JP2003077699A - Plasma treatment method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma treatment method and apparatus that can irradiate sufficient-energy ions to a wafer under treatment. SOLUTION: A plasma treatment apparatus is equipped with an introducing portion for introducing plasma-generating gas into a plasma treatment chamber, a first applying portion for applying first high-frequency power to the plasma- generating gas introduced from the introducing portion, and a second applying portion for applying second high-frequency power generated at a higher oscillation frequency than 13.56 MHz to a water under treatment mounted in the plasma treatment chamber, a pressure controller. The controller connects a high-frequency oscillator for generating the second high-frequency power to the wafer under treatment through a connecting portion having a capacitive component which is not less than the capacitie component of a sheath region generated by the generation of the plasma so that the pressure in the plasma treatment chamber is controlled to a pressure causing no impingement of the ions in the plasma against one another in the sheath region.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process of efficiently injecting ions having uniform energy in high-density plasma generated by surface wave plasma into a substrate such as film formation, etching, cleaning, and surface modification. The present invention relates to a plasma processing method and apparatus to be performed.

[0002]

2. Description of the Related Art Conventionally, as a plasma processing apparatus using microwaves as an excitation source for generating plasma, an ultra-precision dry etching apparatus, an ultra-thin film forming apparatus, a low damage cleaning apparatus, a CVD apparatus, an etching apparatus, an ashing apparatus, etc. It has been known.

CVD using a so-called microwave plasma chemical vapor deposition (CVD) apparatus is performed, for example, as follows. That is,
A gas was introduced into the plasma generation chamber and the film formation chamber of the microwave plasma CVD apparatus, and at the same time, microwave energy was input to generate plasma in the plasma generation chamber to excite and decompose the gas, and the gas was placed in the film formation chamber. A deposited film is formed on the substrate to be processed.

Further, the etching process of the substrate to be processed using a so-called microwave plasma etching apparatus is performed as follows, for example. That is, an etchant gas is introduced into the processing chamber of the apparatus, and at the same time, microwave energy is input to excite and decompose the etchant gas to generate plasma in the processing chamber. The surface of the treated substrate is etched.

Further, the ashing process of the substrate to be processed using a so-called microwave plasma ashing device is
For example, it is performed as follows. That is, an ashing gas is introduced into the processing chamber of the apparatus, and at the same time, microwave energy is input to excite and decompose the ashing gas to generate plasma in the processing chamber, whereby the target placed in the processing chamber is discharged. The surface of the treated substrate is ashed.

By the way, in many cases, ions in the plasma are made incident on the substrate to be processed at a frequency of 100 kHz to 13.56 MHz oscillated by a high-frequency oscillator or the like. For example, in Japanese Patent No. 3067289, this frequency is 13 A technique for narrowing the distribution width of the ion energy of the ions incident on the substrate to be processed by setting the frequency to 0.56 MHz or higher is described.

When the ion energy has a distribution width, the substrate to be processed is damaged by the incidence of high-energy ions, and the angle at which low-energy ions are laterally disturbed by thermal vibration in plasma is large. This is because the light may not be incident on the substrate to be processed at a required angle and the reaction on the surface of the substrate to be processed may not be uniform, resulting in the following problems.

When the plasma processing apparatus is used as a dry etching apparatus, bowing, in which the etching cross-sectional shape of the hole is barrel-shaped, is formed in the substrate to be processed by obliquely incident ions, micro-trench in which the etching bottom surface is an inverted M-shape, etc. Abnormal shape occurs.

The bowing shape is generated by the obliquely incident ions colliding with the pattern side wall and etching the side wall. Further, the micro-trench is generated when a part of the obliquely incident ions is reflected by the side wall and the amount of ion incident near the side wall of the pattern bottom surface increases.

Further, when the plasma processing apparatus is used as a film forming apparatus, not only the reaction probability on the surface of the substrate to be processed but also the reaction form varies. Therefore, for example, the decomposition of the mother gas is insufficient, which causes deterioration of the film quality such as carbon residue and nonuniformity.

Further, when the plasma processing apparatus is used as an ion implantation apparatus, the distribution of ion energy directly corresponds to the implantation depth distribution, so that the distribution width is preferably narrow.

Incidentally, the incident angle distribution θ of the ions
_{The IAD,} the ion temperature in the plasma T _i, the sheath voltage V
_sh, the ion energy equivalent amount incident on the target substrate and eV _sh, can be represented by formula as _{θ IAD = arctan (kT i /} eV sh) 1/2.

[0013]

However, the patent No. 306 is used.
The method described in No. 7289 has the following problems. That is, the energy of the ions incident on the substrate to be processed can be limited to about 100 eV at the maximum.

