JPH07297175A - Method and apparatus for plasma treatment - Google Patents

Abstract

PURPOSE:To make the follow-up property of ions in a plasma good, to accelerate the ions with high efficiency even with small power and to make them impinge on an object to be treated such as a semiconductor wafer when conducting a plasma treatment to an object. CONSTITUTION:The frequency of high-frequency electric power which is applied to a susceptor 5 inside a treatment container 2 is set at a frequency which is lower than a lower-end ion transition frequency which is inherent in a treatment gas, and the frequency of high-frequency electric power which is applied to an upper-part electrode 21 is set at a frequency which is higher than an upper-end ion transition frequency which is inherent in the treatment gas. Thereby, the follow-up property of ions in a plasma can be made good.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing method and a plasma processing apparatus.

[0002]

2. Description of the Related Art Conventionally, for example, in a semiconductor manufacturing process, in order to perform a surface treatment of a semiconductor wafer (hereinafter referred to as a "wafer"), a treatment gas is introduced into the treatment chamber and the treatment gas is opposed to the treatment chamber. High frequency power is applied to the provided first electrode and second electrode to generate plasma, and the wafer in the processing chamber is subjected to predetermined processing under the plasma atmosphere, for example, etching or sputtering. The plasma processing method of applying is carried out. In the case of etching, for example, the etching gas introduced into the processing chamber is dissociated in the plasma atmosphere, and the wafer is etched by the ions generated thereby.

By the way, the processing by plasma processing is
As semiconductor devices become highly integrated, finer processing and higher processing speed are required. Therefore, it is necessary to increase the density of the plasma generated between the electrodes. However, simply increasing the frequency and increasing the density under a high vacuum will damage the object to be processed. Not preferable. In this regard, for example, power having different frequencies is applied to the first electrode and the second electrode, plasma is generated with higher frequency power, and ions are attracted with lower frequency power to control processing. Is proposed.

[Problems to be Solved by the Invention]

However, when the processing gas introduced into the processing chamber is turned into plasma, there is a difference in the movement of ions in the plasma depending on the frequency. That is, when two high and low frequencies are used, it is possible to control the ion energy and the plasma density independently, but there is a frequency region (so-called transition frequency region) in which the ion followability varies depending on the frequency. Especially, when a molecular gas is used, the followability of charged particles in the plasma sheath changes due to a change in the degree of dissociation, and various plasma characteristics such as ion current density become unstable. This makes the process itself unstable and leads to a decrease in yield. In addition, the manner of change in the following characteristics in the transition frequency region also differs depending on the ion (mass), and particularly etching and CV
In the molecular gas used in D or the like, when the electron temperature rises due to a slight increase in high-frequency power, dissociation proceeds more than necessary, and the behavior of ions in the sheath changes. And when increasing the plasma density,
As described above, there is a problem that the dissociation proceeds excessively if the frequency is simply increased, so that a suitable means for improving the plasma density is desired in places where the frequency is not high or low.

The present invention has been made in view of the above points, and a first object of the present invention is to improve the followability of ions in plasma to stabilize the plasma characteristics, and further to control the dissociation of ions. It is to accelerate the incidence and realize fine processing with high selectivity. The second purpose is to increase the plasma density without increasing the power so much,
It is to enable fine processing with little damage.

[0006]

In order to achieve the above object, according to claim 1, a processing gas is introduced into the processing chamber, and a first electrode and a second electrode are provided opposite to each other in the processing chamber. In the plasma processing method, in which high-frequency power is applied to each of the electrodes to generate plasma, and a predetermined process is performed on the object to be processed in the processing chamber under the plasma atmosphere, The frequency of the high frequency power applied is lower than the frequency of the high frequency power applied to the second electrode, and the lower ion transition frequency (LITF: Lower Ion Transit Freq) specific to the processing gas is used.
high frequency power having a frequency lower than that of the processing gas is applied to the first electrode, and high frequency power having a frequency higher than the upper ion transition frequency (UITF) inherent to the processing gas is applied to the second electrode. A plasma processing method is provided, which is characterized by applying.

