JP2000294548A - Microwave plasma treatment apparatus using dielectrics window - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma treating device for uniquely and quickly treating a large aperture with high quality, even when treated at a high pressure region of about 1 Torr. SOLUTION: This plasma treatment apparatus is provided with a plasma treatment chamber 101, having a dielectric window 107 through which microwaves are transmitted, a means for supporting a substrate 102 to be treated, a gas inlet means 105 for treatment in the plasma treatment chamber 101, an exhausting means 106 for exhausting the inside part of the plasma treatment chamber 101, and a microwave introducing means having plural slots. The face of the dielectric window 107 at the plasma treatment chamber side is in a drill shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a microwave plasma processing apparatus. More specifically, the present invention relates to 1 Torr
The present invention relates to a microwave plasma processing apparatus capable of performing uniform high-speed and high-quality processing of a large-diameter substrate even in a high pressure range of about r.

[0002]

2. Description of the Related Art A plasma processing apparatus using a microwave as an excitation source for generating plasma includes a CVD apparatus,
An etching device, an ashing device, and the like are known.

[0003] Such a so-called microwave plasma CV
CVD using the D apparatus is performed, for example, as follows.
That is, a gas is introduced into a plasma generation chamber and a film formation chamber of a microwave plasma CVD apparatus, and at the same time, microwave energy is applied to generate plasma in the plasma generation chamber, excite and decompose the gas, and distribute the gas into the film formation chamber. A deposited film is formed on the formed substrate.

[0004] Etching of a substrate to be processed using a so-called microwave plasma etching apparatus is performed, for example, as follows. That is, an etchant gas is introduced into the processing chamber of the apparatus, and at the same time, microwave energy is applied to excite and decompose the etchant gas to generate plasma in the processing chamber, thereby disposing the plasma in the processing chamber. The surface of the substrate to be processed is etched.

The ashing process of a substrate to be processed using a so-called microwave plasma ashing apparatus is performed, for example, as follows. That is, an ashing gas is introduced into the processing chamber of the apparatus, and simultaneously, microwave energy is applied to excite and ablate the ashing gas to generate plasma in the processing chamber, thereby disposing the plasma in the processing chamber. Ashing the surface of the substrate to be processed.

In a microwave plasma processing apparatus,
Since a microwave is used as a gas excitation source, electrons can be accelerated by an electric field having a high frequency, and gas molecules can be efficiently ionized and excited. Therefore, the microwave plasma processing apparatus has the advantages of high gas ionization efficiency, excitation efficiency, and decomposition efficiency, relatively easy formation of high-density plasma, and high-speed processing at low temperature and high speed. In addition, since the microwave has the property of transmitting through the dielectric, the plasma processing apparatus can be configured as an electrodeless discharge type, and therefore, there is an advantage that highly clean plasma processing can be performed.

In order to further increase the speed of such a microwave plasma processing apparatus, an electron cyclotron resonance (EC)
R) has also been put to practical use. The ECR is such that when the magnetic flux density is 87.5 mT, the electron cyclotron frequency at which electrons rotate around the lines of magnetic force is:
Coincides with the general microwave frequency of 2.45 GHz,
This is a phenomenon in which electrons are resonantly absorbed by microwaves, accelerated, and high-density plasma is generated. In such an ECR plasma processing apparatus, the following four configurations are known as typical configurations of the microwave introduction unit and the magnetic field generation unit.

That is, (i) microwaves propagated through the waveguide are introduced into the cylindrical plasma generation chamber from the opposing surface of the substrate through the transmission window, and are coaxial with the central axis of the plasma generation chamber. Configuration in which the diverging magnetic field of the above is introduced via an electromagnetic coil provided around the plasma generation chamber (NTT method);
(Ii) A microwave transmitted through the waveguide is introduced into the bell-shaped plasma generation chamber from the opposite surface of the substrate to be processed, and a magnetic field coaxial with the center axis of the plasma generation chamber is provided around the plasma generation chamber. (Iii) A microwave is introduced into the plasma generation chamber from the periphery through a rigidano coil, which is a kind of cylindrical slot antenna, and the central axis of the plasma generation chamber is introduced. (Rigitano method) in which a magnetic field coaxial with the substrate is introduced through an electromagnetic coil provided around the plasma generation chamber; (iv) microwaves transmitted through the waveguide are flattened from the opposite surface of the substrate to be processed. A configuration in which a loop-shaped magnetic field parallel to the antenna plane is introduced through a permanent magnet provided on the back surface of the planar antenna (plane slot). Antenna system), it is.