With this level of energy, for example, it may take a long time for etching, or it may not be possible to etch into a desired shape, and there are many things that cannot be etched in the first place.

Therefore, an object of the present invention is to allow ions of sufficient energy to enter the substrate to be processed.

[0016]

In order to solve the above problems, the present invention relates to an introduction part for introducing a plasma generation gas into a plasma processing container, and a plasma generation gas introduced by the introduction part. A first applying part for applying one high frequency power, and a second applying part for applying a second high frequency power generated at an oscillation frequency higher than 13.56 MHz to the substrate to be processed placed in the plasma processing container. In a plasma processing apparatus including: a high-frequency oscillator for generating the second high-frequency power, and the substrate to be processed, connection of a capacitive component equal to or greater than a capacitive component of a sheath region generated by generating the plasma. And a pressure control unit for controlling the pressure in the plasma processing container so that the ions in the plasma do not collide with each other in the sheath region.

Further, according to the present invention, a plasma generating gas is introduced into the plasma processing container, a first high frequency power is applied to the plasma generating gas, and the substrate to be processed is placed in the plasma processing container. In a plasma processing method of applying a second high frequency power generated at an oscillation frequency higher than 13.56 MHz, the high frequency oscillator for generating the second high frequency power and the substrate to be processed generate the plasma. It is characterized in that the connection is made at a connection portion of a capacity component equal to or greater than the capacity component of the sheath region generated by the above, and the pressure in the plasma processing container is set to a pressure at which ions in the plasma do not collide with each other in the sheath region. And

The plasma processing container is provided with a dielectric window, and the first high frequency power is plasma-processed through the dielectric window by a flat slot antenna such as an endless annular waveguide with a slot. It is put in a container to generate plasma such as surface wave interference plasma. The oscillation frequency is higher than the reciprocal of the time taken for ions in the plasma to pass through the sheath region and lower than the electron plasma frequency.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(Description of Configuration) FIG. 1 is a sectional view showing a schematic configuration of a plasma processing apparatus according to an embodiment of the present invention. In FIG. 1, 101 is a high frequency oscillator for generating and maintaining plasma, 102 is a waveguide for guiding the high frequency from the high frequency oscillator 101, 103 is a matching device for matching the high frequency guided by the waveguide 102, and 107 is A vacuum container which is a plasma processing container, 104 is an annular waveguide for introducing high frequency waves into the vacuum container 107 through the dielectric window 106, and 105 is for introducing high frequency waves into the vacuum container 107 together with the annular waveguide 104. Slot antenna, 10
Reference numeral 6 is a dielectric window that transmits high-frequency power and isolates the inside and outside of the vacuum container 107, 108 is a gas inlet for introducing gas into the vacuum container 107, 109 is an exhaust port for exhausting the inside of the vacuum container 107, and 114 is a substrate to be processed. Where 110 is a silicon (Si) wafer, and 110 is a silicon wafer 11 in which ions in the plasma generated by the high frequency oscillator 101
4 is a high-frequency oscillator that oscillates a frequency of several hundred MHz or more in order to pull in 4, 111 is a silicon wafer 114
DC power source for applying C component, 112 is high frequency oscillator 10
A blocking capacitor having a capacitance based on the voltage applied to the matching circuit connected to 0 or the size of the circuit element in the matching circuit, and 113 is a low-pass for preventing the power from the high-frequency oscillator 110 from being related to the DC power supply 111 side. A filter 115 is an electrostatic chuck that electrostatically adsorbs the silicon wafer 114, and 116 and 117 are a susceptor cover and a vacuum container wall cover that prevent metal components such as the vacuum container 107 from entering the silicon wafer 114.

Although the silicon wafer 102 will be described as an example of the substrate to be processed, it is not essential that the substrate to be processed is a semiconductor substrate, and Fe, Ni, Cr, A may be used.
Metals such as 1, Mo, Au, Nb, Ta, V, Ti, Pt, and Pb or alloys thereof, such as a conductive base made of brass, stainless steel, or the like, SiO ₂ -based quartz or various glasses, Si ₃ N ₄ , NaCl, KCl, LiF, C
_{aF2, BaF 2, Al 2 O} 3, AlN, inorganic substances such as MgO, polyethylene, polyester, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, organic substances such as polyimide films, sheets, etc. An insulating base material can be used.

Further, as the high frequency oscillator 101, a microwave power source, a VHF power source, an RF power source or the like can be used. In this case, a rod-shaped antenna, a coil, an electrode for inductive coupling, an electrode for capacitive coupling, or the like can be used to supply electric power into the container to generate plasma.