In such a method, when a processing gas in which a plurality of gases are mixed is used as the processing gas, it is the lowest among the intrinsic lower end ion transition frequencies for each individual gas, as described in claim 2. A high frequency power having a frequency may be applied to the first electrode, and a high frequency power having a highest frequency among the unique upper end ion transition frequencies for each individual gas may be applied to the second electrode.

According to a third aspect of the present invention, a processing gas in which a plurality of gases are mixed is introduced into the processing chamber, and the first electrode and the second electrode provided in the processing chamber so as to face each other,
In the plasma processing method of applying a high-frequency power to each to generate plasma and subjecting an object to be processed in the processing chamber to a predetermined process in the plasma atmosphere, the high-frequency power applied to the first electrode is changed. The frequency is 1 MHz or less, and the frequency of the high frequency power applied to the second electrode is 1
A plasma processing method is provided, which is characterized in that the frequency is 0 MHz or higher.

According to the present invention, the processing gas is introduced into the processing chamber, and high-frequency power is applied to the first electrode and the second electrode facing each other in the processing chamber to form plasma. And a predetermined process is performed on the object to be processed in the processing chamber under the plasma atmosphere, in the plasma processing method, the first electrode is applied to the second electrode.
A plasma processing method is provided, characterized in that a high frequency wave having a frequency higher than the high frequency wave applied to the electrode is applied with amplitude modulation at the same frequency as the high frequency wave applied to the first electrode.

According to the fifth aspect of the present invention, the processing gas is introduced into the processing chamber, and high-frequency power is applied to the first electrode and the second electrode which are provided in the processing chamber so as to face each other. And a predetermined treatment is performed on the object to be processed in the processing chamber under the plasma atmosphere, in the plasma processing method, 100 kH is applied to the second electrode.
A high frequency power having a frequency of z to 1 MHz is applied, and a frequency of 10 MHz or more is applied to the first electrode.
There is provided a plasma processing method, characterized in that an amplitude-modulated electric power is applied at the same frequency as the high frequency applied to the electrode. Such amplitude modulation may be performed by any one of a sine wave, a triangular wave, a rectangular wave, a sawtooth wave, or a composite waveform of these, as described in claim 6.

The plasma processing apparatus provided by the present invention has, as described in claim 7, a first electrode and a second electrode facing each other in the processing chamber, and the first electrode is a matching circuit. In the plasma processing apparatus, the second electrode is connected to the relative low-frequency power source via the matching circuit, and the second electrode is connected to the high-frequency power source via the matching circuit, and between the first electrode and the matching circuit and the ground. And insert the capacitive component into the second
It is characterized in that a capacitance component and an inductive component are inserted in series between the electrode and the matching circuit thereof and the ground.

The plasma processing apparatus according to the present invention has a first electrode and a second electrode facing each other in the processing chamber, and the first electrode is provided with a relative low frequency power source through a matching circuit. And a second electrode connected to a high frequency power source through a matching circuit, wherein
The impedance component is inserted between the electrode and the matching circuit thereof to the ground so that the combined impedance for high frequency power is several Ω or less and the impedance for low frequency power is several kΩ or more. Between the electrode and its matching circuit and the ground, the combined impedance for high frequency power is several kΩ or less, and the impedance for low frequency power is several Ω or more,
It is characterized in that an impedance component including a capacitance component is inserted in series.

[0013]

According to the first aspect, since the high frequency power having a frequency lower than the lower end ion transition frequency is applied to the first electrode, the followability is good and the ions can be efficiently accelerated even with a small power. Since the ion current and the electron current are good and the ion followability is good, the current changes smoothly for both the ion current and the electron current. Further, since the followability does not change depending on the type of ions, stable processing is possible even if the degree of vacuum or the gas mixing ratio changes. On the other hand, since high frequency power having a frequency higher than the upper end ion transition frequency is applied to the second electrode, the ions do not receive the frequency in the transition region, and stable plasma can be generated. Therefore, a stable process is possible due to the combination of both.