As an example of a microwave plasma processing apparatus,
In recent years, a device using an endless annular waveguide having a plurality of slots formed on the H-plane has been proposed as a uniform and efficient microwave introduction device (Patent Publication No. H5-3459).
82, H10-233295). FIG. 3A shows this microwave plasma processing apparatus, and FIG. 3B shows its plasma generation mechanism. Reference numeral 901 denotes a plasma processing chamber; 902, a substrate to be processed; 903, a support for the substrate 902; 904, a substrate temperature adjusting unit; 905, a plasma processing gas introducing unit provided around the plasma processing chamber 901; Reference numeral 907 denotes a flat dielectric window that separates the plasma processing chamber 901 from the atmosphere side, and reference numeral 908 denotes a dielectric window 907 for transmitting microwaves.
911 is an E-branch for distributing microwaves to the left and right, 912 is a slot, and 913 is propagated in the endless annular waveguide 908. 914, a plasma generated by the microwave transmitted through the dielectric window 907 through the slot 912, 915, a microwave surface wave propagating at the interface between the dielectric window 907 and the plasma 914 and causing mutual interference, and 916. Plasma generated by surface wave interference.

The plasma processing is performed as follows. The inside of the plasma processing chamber 901 is evacuated via an exhaust system (not shown). Subsequently, a processing gas is introduced into the plasma processing chamber 901 at a predetermined flow rate through gas introduction means 905 provided around the plasma processing chamber 901. Next, a conductance valve (not shown) provided in an exhaust system (not shown) is adjusted to maintain the inside of the plasma processing chamber 901 at a predetermined pressure. A desired power is supplied from a microwave power supply (not shown) to the plasma processing chamber 901 via the endless annular waveguide 908.
Supply within. At this time, the microwave 913 introduced into the endless annular waveguide 908 is split right and left by the E-branch 911 and propagates with a longer guide wavelength than free space. A high-density plasma 914 is generated by microwaves transmitted through the dielectric window 907 and introduced into the plasma processing chamber 901 through slots 912 provided at every 1/2 or 1/4 of the guide wavelength. In this state, the microwave that has entered the interface between the dielectric window 907 and the plasma 914 cannot propagate into the plasma 914, but propagates as a surface wave 915 at the interface between the dielectric window 907 and the plasma 914. The surface waves 915 introduced from adjacent slots interfere with each other, and form an antinode of the electric field every half of the wavelength of the surface waves 915. The high-density plasma 916 is generated by the anti-node electric field due to the surface wave 915 interference. The processing gas is excited by the generated high-density plasma 916, and processes the surface of the processing object 902 mounted on the support 903.

By using such a microwave plasma processing apparatus, an electron density of 10 ¹² cm ^-3 or more can be obtained in a large-diameter space having a diameter of about 300 μm with a uniformity within ± 3% at a microwave power of 1 kW or more. Since high-density low-potential plasma with a temperature of 3 eV or less and a plasma potential of 20 V or less can be generated, the gas can be sufficiently reacted to be supplied to the substrate in an active state, and substrate surface damage due to incident ions is reduced, so that high quality can be obtained even at a low temperature. And uniform and high-speed processing becomes possible.

[0012]

However, using the microwave plasma processing apparatus as described above, 1 To
When processing is performed in a high pressure region of about rr, gas is introduced and exhausted from the periphery, the supply of gas to the vicinity of the center becomes insufficient, and the processing speed near the center tends to decrease. Occurs.

A main object of the present invention is to solve the above-mentioned problems in the conventional microwave plasma processing apparatus, and
An object of the present invention is to provide a plasma processing apparatus capable of uniformly processing a large-diameter substrate at high speed and high quality even when processing is performed in a high pressure region of about Torr.

[0014]

The above object is achieved by the following means.

That is, the present invention provides a plasma processing chamber having a dielectric window through which microwaves can pass, means for supporting a substrate to be processed, means for introducing a processing gas into the plasma processing chamber, and A plasma processing apparatus comprising an exhaust unit for evacuating and a microwave introducing unit having a plurality of slots, wherein a surface of the dielectric window on a side of the plasma processing chamber is conical. A microwave plasma processing apparatus is proposed, wherein the outer surface of the dielectric window is also conical, and the annular waveguide is also conical along the outer surface of the dielectric window. The gas introducing means is formed so that a gas is blown toward the dielectric window.

