is adjusted. 7. The allowable operation range of the resonance condition according to claim 6, wherein the frequency of the high-frequency current is f (unit: Hz), the inductance of the coil is a (unit: H), and the capacitance of the variable capacitor is b (unit). : F), the plasma processing apparatus is in a range satisfying the following formula:
0.9 / (2πf) ² a ≦ b ≦ 1.1 / (2πf) ² a A plasma processing apparatus for processing an object to be processed by generating inductively coupled plasma in a resonance condition or an allowable operating range of a resonance condition,
A processing chamber;
A holding mechanism that is disposed in the processing chamber and holds an object to be processed;
A gas introduction mechanism for introducing gas into the processing chamber;
A coil disposed in the processing chamber and supplied with a high-frequency voltage;
A high-frequency power source connected in parallel to the coil and outputting the high-frequency voltage;
A variable capacitor connected in parallel to the coil;
A voltmeter for measuring a high-frequency voltage applied to the coil;
Comprising
During processing, a high frequency voltage applied to the coil is measured by the voltmeter, and a capacitance satisfying a resonance condition or an allowable operating range of the resonance condition with respect to the frequency of the high frequency voltage and the inductance of the coil from the measurement result. The plasma processing apparatus is characterized in that the variable capacitor is adjusted so that   The plasma processing apparatus according to claim 3, wherein the coil is a one-turn coil.   The plasma processing apparatus according to claim 9, wherein the one-turn coil is covered with a ceramic film.   The plasma processing apparatus according to claim 3, further comprising a power source that supplies a high-frequency current or a direct current to the object to be processed.   12. The plasma processing apparatus according to claim 3, wherein the gas is a CVD source gas containing an organic metal. Hold the workpiece in the processing chamber,
While introducing a gas into the processing chamber, a high-frequency current is supplied to a coil of an ICP circuit disposed in the processing chamber, thereby generating inductively coupled plasma of the gas within a resonance condition or an allowable operating range of the resonance condition. A method of plasma processing the object to be processed,
The ICP circuit is:
A coil to which a high-frequency current is supplied;
A high frequency power source connected to one end of the coil and outputting the high frequency current;
And a resonance capacitor connected to the other end of the coil and having a capacity satisfying a resonance condition or an allowable operating range of the resonance condition with respect to a frequency of the high-frequency current and an inductance of the coil. Method. 14. The allowable operating range of the resonance condition according to claim 13, wherein the frequency of the high-frequency current is f (unit: Hz), the inductance of the coil is a (unit: H), and the capacitance of the resonance capacitor is b (unit). : F), a plasma processing method characterized by being in a range satisfying the following formula:
0.9 / (2πf) ² a ≦ b ≦ 1.1 / (2πf) ² a Hold the workpiece in the processing chamber,
While introducing a gas into the processing chamber, an inductively coupled plasma of the gas is generated within a resonance condition or an allowable operating range of the resonance condition by supplying a high frequency voltage to a coil of an ICP circuit disposed in the processing chamber. A method of plasma processing the object to be processed,
The ICP circuit is:
A coil to which a high-frequency voltage is supplied;
A high-frequency power source connected in parallel to the coil and outputting the high-frequency voltage;
And a resonance capacitor connected in parallel to the coil and having a capacity satisfying a resonance condition or an allowable operation range of the resonance condition with respect to the frequency of the high-frequency voltage and the inductance of the coil. . Hold the workpiece in the processing chamber,
While introducing a gas into the processing chamber, a high-frequency current is supplied to a coil of an ICP circuit disposed in the processing chamber, thereby generating inductively coupled plasma of the gas within a resonance condition or an allowable operating range of the resonance condition. A method of plasma processing the object to be processed,
When plasma-treating the object to be processed, a high-frequency current flowing in the coil is measured, and based on the measurement result, a resonance condition or an allowable operating range of the resonance condition is satisfied with respect to the frequency of the high-frequency current and the inductance of the coil. The variable capacitor of the ICP circuit is adjusted so as to have a capacity,
The ICP circuit is:
A coil to which a high-frequency current is supplied;
A high frequency power source connected to one end of the coil and outputting the high frequency current;
A plasma processing method comprising: a variable capacitor connected to the other end of the coil. Hold the workpiece in the processing chamber,
While introducing a gas into the processing chamber, an inductively coupled plasma of the gas is generated within a resonance condition or an allowable operating range of the resonance condition by supplying a high frequency voltage to a coil of an ICP circuit disposed in the processing chamber. A method of plasma processing the object to be processed,
When the object to be processed is subjected to plasma treatment, a high frequency voltage applied to the coil is measured, and from this measurement result, a resonance condition or an allowable operation range of the resonance condition is determined for the frequency of the high frequency voltage and the inductance of the coil. The variable capacitor of the ICP circuit is adjusted so as to satisfy the capacity,
The ICP circuit is:
A coil to which a high-frequency current is supplied;
A high-frequency power source connected in parallel to the coil and outputting the high-frequency voltage;
A plasma processing method comprising: a variable capacitor connected in parallel to the coil.

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