According to a second aspect of the present invention, the process gas is a mixed gas, and the high frequency power having the lowest frequency among the individual lower end ion transition frequencies of the individual gases is the first gas.
Of the mixed gas, since the high frequency power of the highest frequency among the individual upper end ion transition frequencies of each individual gas in the process gas is applied to the second electrode. The trackability of ions is not affected by the frequency in the transition region. Therefore, the action and effect of claim 1 is directly obtained.

Generally, most of the ion transition frequency region of the processing gas used in the plasma processing in the manufacturing process of semiconductor devices such as etching, CVD and sputtering is more than 1 MHz and less than 10 MHz. Therefore, according to claim 3, the transition frequency region of each processing gas is applied to most of the processing gas as it is without checking the transition frequency region each time, and the effect of claim 1 can be obtained.

According to the fourth and fifth aspects, the processing gas is introduced into the processing chamber, and the high frequency power is applied to the first electrode and the second electrode provided facing each other in the processing chamber. In the plasma processing method, in which plasma is generated, and the object to be processed in the processing chamber is subjected to predetermined processing under the plasma atmosphere, the second electrode is applied to the first electrode. Since a high-frequency wave having a frequency higher than the high-frequency wave is applied with amplitude modulation at the same frequency as the high-frequency wave applied to the first electrode, dissociation does not proceed excessively, and at the same time ion or radical generation occurs. By controlling the phase of acceleration of the ions to the object to be processed, it is possible to generate ions and radicals necessary for the processing at the necessary timing and make them enter the object to be processed. Moreover, in order to generate plasma, the second
Since the electric power applied to the electrode is amplitude-modulated by the electric power of a lower frequency, damage to the object to be processed is reduced.

In this case, if the modulation is performed by any one of a sine wave, a triangular wave, a rectangular wave, a sawtooth wave, or a composite waveform of these, the acceleration of ions and the like can be performed. Since control is possible, it is possible to appropriately deal with various processing situations.

In general, the lower electrode on which the object to be processed is placed has therein a refrigerant reservoir (refrigerant chamber) for controlling the temperature of the object to be processed and a vertically moving object for moving the object. Various members and configurations such as a lifter and a heat transfer gas supply pipe are housed therein, and therefore, they are inductance (L) components in terms of a circuit. Therefore, when plasma is generated, the lower electrode side has a large impedance with respect to a high frequency, and it becomes difficult for current to flow to the lower electrode, and the plasma is diffused and the plasma density in the processing space becomes low in some cases.

In this respect, according to the seventh aspect, since the capacitance component is inserted between the first electrode on which the object to be processed is placed and the matching circuit thereof and the ground, the first component is inserted. The inductance (L) component of the electrode and the series resonance circuit are configured, and the impedance becomes small for high frequencies. Therefore, the current from the second electrode easily flows into the first electrode, the current density increases, and the plasma density increases. On the other hand, for the second electrode on which the object to be processed is not placed, the capacitance component and the induction component are inserted in series,
Again, the impedance is lowered with respect to the relative low frequency, the current of the relative low frequency from the first electrode side easily flows, and the controllability of ions is improved.

Also in the plasma processing apparatus according to the eighth aspect, the combined impedance for high frequency power is several Ω between the first electrode and its matching circuit and the ground.
Below, and insert the impedance component so that the impedance for the relative low frequency power is several kΩ or more,
Between the second electrode and its matching circuit and the ground, the combined impedance for high frequency power is several kΩ.
Below, and since the impedance component including the capacitance component was inserted in series so that the impedance for the relative low frequency power becomes several Ω or more, the current easily flows, the plasma density is improved, and the ion controllability is improved. improves.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 schematically shows a cross section of an etching processing apparatus 1 used for carrying out this embodiment. 1 is configured as a so-called parallel plate type etching apparatus in which electrode plates are opposed to each other in parallel.