According to the present invention, even when processing is performed in a high pressure region of about 1 Torr, a large-diameter substrate can be uniformly processed at high speed and with high quality.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings.

A microwave plasma processing apparatus according to the present invention will be described with reference to FIGS. 1 (a) and 1 (b). 101 is a substantially cylindrical plasma processing chamber, 102 is a flat substrate to be processed, 1
03 is a support of the base 102, 104 is a substrate temperature adjusting means, 105 is a plasma processing gas introducing means provided around the plasma processing chamber 101, 106 is exhaust, and 107 is a part for separating the plasma processing chamber 101 from the atmosphere. A conical dielectric window, 108 is a slotted endless annular waveguide for introducing microwaves into the plasma processing chamber 101 through the dielectric window 107, 111 is an E-branch for distributing microwaves left and right, 112 is a slot, 113 is an endless annular waveguide 10
8, a plasma 114 generated by the microwave transmitted through the dielectric window 107 through the slot 112, and 115 a plasma generated by the dielectric window 107 and the plasma 114.
Surface waves of microwaves that propagate at the interface with
Reference numeral 16 denotes plasma generated by surface wave interference.

The plasma processing is performed as follows. The inside of the plasma processing chamber 101 is exhausted via an exhaust system (not shown). Subsequently, a processing gas is introduced into the plasma processing chamber 101 at a predetermined flow rate through gas introduction means 105 provided around the plasma processing chamber 101. Next, a conductance valve (not shown) provided in an exhaust system (not shown) is adjusted to maintain the inside of the plasma processing chamber 101 at a predetermined pressure. A desired power is supplied from a microwave power supply (not shown) into the plasma processing chamber 101 through the endless annular waveguide 108. At this time, the microwave 113 introduced into the endless annular waveguide 108 is split right and left by the E-branch 111 and propagates with a guide wavelength longer than free space.
A high-density plasma 114 is generated by the microwave introduced into the plasma processing chamber 101 through the dielectric window 107 through the slots 112 provided at every 1/2 or 1/4 of the guide wavelength. In this state, the microwave incident on the interface between the dielectric window 107 and the plasma 114 causes the plasma 11
4, the dielectric window 107 and the plasma 114
And propagates as a surface wave 115. The surface waves 115 introduced from adjacent slots interfere with each other, and form antinodes of the electric field every half of the wavelength of the surface waves 115. A high-density plasma 116 is generated by the antinode electric field due to the interference of the surface wave 115. The processing gas introduced from the periphery is excited, ionized, and reacted by the generated high-density plasma 116 to be activated. Since the conical window-substrate spacing near the center is wide, the processing gas is sufficiently supplied also near the center. 103
The surface of the substrate to be processed 102 placed thereon is uniformly processed.

The shape of the dielectric window 109 used in the microwave plasma processing apparatus of the present invention may be such that at least the inner surface on the plasma processing chamber 110 side is not a perfect plane but is substantially conical. The outer surface may be conical or flat, but it is preferable that the shape of the endless annular waveguide 108 be shaped along the outer surface of the dielectric window 109.

The material of the dielectric window 109 used in the microwave plasma processing apparatus of the present invention can be applied as long as it has a small mechanical loss and a small dielectric loss so that the microwave transmittance is sufficiently high. For example, quartz, alumina (sapphire), aluminum nitride, fluorocarbon polymer and the like are optimal.

The material of the slotted endless annular waveguide 108 used in the microwave plasma processing apparatus of the present invention is as follows.
Any conductor can be used, but in order to minimize microwave propagation loss, Al, Cu,
SUS or the like plated with Ag / Cu is optimal. The direction of the introduction port of the slotted endless annular waveguide 108 used in the present invention is H if the microwave can be efficiently introduced into the microwave propagation space in the slotted endless annular waveguide 108. The distribution may be parallel to the plane and tangential to the propagation space, or may be divided into two in the direction perpendicular to the H plane in the right and left directions of the propagation space at the introduction portion. The slot shape of the slotted endless annular waveguide 108 used in the present invention may be rectangular or elliptical as long as the length in the direction perpendicular to the microwave propagation direction is 1/4 or more of the guide wavelength. It can be in any form. The slot spacing of the slotted endless annular waveguide 108 used in the present invention is optimally ま た は or の of the guide wavelength so that the electric field crossing the slot is enhanced by interference.