(Explanation of Operation) First, the vacuum container 1 is operated by a vacuum pump (not shown) connected to the exhaust port 109.
The inside of 07 is evacuated to a high vacuum of about 1 × 10 ⁻³ Pa, and the silicon wafer 114 is placed on a monopolar electrostatic chuck 115 from a load lock chamber (not shown).

After that, for example, a negative DC voltage is applied to the electrostatic chuck 115. Next, gas is introduced into the vacuum container 107, and a variable conductance valve (not shown) is adjusted to maintain the pressure inside the vacuum container 107 at a predetermined value.

Next, a high frequency wave of, for example, 2.45 GHz is radiated from the high frequency oscillator 101 into the vacuum container 107 through the slot antenna 105 to generate surface wave interference plasma (SIP).

This surface wave interference plasma has an electron density Ne.
= 1 x 10¹²~ 1 x 10¹³/ Cm³The ultra high density
It is a plasma and is generated on the surface of the dielectric window 106. Invitation
Silicon placed about 150 mm below the electrical window 106
For the wafer 114 as well, the pressure inside the vacuum container 107 is set to 3 Pa.
Electron density Ne = 1 × 10¹¹~ 1 x 10 ¹²
/ Cm³High electron density. Also, the low electron temperature T
e is about 2 eV.

Further, when the pressure in the vacuum container 107 is set to 3 Pa and argon gas is introduced from the gas inlet 108, the ion energy of the ions colliding with the inner wall of the vacuum container 107 is about 10 eV, and the ion energy distribution (half) The value width) is 2 eV, and the ion energy distribution of the ions incident on the silicon wafer 114 becomes narrow.

Next, about 1 second after the plasma is generated, cooling He is introduced into the back surface of the silicon wafer 114 from a gas inlet (not shown). Then, the high frequency oscillator 110 is used for the silicon wafer 114 for several 100M.
When a high frequency of Hz is applied, ions in the plasma are accelerated by the DC component V _DC of the potential difference between the plasma and the silicon wafer 114 and are incident on the silicon wafer 114.

By changing the gas introduced into the vacuum container 107,
By properly selecting the incident ions, processes such as etching, cleaning, ashing, film formation, surface modification, and impurity implantation can be performed.

The frequency of the high frequency oscillator 110 is several 100M.
By using a high frequency of Hz, the silicon wafer 1 can be used without spreading the ion energy distribution of the vacuum container 107.
Ions can be made incident on 14.

In the high density plasma, in order to efficiently apply the DC component V _DC of the potential difference between the plasma and the silicon wafer 114 to the ions in the plasma, the capacitance between the high frequency oscillator 110 and the silicon wafer 114 is required. It is necessary to increase the composition.

FIG. 2 is an equivalent circuit diagram showing the capacitance and the like between the high frequency oscillator 110 and the silicon wafer 114 of FIG. The capacity includes the capacity of the sheath region (anode sheath capacity, cathode sheath capacity), the capacity of the He layer on the back surface of the silicon wafer 114 introduced for cooling, the electrostatic chuck 11.
There is a capacity of 5 and a capacity of the blocking capacitor 112.

In the high-density plasma, the impedance of the sheath region must be sufficiently higher than the other impedances in order to generate the DC component V _DC of the potential difference between the plasma and the silicon wafer 114, in other words, the other capacitances. It should be sufficiently larger than the volume of the sheath area.

Therefore, the blocking capacitor 112,
The capacitance of the He layer and the electrostatic chuck 115 is increased. Specifically, the He layer is thinned by about 30 μm, and the dielectric layer of the electrostatic chuck 115 is also thinned by about 0.3 mm.
The material is aluminum nitride.

Further, the capacitance of the blocking capacitor 112 is set to 10,000 pF.

By using the apparatus configuration and the processing conditions as described above, it is possible to control the energy of ions having uniform energy with a sufficiently high flux to control the silicon wafer 1.
14 can be made incident.

A method of narrowing the ion energy distribution of the ions incident on the silicon wafer 114 will be described below.

First, there are the following three main factors causing the ion energy distribution. That is, the energy distribution of the ions in the vacuum container 107, the temporal variation of the voltage of the sheath region that draws the ions into the silicon wafer 114, and the scattering of the ions in the sheath region are the factors.

The ion energy distribution in the vacuum chamber 107 depends on the frequency of the high frequency for maintaining the plasma and the density of the generated plasma. That is, when plasma is generated at a low frequency, the ions in the plasma follow the high frequency, and the vibration of the sheath region due to the high frequency accelerates the ions in the plasma, resulting in a wide ion energy distribution width.