The etching processing apparatus 1 has a processing container 2 which is formed into a cylindrical shape and is made of, for example, aluminum whose surface has been subjected to anodized aluminum oxide, and the processing container 2 is grounded. At the bottom of the processing chamber formed in the processing container 2, a substantially cylindrical column for mounting an object to be processed, for example, a semiconductor wafer (hereinafter referred to as “wafer”) W via an insulating plate 3 made of ceramic or the like. The susceptor support base 4 is housed therein, and the susceptor 5 forming a lower electrode is provided on the susceptor support base 4.

A coolant chamber 6 is provided inside the susceptor support 4, and a coolant for temperature control such as liquid nitrogen can be introduced into the coolant chamber 6 through a coolant introduction pipe 7. The introduced refrigerant circulates in the refrigerant chamber 6,
Cold heat generated during that time is transferred from the coolant chamber 6 to the wafer W via the susceptor 5, and the processing surface of the wafer W can be cooled to a desired temperature. When liquid nitrogen as described above is used as the refrigerant, the nitrogen gas generated by the nucleate boiling of the liquid nitrogen is discharged from the refrigerant discharge pipe 8 to the outside of the processing chamber 2. Inside the insulating plate 3, the susceptor support 4, and the susceptor 5, a gas passage for supplying a heat transfer medium, such as He gas, to the back surface of the wafer W, which is an object to be processed, through an electrostatic chuck 11 described later. 9 is formed, and this wafer W
Is maintained at a predetermined temperature.

The central portion of the upper surface of the susceptor 5 is formed in a convex disk shape, and an electrostatic chuck 11 having substantially the same shape as the wafer W is provided thereon. This electrostatic chuck 11
Has a structure in which the conductive layer 12 is sandwiched between two polymer polyimide films, and the conductive layer 12 is supplied from the DC high-voltage power supply 13 installed outside the processing container 2 to, for example, 1 By applying a DC high voltage of 0.5 kV, the wafer W placed on the upper surface of the electrostatic chuck 11 is attracted and held at that position by the Coulomb force.

An annular focus ring 14 is arranged around the upper edge of the susceptor 5 so as to surround the wafer W placed on the electrostatic chuck 11. The focus ring 14 is made of an insulating material that does not attract the reactive ions, and is configured so that the reactive ions generated by the plasma are effectively incident only on the wafer W inside thereof.

Above the susceptor 5, the upper electrode 21 is opposed to the susceptor 5 in parallel with the susceptor 5 at a position spaced apart from the susceptor 5 by about 15 to 20 mm, and an insulating material 22 is interposed therebetween. It is supported at the top. The upper electrode 21 has a large number of ejection holes 2 on the surface facing the susceptor 5.
3, an electrode plate 24 made of, for example, SiC or amorphous carbon, and an electrode support 25 made of a conductive material that supports the electrode plate 24, for example, aluminum whose surface is anodized.

A gas introduction port 26 is provided at the center of the support plate 25 in the upper electrode 21, and a gas introduction pipe 27 is connected to the gas introduction port 26. A gas supply pipe 28 is connected to the gas introduction pipe 27,
Further, the gas supply pipe 28 is branched into three and communicates with the corresponding process gas supply sources 35, 36 and 37 via valves 29, 30 and 31 and mass flow controllers 32, 33 and 34, respectively. . In this embodiment, the processing gas supply source 35 supplies CF ₄ gas, the processing gas supply source 36 supplies O ₂ gas, and the processing gas supply source 37 supplies N ₂ gas which is an inert purge gas. It is set.

An exhaust pipe 41 is connected to a lower portion of the processing container 2, and an exhaust pipe 44 of a load lock chamber 43 adjacent to the processing container 2 via a gate valve 42, a turbo molecular pump, and the like. It communicates with the vacuum evacuation means 45, and is configured to be capable of evacuation to a predetermined reduced pressure atmosphere. The wafer W, which is the object to be processed, is configured to be transferred between the processing container 2 and the load lock chamber 43 by the transfer means 46 such as a transfer arm provided in the load lock chamber 43. ing.