Instead of the slotted endless annular waveguide, a radially aligned slot antenna can be used.

The microwave frequency used in the microwave plasma processing apparatus and the processing method according to the present invention is set to 0.
It can be appropriately selected from the range of 8 GHz to 20 GHz.

In the microwave plasma processing apparatus and the processing method of the present invention, a magnetic field generating means may be used for processing at a lower pressure. As the magnetic field used in the plasma processing apparatus and the processing method of the present invention, any magnetic field perpendicular to the electric field generated in the width direction of the slot is applicable. As the magnetic field generating means, a permanent magnet other than a coil can be applied. When using a coil, another cooling means such as a water cooling mechanism or air cooling may be used to prevent overheating.

In order to improve the quality of the treatment, the substrate surface may be irradiated with ultraviolet light. Any light source that emits light absorbed by the substrate to be processed or the gas adhering to the substrate can be used as the light source, and an excimer laser, an excimer lamp, a rare gas resonance line lamp, a low-pressure mercury lamp and the like are suitable.

In the microwave plasma processing method of the present invention, the pressure in the plasma processing chamber is 0.1 mTorr to 1 mTorr.
A range of 0 Torr, more preferably a range of 0.1 Torr to 5 Torr is suitable.

According to the microwave plasma processing method of the present invention,
The formation of a deposited film depends on the appropriate selection of the gas used.
More Si_Three N_Four , SiO_Two , SiOF, Ta_Two O_Five , T
iO _Two , TiN, Al_Two O_Three , AlN, MgF_Two Absolute
Edge film, a-Si, poly-Si, SiC, GaAs, etc.
Semiconductor film, metal film of Al, W, Mo, Ti, Ta, etc.
It is possible to form various deposited films efficiently.
You. When the gas is released toward the dielectric window as shown in FIG.
Still better.

The substrate 102 to be processed by the plasma processing method of the present invention may be a semiconductor, a conductive material, or an electrically insulating material.

As the conductive substrate, Fe, Ni, Cr,
Al, Mo, Au, Nb, Ta, V, Ti, Pt, Pb
And alloys thereof, such as brass and stainless steel.

Examples of the insulating substrate include SiO ₂ -based quartz and various glasses, Si ₃ N ₄ , NaCl, KCl, LiF,
Inorganic substances such as CaF ₂ , BaF ₂ , Al ₂ O ₃ , AlN, MgO, etc., polyethylene, polyester, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyimide and other organic films, sheets, etc. Is mentioned.

The direction of the gas introduction means 105 used in the plasma processing apparatus of the present invention is such that the gas passes through the plasma region generated near the dielectric window 108 and is sufficiently supplied to the vicinity of the center before the substrate surface is moved from the center to the center. It is optimal to have a structure in which a gas can be blown toward the dielectric window 108 so as to flow toward the periphery.

As a gas used for forming a thin film on a substrate by the CVD method, a generally known gas can be used.

S such as a-Si, poly-Si, SiC, etc.
Processing gas introducing means 1 for forming i-type semiconductor thin film
The raw material gas containing Si atoms to be introduced into the plasma processing chamber 101 through the gas supply line 05 is inorganic silanes such as SiH ₄ and Si ₂ H ₆ , tetraethylsilane (TES), tetramethylsilane (TMS), dimethylsilane ( DM
S), organic silanes such as dimethylfluorosilane (DMDFS) and dimethyldichlorosilane (DMDCS),
iF ₄ , Si ₂ F ₆ , Si ₃ F ₈ , SiHF ₃ , SiH
₂ F ₂ , SiCl ₄ , Si ₂ Cl ₆ , SiHCl ₃ , S
Examples include halogenated silanes such as iH ₂ Cl ₂ , SiH ₃ Cl, and SiCl ₂ F ₂ , which are in a gaseous state at normal temperature and normal pressure, or those which can be easily gasified. In this case, the additive gas or carrier gas which may be introduced as a mixture with the Si source gas is H ₂ , He, Ne, Ar, or H ₂ .
Kr, Xe, and Rn.