On the other hand, when the plasma is generated at a high frequency, the ions in the plasma cannot follow and the plasma is maintained mainly only by electron acceleration, and as a result, the ion energy distribution may be narrowed.

FIG. 3 shows the plasma excitation frequency (Freq)
It is a figure which shows the measurement result of the ion energy distribution in the vacuum container 107 in case of 13.56 MHz and 2.45 GHz.

When the plasma excitation frequency is 2.45 GHz, the ion energy distribution width (half-value width) is about 2 eV, which is a single ion energy. On the other hand, when the plasma excitation frequency is 13.56 MHz, which is widely used in CCP and ICP, the ion energy distribution width (half-value width) is not only widened by about 1 eV, but also low energy A sub-peak is also seen on the side, and it is difficult to say that it is a single ion energy anymore.

The influence of the time variation of the voltage in the sheath region for drawing the ions into the silicon wafer 114 is also affected by the vacuum container 107.
As in the above case, it depends on the frequency of the high frequency and the density of the generated plasma.

The relationship between the frequency of the high frequency applied to the silicon wafer 114 and the energy distribution width of the incident ions is investigated by, for example, Panagopoulos et al., And its details are described in Journal of Applied Physics Vol.85 No.7 (1999) pp. .
3435.

When the high frequency voltage applied to the silicon wafer 114 is V (t) = V _DC + V _AC sin (ωt), the incident ion energy distribution width ΔE _i is the ion transit time τ _i in the sheath region. the sheath region thickness d, the voltage of the sheath region V _sh, the mass of the ions when the m _i in the low frequency _{side, ΔE i ~2V AC: ωτ I} «1 Further, in the high frequency side, Delta] E _i ~ 2V _AC / ωτ _i : ωτ _I ≧ 1.

Here, the transit time τ _i of the ions in the sheath region can be expressed as follows.

Τ _i = 3d√ (m _i / 2eV _sh ) The sheath region thickness d can be expressed as follows.

D = √ (λ _d ² (eV _sh /kTe-0.5)
^3/2/0/97 ) These results show that on the low frequency side, the ion incident energy distribution width [eV] is “e · amplitude of applied high frequency (Vp
p) ”[eV], which indicates that the distribution width narrows at a ratio of 1 / ωτ _{i as} the frequency increases on the high frequency side.

FIGS. 4 (a) and 4 (b) show Ar ions with a mass number of 40, which are widely used in plasma processes.
= 1 × 10 ¹¹ cm ^-3 , 5 × 10 ¹¹ cm ^-3 , 1 × 10 ¹² c
It is a figure based on the calculation result of (DELTA) Ei in the case of the plasma of m < ^-3 >, Te = 2eV. Incidentally, V _AC in FIG. 4 (a)
= 100V, and FIG. 4B shows the results when V _AC = 200V.

Where V_AC= V_shAnd Incident ion
To reduce the energy distribution to, for example, 10% or less, V_AC
Regardless of whether the voltage is 100 V or 200 V, Ne = 1 ×
10 ¹¹cm^-3200MHz or more, 5 × 10¹¹cm^-3
400MHz or more, 1 × 10¹²cm^-3At the time of 500
Bias frequency (Freque) above (5.E + 08) MHz
ncy) is required.

In the case of NH ₃ having a mass number of 17,
τ _i is 2/3, and the ion energy distribution width is about 2 /
3 times.

The ion incident angle distribution is θ _IAD = arct
It is given by an (kT _i / eV _sh ) 1/2. When the incident ion energy eV _sh fluctuates by 10%, the spread of the angular distribution is as slight as 0.2 ° at V _AC = 100V and 0.15 ° at V _AC = 200V.

As calculated above, the ion energy distribution largely depends on the plasma density, the electron temperature, the mass of incident ions, and the like. The above calculation was performed for high density plasma, but the required frequency also changes significantly when the plasma conditions change.

Ion scattering in the sheath region can be roughly evaluated by the sheath region thickness and the mean free path of gas. That is, when the ions in the plasma do not collide with each other in the sheath region (mean free path), they can be considered to be incident on the silicon wafer 114 without losing energy.

The mean free path is represented by 1 / (√2πna ² ) where n is the number of particles in a unit volume and a is a particle radius when approximated by a hard sphere model.

Here, with Ar ions having a mass number of 40, Ne
Considering the case of plasma of = 1 × 10 ¹¹ cm ⁻³ and Te = 2 eV, the pressure at which ions in the plasma do not collide in the sheath region is 1 Pa, V when V _sh is 100 V.
_{When sh} is 500V, it becomes about 0.3Pa.