The high frequency power configuration for generating plasma in the processing container 2 of the etching processing apparatus 1 is as follows. That is, a high frequency signal from an oscillator 51 that oscillates a high frequency of 380 kHz passes through a phase controller 52 (passable), an amplifier 53 such as an RF generator, a matching device 54 including a decoupling capacitor, and a power feeding rod 55. Through processing container 2
It is configured to be applied to the susceptor 5 inside. A capacitance 56 is configured to be inserted into the power feeding rod 55 with the ground by switching the switch SW ₁ .

On the other hand, the high frequency signal from the oscillator 61 which oscillates a high frequency of 13.56 MHz can be inputted to the amplitude modulator 62, and the amplitude modulator 6
2 to pass an amplifier 63 such as an RF generator
It is also possible to input directly to. A signal from the oscillator 51 that oscillates the high frequency of 380 kHz can be freely input to the amplitude modulator 62 as a modulated wave, whereby the frequency is 13.56 M.
After the high frequency of Hz is amplitude-modulated, it can be freely applied to the upper electrode 21 in the processing container 2 through the amplifier 63 and the matching device 64 including the decoupling capacitor and the power feeding rod 65. ing.

A capacitance 66 and an inductance 67, which are connected in series, can be inserted between the power feeding rod 65 and the ground by switching the switch SW ₂ . As described above, the power supply rod 65 on the upper electrode 21 side also includes the inductance 67.
As described above, the electrostatic chuck 1 is provided on the susceptor 5 side.
1, the gas passage 9, the refrigerant chamber 6, and the above-mentioned transfer means 4
The susceptor 5 itself has a large inductance because it is thick because it includes various mechanisms such as lifter pins (not shown) for transferring the wafer W to and from the wafer 6, and the power supply rod 55 itself is long. This is because.

As described above, the upper electrode 21 and the susceptor 5 are
Since high frequency power is applied to each of the above by independent amplifiers 64 and 54, the voltages applied to the upper electrode 21 and the susceptor 5 are independently variable.

The etching processing apparatus 1 according to this embodiment is configured as described above. For example, the etching processing apparatus 1 is used to etch a silicon oxide film (SiO ₂ ) on a wafer W having a silicon substrate. The case of carrying out
After the gate valve 42 is opened, the carrier is carried into the processing container 2 from the load lock chamber 43 by the carrying means 46 and placed on the electrostatic chuck 11. Then, the wafer W is attracted and held on the electrostatic chuck 11 by the application of the high-voltage DC power supply 13. After that, the transport means 46 retracts into the load lock chamber 43, and then the inside of the processing container 2 is evacuated by the exhaust means 45.

On the other hand, while the valve 29 is opened and the flow rate thereof is adjusted by the mass flow controller 32, the CF ₄ gas from the processing gas supply source 35 is opened by the valve 30 and the flow rate thereof is adjusted by the mass flow controller 33. 1, O ₂ gas from the processing gas supply source 36 is introduced into the upper electrode 21 through the gas supply pipe 28, the gas introduction pipe 27, and the gas introduction port 26, and further through the discharge hole 23 of the electrode plate 24, as shown by the arrow in FIG. As shown, it is uniformly discharged onto the wafer W.

The pressure inside the processing container 2 is, for example, 1 P.
After being set and maintained at a, a predetermined high frequency power is applied to the susceptor 5 and the upper electrode 21 to perform a predetermined etching process. As one example of such a case, first, as shown in FIG. As shown, the switches SW ₁ and SW ₂ are separated, and the capacitance 56, and the capacitance 66 and the inductance 67 are connected to the corresponding power feeding rods 5.
Separate from 5, 56.

When the oscillator 61, the oscillator 51, the amplitude modulator 62, and the amplifiers 63 and 53 are operated in that state, the high frequency power having a waveform as shown in FIG. Plasma is generated between the susceptor 5. On the other hand, a high frequency (relative low frequency) electric power having the waveform shown in FIG. 3 is applied to the susceptor 5 by the oscillator 51 to accelerate the ions in the plasma and to generate susceptor 5.
Then, the wafer W is subjected to a predetermined etching.