If the density of the plasma is further increased, the thickness of the sheath region is reduced, so that it is possible to realize a sheath region free from ion collision even at a higher pressure.

Although a part thereof will be described in the following embodiment, various gases are selectively introduced from the gas inlet 108 to obtain Si ₃ N ₄ , SiO ₂ , SiOF, Ta ₂ O ₅ and Ti.
It is also possible to deposit an insulating film of O ₂ , TiN, Al ₂ O ₃ , AlN, MgF _2, or the like.

At this time, the gas introduced is SiH._Four, Si₂
H₆Inorganic silanes such as tetraethoxysilane (TE
OS), tetramethoxysilane (TMOS), octame
Tylcyclotetrasilane (OMCTS), dimethyldiph
Luorosilane (DMDFS), dimethyldichlorosilane
Organosilanes such as (DMDCS), SiF4, Si ₂
F₆, Si₃F₈, SiHF₃, SiH₂F₂, SiCl_Four，
Si₂Cl₆, SiHCl ₃, SiH₂Cl₂, SiH₃C
l, SiCl₂F₂Such as halogenated silanes at room temperature
Those that are in a gas state under pressure or that can be easily gasified
Can be mentioned.

In this case, the nitrogen raw materials introduced at the same time
As the gas or oxygen source gas, N ₂, NH₃, N₂H_Four,
Hexamethyldisilazane (HMDS), O₂, O₃, H₂
O, NO, N₂O, NO₂And so on.

In addition, a-Si, poly-Si, Si
It is also possible to deposit a semiconductor film such as C or GaAs.
At this time, the gas to be introduced is SiH_Four, Si₂H₆Nothing
Silanes, Tetraethylsilane (TES), Tetrame
Tyrsilane (TMS), dimethylsilane (DMS), disilane
Methyldifluorosilane (DMDFS), Dimethyldisilane
Organic silanes such as Lolsilane (DMDCS), SiF
_Four, Si₂F₆, Si₃F₈, SiHF₃, SiH₂F₂, Si
Cl_Four, Si₂Cl₆, SiHCl₃, SiH₂Cl ₂, Si
H₃Cl, SiCl₂F₂Halogenated silanes such as
Those that are in a gas state at normal temperature and pressure or can be easily gasified
There are things.

In this case, the additive gas or carrier gas which may be mixed with the Si source gas and introduced is H ₂ , H
Examples thereof include e, Ne, Ar, Kr, Xe and Rn.

Further, a metal film of Al, W, Mo, Ti, Ta or the like can be deposited. At this time, the gas introduced is trimethylaluminum (TMAl), triethylaluminum (TEAl), triisobutylaluminum (TIBAl), dimethylaluminum hydride (DMAlH), tungsten carbonyl (W (C
O) ₆ ), molybdenum carbonyl (Mo (CO) ₆ ), organic metals such as trimethylgallium (TMGa) and triethylgallium (TEGa), AlCl ₃ , WF ₆ , Ti
Examples thereof include halogenated metals such as Cl ₃ and TaCl ₅ .

In this case, the additive gas or carrier gas which may be mixed with the Si source gas and introduced is H
₂ , He, Ne, Ar, Kr, Xe, and Rn.

Furthermore, Al ₂ O ₃ , AlN, Ta
It is also possible to form a metal compound thin film of ₂ O ₅ , TiO ₂ , TiN, WO _3, or the like. At this time, the introduced gas is trimethylaluminum (TMAl), triethylaluminum (TEAl), triisobutylaluminum (TI).
BAl), dimethyl aluminum hydride (DMA)
1H), tungsten carbonyl (W (CO) ₆ ), molybdenum carbonyl (Mo (CO) ₆ ), trimethylgallium (TMGa), triethylgallium (TEGa)
Organic metal such as AlCl ₃ , WF ₆ , TiCl ₃ , Ta
Examples thereof include halogenated metals such as Cl ₅ .

In this case, the oxygen raw material introduced at the same time
As the gas or the nitrogen source gas, O ₂, O₃, H₂O, N
O, N₂O, NO₂, N₂, NH₃, N₂H_Four, Hexamethyl
Disilazane (HMDS) etc. are mentioned.

[0067]

EXAMPLES Some examples of the present invention will be described below.

Example 1 In Example 1 of the present invention, Ar was used.
Discharge was performed using gas, and the ion energy incident on the biased electrode was analyzed.