In this case, since the high frequency for generating plasma has the waveform shown in FIG. 2, the dissociation of the processing gas introduced into the processing container 2 is not excessively promoted. On the other hand, the phase of the high frequency wave of 380 kHz that accelerates the ions in the plasma and attracts them to the wafer W can be controlled by the phase controller 52. Therefore, FIG.
It is possible to attract the ions to the wafer W when the ion dissociation does not proceed excessively due to the high frequency. That is, when the most suitable ions for the predetermined etching are generated, it is possible to make them enter the wafer W. Therefore, it is possible to carry out etching with a high selection ratio.

The control of the high-frequency phase of 380 kHz that attracts the ions in the plasma to the wafer W is not limited to such a state in which dissociation does not proceed excessively. For example, dissociation proceeds to the final stage, and then again. The state of recombination to form radicals suitable for etching may be used as an index or a guide.

Furthermore, in actual processing, for example, a dummy wafer may be used to confirm the degree to which the phase of the high frequency wave of 380 kHz is shifted, and in that case, for example, processing gas, etching, base, etc. Depending on the type, the timing for shifting the phase of the high frequency of 380 kHz may be set in advance.

Next, another etching processing method using the above-described etching processing apparatus 1 will be described. In this example, the switches SW ₁ and SW ₂ are turned on, and the capacitance 56, and the capacitance 66 and the inductance 67.
Is connected to each of the corresponding power supply rods 55 and 56.
When applying high-frequency power to the susceptor 5 and the upper electrode 21, respectively, the phase controller 5 is connected to the susceptor 5.
A high frequency signal of 380 kHz from the oscillator 51 is passed through 2 and is directly amplified by the amplifier 53, and this is applied to the susceptor 5 through the matching device 54. On the other hand, the 13.56 MHz high frequency oscillated from the oscillator 61 also passes through the amplitude modulator 62, is amplified as it is, and is applied from the power feeding rod 65 to the upper electrode 21 via the matching device 64.

In this case, the matching unit 54 on the susceptor 5 side is
In the state of being matched to the high frequency of 380 kHz, the high frequency of 13.56 MHz incident from the upper electrode 21 becomes high impedance without any treatment and is incident from the upper electrode 21. Further, the high frequency becomes difficult to flow to the susceptor 5. Therefore, conventionally, this has caused the diffusion of plasma, resulting in a decrease in plasma density and non-uniformity of processing.

However, in this embodiment, the power feeding rod 55
Since the capacitance 56 is inserted between the upper electrode 21 and the ground,
A series resonant circuit can be formed. Therefore, by appropriately adjusting the value of the capacitance 56 in consideration of the distributed circuit constant, the combined impedance can be set to several Ω or less, and the high frequency wave from the upper electrode 21 can be obtained.
It is possible to increase the current density by facilitating the flow to the plasma, and to increase the density of generated plasma.

On the other hand, the power supply rod 65 on the upper electrode 21 side is also
Capacitance 66 and inductance 67 in series
380 has been inserted for the same reason as above.
The 380 kHz high frequency applied to the susceptor 5 side forms a series resonance circuit with respect to the high frequency of kHz, so that it easily flows into the upper electrode 21 and promotes the incidence of ions in the plasma on the wafer W. it can.

Therefore, it is possible to perform the etching of the highly fine processing on the wafer W under the high plasma density.
Further, as described above, since each high frequency wave between the upper electrode 21 and the susceptor 5 easily flows, it is possible to increase the plasma density without increasing the power so much,
The possibility of damaging the wafer W is lower than in the conventional case. Therefore, the yield is also improved.