FIG. 5 is a sectional view showing a schematic structure of the plasma processing apparatus according to the first embodiment of the present invention. This device
In addition to the plasma processing apparatus shown in FIG.
18 and a mass spectrometer 719 with an ion energy analyzer
It is equipped with and.

First, a turbo molecular pump was attached to the apparatus shown in FIG. 5, and the inside of the vacuum container 107 was evacuated to a pressure of 1 × 10 ⁻³ Pa. Next, plasma was generated under the following conditions.

Gas type: Ar Flow rate: 200 sccm Pressure: 1 Pa Oscillation frequency of high frequency oscillator 101, power: 2.45 G
Hz, 2 kW High-frequency oscillator 110 oscillation frequency, power: 200 MH
z, 300W electrostatic attraction voltage: -200V

Next, the incident energy distribution of Ar ⁺ ions having a mass number of 40 was measured by a mass spectrometer equipped with an ion energy analyzer. As a result, the average ion incident energy was 121 eV and the energy distribution width (half-value width) was 6.
It was 8 eV.

(Embodiment 2) In Embodiment 2 of the present invention, FIG.
The Cl ₂ gas was introduced into the apparatus described above to etch the poly-Si film.

First, an oxide film of about 5 nm is formed by RTP on a 9-inch silicon wafer 114, and an oxide film of 10 nm is formed thereon.
A 0 nm poly-Si film is formed by LPCVD, and Kr
A 0.2 μm line and space pattern was patterned with a photoresist using an F excimer stepper. This wafer is placed on a placing table and a vacuum container 1 is used until the pressure reaches 1 × 10 ⁻³ Pa using a turbo molecular pump.
The inside of 07 was evacuated.

Next, plasma was generated under the following conditions to etch the poly-Si film.

[First Step] Gas type: Cl ₂ Flow rate: 200 sccm Pressure: 0.5 Pa Silicon wafer 114 temperature: 20 ° C. Power of high frequency oscillator 101: 2 kW Frequency of high frequency oscillator 110, power: 200 MHz,
600W Electrostatic attraction voltage: -200V Etching time: 10 seconds

[Second Step] Gas species: Cl ₂ Flow rate: 200 sccm Pressure: 1 Pa Silicon wafer 114 temperature: 20 ° C. Power of high frequency oscillator 101: 2 kW Frequency of high frequency oscillator 110, power: 200 MHz,
300W Electrostatic attraction voltage: -200V Etching time: 40 seconds

The plasma density and electron temperature at the position of the silicon wafer 114 in the first step are "Ne = 1.
It was 5 * 10 < ¹¹ > / cm < ³ >"and" Te = 2.3eV. " The plasma density and electron temperature at the position of the silicon wafer 114 in the second step are “Ne = 3.2”, respectively.
× 10 ¹¹ / cm ³ ”,“ Te = 2.0 eV ”.

Further, V _DC in the first and second steps were 185 V and 85 V, respectively.

Poly measured on the test wafer in advance
The etching rates of the -Si film and the oxide film are 85 nm / min for the poly-Si film, 5 nm / min for the oxide film, 132 nm / min for the poly-Si film and 0 nm for the second step, respectively. It was 0.4 nm / min.

When the wafer etched under the above conditions was observed with a scanning electron microscope (SEM), the cross-sectional shape of the etched portion was vertical, and abnormalities such as undercuts and abrasion of the underlying gate oxide film were also observed. There wasn't. In addition, a transistor was manufactured using the silicon wafer 114 processed under the same conditions and its characteristics were evaluated.
No abnormalities such as deterioration of withstand voltage of the gate oxide film and fluctuation of threshold value were observed.

Example 3 In Example 3 of the present invention, FIG.
Introduce a mixed gas of NH ₃ and Ar into
The ow-k film was etched.

First, a 100 nm oxide film is formed by plasma CVD on an 8-inch silicon wafer 114, a 400 nm polyaryl ether (PAE) film is applied thereon, and a 100 nm oxide film for a hard mask is further formed. It was formed by plasma CVD and a hole pattern of 0.15 μm to 0.5 μm was patterned with a photoresist using a KrF excimer stepper.

This wafer was first subjected to a commercially available parallel plate type RI.
It was inserted into the E apparatus, and the hard mask was etched with plasma of C ₄ F ₈ / CO / Ar gas.

Next, this wafer is placed on the placing table and
1 x 10 using a robot molecular pump ^-3Pa pressure
The inside of the vacuum container 107 was evacuated.

Next, plasma was generated under the following conditions to etch the poly-Si film.

Gas type: NH ₃ / Ar Flow rate: 50/200 sccm Pressure: 1 Pa Silicon wafer 114 temperature: -20 ° C. Power of high frequency oscillator 101: 1.8 kW Frequency of high frequency oscillator 110, power: 200 MHz,
300W Electrostatic attraction voltage: -200V Etching time: 140 seconds

The plasma density and the electron temperature at the position of the silicon wafer 114 are "Ne = 3.0 × 10 ¹¹ / c", respectively.
m ³ ”and“ Te = 2.0 eV ”. Further, V _DC was 93V.

The etching rate of the PAE film measured on the test wafer in advance was 238 nm / min.

When the wafer etched under the above conditions was observed with a scanning electron microscope (SEM), the sidewalls of the holes were vertical and no abnormal shape such as undercut or bowing was observed. In addition, a wiring evaluation TEG was produced using the silicon wafer 114 processed under the same conditions, and its electrical characteristics were evaluated. No abnormality such as disconnection or increase in via resistance value was observed in the 100,000-step via chain. It was

Example 4 In Example 4 of the present invention, FIG.
Introduce a mixed gas of NH ₃ and Ar into
The ow-k film was etched.

First, a 100 nm oxide film is formed on an 8-inch silicon wafer 114 by plasma CVD, a 400 nm polyarylether (PAE) film is applied thereon, and a 100 nm oxide film for a hard mask is further formed. It was formed by plasma CVD, and a 0.2-1.0 μm line and space pattern was patterned with a photoresist using a KrF excimer stepper.

This wafer is first processed into a commercially available parallel plate type RI.
It was inserted into the E apparatus, and the hard mask was etched with plasma of C ₄ F ₈ / CO / Ar gas.

Next, this wafer is placed on a mounting table and
1 x 10 using a robot molecular pump ^-3Pa pressure
The inside of the vacuum container 107 was evacuated.

Next, plasma was generated under the following conditions to etch the poly-Si film.

Gas type: NH ₃ / Ar Flow rate: 50/200 sccm Pressure: 1 Pa Silicon wafer 114 temperature: -20 ° C. Power of high frequency oscillator 101: 1.8 kW Frequency of high frequency oscillator 110, power: 200 MHz,
300W Electrostatic attraction voltage: -200V Etching time: 50 seconds

The plasma density and electron temperature at the position of the silicon wafer 114 are respectively "Ne = 3.0 × 10 ¹¹ / c".
m ³ ”and“ Te = 2.0 eV ”. Further, V _DC was 93V.

The etching rate of the PAE film measured on the test wafer in advance was 238 nm / min.

When the wafer etched under the above conditions was observed with a scanning electron microscope (SEM), it was found that
The etching depth of the 2 μm wide groove was about 207 nm. Further, the side walls of the groove were vertical and there was no damage to the hard mask, and the surface roughness of the micro trench and the groove bottom was not observed.

Further, the etching depth of the groove having a width of 0.2 μm to 1.0 μm was within the range of 205 ± 5 nm. Next, a wiring evaluation TEG was produced using the silicon wafer 114 processed under the same conditions, and its electrical characteristics were evaluated. The in-plane distribution of the sheet resistance of the damascene wiring was about 9.5% at 3σ. .

Example 5 In Example 5 of the present invention, FIG.
O ₂ , CF ₄ and H ₂ gas were used in the above apparatus to remove the polymer after etching the oxide film.

First, a 600 nm oxide film is formed on an 8-inch silicon silicon wafer 114 by plasma CVD, and 0.2 to 1.0 is formed by using a KrF excimer stepper.
A hole pattern of μm was patterned with a photoresist.

This wafer was first subjected to a commercially available parallel plate type RI.
It was inserted into the E apparatus, and the oxide film was etched by plasma of C ₄ F ₈ / CO / Ar gas.

Next, ashing of the photoresist was performed using a commercially available photoresist ashing device.
The polymer that could not be removed only by ashing remained on the wafer surface and the side walls of the holes.

Next, this wafer is placed on the placing table and
1 x 10 using a robot molecular pump ^-3Pa pressure
The inside of the vacuum container was evacuated to.

Next, plasma is generated under the following conditions,
The polymer was removed.

Gas type: O ₂ / CF ₄ / H ₂ Flow rate: 200/3/5 sccm Pressure: 1 Pa Silicon wafer 114 temperature: 50 ° C. High frequency oscillator 101 power: 2.5 kW High frequency oscillator 110 frequency, power: 200 MHz,
150W Electrostatic attraction voltage: -200V Processing time: 60 seconds

The plasma density and electron temperature at the position of the silicon wafer 114 are respectively “Ne = 2.2 × 10 ¹¹ / c”.
m ³ ”and“ Te = 1.9 eV ”. Further, V _DC was 56V.