In the above example, the upper electrode 21 has 1
A high frequency of 3.56 MHz and a high frequency of 380 kHz were applied to the susceptor 5, but it is not always necessary to stick to such frequencies, and the respective frequencies may be set according to the type of processing gas. In this case, in view of the followability of the ions in the plasma, a preferable result can be obtained by using the ion transition frequency peculiar to the introduced processing gas as a reference.

That is, a frequency lower than the lower ion transition frequency (LITF), for example, a high frequency power of 1 MHz or less is applied to the susceptor 5, and the upper electrode 21 is
A frequency higher than the upper ion transition frequency (UITF),
For example, high frequency power of 10 MHz or more may be applied. By doing so, the ions are efficiently accelerated with low power, and the followability of the ions in the sheath to the bias high frequency wave is stabilized even when the mixing ratio of the gas system or the degree of vacuum is slightly changed. Therefore, the ions can be made incident on the wafer W without being scattered in the sheath, so that fine processing can be performed at high speed. Further, since the ions can be made incident on the wafer W with stable incident energy, the conditions under which a stable process can be carried out are wider than before, and it is possible to realize process conditions that simultaneously satisfy the processing speed, the selection ratio, the shape, and the like. . Of course, since the power can be made smaller than in the conventional case, the damage of the wafer W is reduced and the yield is improved.

The gas to be introduced into the processing container 2 is, for example, a mixed gas of three kinds of gases A, B and C.
, The transition frequency regions Az, Bz,
When Cz is different, each transition frequency region A
z, Bz, Cz upper end ion transition frequencies Au, Bu,
A frequency higher than the highest frequency of Cu (Bu in the example of FIG. 4) is applied to the upper electrode 21, and each lower end ion transition frequency Al, B of each transition frequency region Az, Bz, Cz is applied.
A frequency lower than the lowest frequency of Cl and Cl (Cl in the example of FIG. 4) may be applied to the susceptor 5.

In each of the above-described embodiments, the object to be processed is a semiconductor wafer and the process is etching. However, the present invention is not limited to this and, for example, a process for processing an LCD substrate is performed. The present invention can be applied to not only etching but also sputtering and CVD processing.

[0049]

According to the first, second and third aspects of the present invention, the ion followability by the high frequency power applied to the first electrode is good, and the ions can be efficiently accelerated even with a small power. Moreover, since the plasma itself is stable,
Stable processing is possible even when the degree of vacuum or the gas mixing ratio changes.

According to claims 4, 5, and 6, the dissociation is prevented from proceeding excessively, and at the same time, the phase of generation of ions or radicals and acceleration of the ions to the object to be treated (applied to the first electrode side). By controlling the phase of electric power, it is possible to generate ions or radicals necessary for processing at a necessary timing and to make them enter the object to be processed. Therefore, plasma processing with good selectivity is possible. Also, damage to the object to be processed can be suppressed. Further, particularly according to claim 6, it is possible to perform control capable of appropriately coping with various processing situations.

According to the seventh and eighth aspects, the plasma density can be increased without increasing the power and frequency of the high frequency power, and the ion control can be made easier.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory diagram of an etching processing apparatus according to an embodiment of the present invention.

FIG. 2 is a graph showing a waveform of a high frequency applied to an upper electrode in an example.

FIG. 3 is a graph showing a waveform of a high frequency applied to a susceptor in an example.

FIG. 4 is an explanatory diagram showing the upper ion transition frequency and the lower ion transition frequency that should be adopted when using gases having different transition frequency regions.

[Explanation of symbols]

 1 Etching processing apparatus 2 Processing container 5 Susceptor 21 Upper electrode 51, 61 Oscillator 52 Phase controller 53, 63 Amplifier 54, 64 Matching device 56, 66 Capacitance 67 Inductance W Wafer

─────────────────────────────────────────────────── ───Continued from the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H01L 21/203 S 8719-4M 21/31

Claims (8)