When the surface of the wafer treated under the above conditions was observed with a scanning electron microscope (SEM), the polymer in the hole and on the surface of the wafer was removed.

[0110]

As described above, according to the present invention,
Ion energy of at least 100 eV or more can be incident on the substrate to be processed.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic configuration of a plasma processing apparatus according to an embodiment of the present invention.

FIG. 2 is a high-frequency oscillator 110 and a silicon wafer 1 of FIG.
It is an equivalent circuit diagram which shows the capacity | capacitance between 14 and the like.

FIG. 3 shows a plasma excitation frequency of 13.56 MHz and 2.
It is a figure which shows the measurement result of the ion energy distribution in the vacuum container 107 in the case of 45 GHz.

FIG. 4 is a mass number 40 widely used in plasma processes.
With Ar ions of Ne = 1 × 10 ¹¹ cm ⁻³ , 5 × 10 ¹¹
cm ^-3, a diagram based on ^{1 × 10 12 cm -3, Te} = 2eV case of the plasma for the ΔEi calculation result of.

FIG. 5 is a cross-sectional view showing a schematic configuration of the plasma processing apparatus according to the first embodiment of the present invention.

[Explanation of symbols]

101,110 High frequency oscillator 102 Waveguide 103 Matching device 104 annular waveguide 105 slot antenna 106 Dielectric window 107 vacuum container 108 gas inlet 109 exhaust port 111 DC power supply 112 blocking capacitors 113 Low-pass filter 114 substrate to be treated 115 Electrostatic chuck 116 susceptor cover 117 Vacuum container wall cover 718 Orifice 719 Mass spectrometer with energy analyzer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 21/205 H01L 21/205 5F033 21/285 21/285 C 5F045 21/3065 21/31 C 21/31 21/302 B 21/768 21/90 K F term (reference) 4G075 AA24 AA30 AA61 AA62 BC04 BC06 BC08 BD14 CA25 CA47 EB24 EB42 4K030 AA06 AA09 AA14 AA18 BA29 BA30 BA40 CA04 FA01 DB03 DB03 DB06 DB06 DB02 DB03 DB02 DB03 DB02 DB03 DD03 DD07 DD08 DG08 DG13 DG15 DK03 DM05 DM18 DM28 DM29 DM32. PP12 RR03 RR04 RR05 RR06 RR11 SS01 SS02 SS03 SS04 SS15 WW00 5F045 AA08 AB03 AB04 AB06 AB10 AB31 AB32 AB33 AC01 AC03 AC05 AC08 AC12 AC16 DP03 EH11 EH20 EJ 10 EM05 GB08

Claims (6)

[Claims] 1. An introduction part for introducing a plasma generation gas into a plasma processing container, a first application part for applying a first high-frequency power to the plasma generation gas introduced by the introduction part, and the plasma treatment. A plasma processing apparatus, comprising: a second application unit for applying a second high frequency power generated at an oscillation frequency higher than 13.56 MHz to a substrate to be processed placed in a container, wherein the second high frequency power is generated. The high-frequency oscillator and the substrate to be processed are connected at a connecting portion of a capacitive component equal to or greater than the capacitive component of the sheath region generated by generating the plasma, and the pressure in the plasma processing container is controlled in the plasma. A plasma processing apparatus comprising a pressure control unit for controlling the pressure so that the ions of the above do not collide with each other in the sheath region. 2. The plasma processing apparatus according to claim 1, wherein the connecting portion includes an electrostatic chuck that electrostatically attracts the substrate to be processed, and a capacitor that is connected to the high frequency oscillator. 3. A matching circuit is connected to the high-frequency oscillator, and the capacitance of the capacitor is determined based on the voltage applied to the matching circuit or the size of a circuit element in the matching circuit. The plasma processing apparatus according to claim 2. 4. The connection part further includes a cooling layer on the back surface of the substrate to be processed.
The plasma processing apparatus according to claim 1. 5. A plasma generating gas is introduced into the plasma processing container, a first high frequency power is applied to the plasma generating gas, and a substrate to be processed placed in the plasma processing container is at a frequency of 13.56 MHz. In the plasma processing method of applying the second high frequency power generated at a high oscillation frequency, the high frequency oscillator for generating the second high frequency power and the substrate to be processed are generated by generating the plasma. Plasma processing characterized in that the pressure in the plasma processing container is set to a pressure at which ions in the plasma do not collide with each other in the sheath region. Method. 6. The plasma processing method according to claim 5, wherein the plasma processing is any one of etching, ashing, cleaning, film formation, surface modification, and impurity introduction.