[Claims] 1. Introducing a processing gas into the processing chamber,
High-frequency power is applied to the first electrode and the second electrode, which are provided to face each other in the processing chamber, to generate plasma, and the object in the processing chamber is treated under the plasma atmosphere. In the plasma processing method for performing a predetermined process according to 1., the frequency of the high frequency power applied to the first electrode is lower than the frequency of the high frequency power applied to the second electrode. A high frequency power having a frequency lower than an ion transition frequency is applied to the first electrode, and a high frequency power having a frequency higher than an upper end ion transition frequency specific to the processing gas is applied to the second electrode. , Plasma treatment method. 2. A process gas in which a plurality of gases are mixed is introduced into the process chamber, and high-frequency power is applied to the first electrode and the second electrode facing each other in the process chamber. In the plasma processing method of generating plasma and subjecting the object to be processed in the processing chamber to a predetermined process under the plasma atmosphere, the frequency of the high frequency power applied to the first electrode is the second frequency. The frequency of the high frequency power applied to the electrode is lower than the frequency of the high frequency power applied to the electrode, and the low frequency high frequency power of each unique lower ion transition frequency of each individual gas in the processing gas is applied to the first electrode. Applying the high frequency power of the highest frequency among the individual upper end ion transition frequencies for each individual gas in the process gas to the second electrode. Zuma processing method. 3. A process gas in which a plurality of gases are mixed is introduced into the process chamber, and high-frequency power is applied to the first electrode and the second electrode, which are provided to face each other in the process chamber. In a plasma processing method of generating plasma and subjecting an object in the processing chamber to a predetermined process under the plasma atmosphere, the frequency of the high-frequency power applied to the first electrode is 1 MHz.
z or less, the frequency of the high frequency electric power applied to the said 2nd electrode is 10 MHz or more, The plasma processing method characterized by the above-mentioned. 4. Introducing a processing gas into the processing chamber,
High-frequency power is applied to the first electrode and the second electrode, which are provided to face each other in the processing chamber, to generate plasma, and the object in the processing chamber is treated under the plasma atmosphere. In the plasma processing method, the high frequency of a frequency higher than the high frequency applied to the first electrode is applied to the second electrode at the same frequency as the high frequency applied to the first electrode. A plasma processing method, characterized in that amplitude-modulated power is applied. 5. A process gas is introduced into the process chamber, and
High-frequency power is applied to the first electrode and the second electrode, which are provided to face each other in the processing chamber, to generate plasma, and the object in the processing chamber is treated under the plasma atmosphere. In the plasma processing method of performing a predetermined process according to 1., high frequency power having a frequency of 100 kHz to 1 MHz is applied to the second electrode and 10 is applied to the first electrode.
A plasma processing method, characterized in that an electric power obtained by amplitude-modulating a frequency of MHz or more at the same frequency as a high frequency applied to the first electrode is applied. 6. The plasma processing method according to claim 4, wherein the amplitude modulation is performed by any one of a sine wave, a triangular wave, a rectangular wave, a sawtooth wave, or a composite waveform thereof. 7. A first electrode having a first electrode and a second electrode facing each other in a processing chamber, and the first electrode on which a target object is placed is connected to a relative low frequency power source through a matching circuit. In the plasma processing apparatus, the second electrode is connected to a high frequency power source via a matching circuit, a capacitance component is inserted between the first electrode and the matching circuit and the ground, and A plasma processing apparatus, wherein a capacitive component and an inductive component are inserted in series between the electrode and the matching circuit thereof and the ground. 8. A first electrode having a first electrode and a second electrode facing each other in a processing chamber, and the first electrode on which the object to be processed is mounted is connected to a relative low frequency power source through a matching circuit. In the plasma processing apparatus, the second electrode is connected to a high frequency power source through a matching circuit, and a combined impedance for high frequency power is several Ω or less between the first electrode and the matching circuit and the ground. , And an impedance component is inserted so that the impedance for low-frequency power becomes several kΩ or more, and the combined impedance for high-frequency power is several kΩ between the second electrode and its matching circuit and the ground.
The plasma processing apparatus is characterized in that an impedance component including a capacitance component is inserted in series so that the impedance with respect to low-frequency power is several Ω or more.