Si_Three N_Four , SiO_Two Si compound thin such as
Via the processing gas introduction means 105 for forming a film
As a raw material containing Si atoms to be introduced, SiH_Four ,
Si _Two H₆ And other inorganic silanes, tetraethoxysilane
(TEOS), tetramethoxysilane (TMOS),
Kutamethylcyclotetrasilane (OMCTS), Dimethi
Rudifluorosilane (DMDFS), dimethyldichloro
Organic silanes such as silane (DMDCS), SiF_Four , S
i_Two F₆ , Si_Three F₈ , SiHF_Three , SiH_Two F _Two , S
iCl_Four , Si_Two Cl₆ , SiHCl_Three , SiH_Two Cl
_Two , SiH_Three Cl, SiCl_Two F_Two Halogenated sila such as
Components that are in a gaseous state at normal temperature and pressure, or
And those that can be used. Also, in this case,
The nitrogen source gas or oxygen source gas to be introduced is N 2
_Two , NH_Three , N_Two H_Four , Hexamethyldisilazane (HM
DS), O_Two , O_Three , H_Two O, NO, N_Two O, NO_Two etc
Is mentioned.

When a metal thin film of Al, W, Mo, Ti, Ta or the like is formed, the raw material containing a metal atom introduced through the processing gas introducing means 105 is trimethylaluminum (TAMl), triethylaluminum ( T
EAl), triisobutylaluminum (TIBA)
l), dimethyl aluminum hydride (DMAl
H), organic metals such as tungsten carbonyl (W (CO) ₆ ), molybdenum carbonyl (Mo (CO) ₆ ), trimethylgallium (TMGa) and triethylgallium (TEGa), AlCl ₃ , WF ₆ , TiCl ₃ , TaC
metal halide or the like of l _5, and the like. In this case, the additive gas or carrier gas which may be introduced as a mixture with the Si source gas is H ₂ , He, Ne, Ar, or H ₂ .
Kr, Xe, and Rn.

Al_Two O_Three , AlN, Ta_Two O_Five , TiO
_Two , TiN, WO_Three When forming metal compound thin films such as
Atoms Introduced Through Processing Gas Introducing Means 105
The raw material containing trimethylaluminum (T
MAl), triethyl aluminum (TEAl), tri
Isobutylaluminum (TIBAl), dimethylal
Minium hydride (DMAlH), tungsten
Rubonil (W (CO) ₆ ) Molybdenum carbonyl (Mo
(CO)₆ ), Trimethylgallium (TMGa), tri
Organic metal such as ethyl gallium (TEGa), AlCl
_Three , WF₆ , TiCl_Three , TaCl_Five Etc. Halide gold
Genus and the like. In this case, the acid introduced at the same time
As raw material gas or nitrogen raw material gas, O_Two , O_Three ,
H_Two O, NO, N_Two O, NO_Two , N_Two , NH_Three , N_Two H
_Four , Hexamethyldisilazane (HMDS), etc.
You.

Processing gas for etching the substrate surface
As an etching gas introduced from the inlet 105
Is F_Two , CF_Four , CH_Two F_Two , C_Two F₆ , C_Three F₈ ,
C_Four F ₈ , CF_Two Cl_Two , SF₆ , NF_Three , Cl_Two , C
Cl_Four , CH_Two Cl_Two , C_Two Cl₆ And the like.

As the ashing gas introduced from the gas inlet 105 when ashing is performed to remove organic components on the substrate surface such as a photoresist, O ₂ , O ₃ , H ₂ O, N
O, N ₂ O, NO ₂ , H _{2 and the} like can be mentioned.

When the microwave plasma processing apparatus and the processing method of the present invention are also applied to surface modification, by appropriately selecting a gas to be used, for example, Si, Al, Ti, Zn, Ta as a substrate or a surface layer. It is possible to perform oxidation treatment or nitridation treatment of these substrates or surface layers, and doping treatment of B, As, P, etc. Further, the film forming technique employed in the present invention can be applied to a cleaning method. In that case, it can be used for cleaning oxides, organic substances, heavy metals, and the like.

The oxidizing gas introduced through the processing gas inlet 105 when the substrate is subjected to oxidizing surface treatment is O 2
₂ , O ₃ , H ₂ O, NO, N ₂ O, NO _{2 and the} like. The nitriding gas introduced through the processing gas inlet 115 when the substrate is subjected to the nitriding surface treatment may be N 2
₂ , NH ₃ , N ₂ H ₄ , hexamethyldisilazane (HM
DS) and the like.

The cleaning / ashing gas introduced from the gas inlet 105 for cleaning organic substances on the substrate surface or ashing and removing organic components such as photoresist on the substrate surface is O ₂ or O ₂ .
_{3, H 2 O, NO,} N 2 O, NO 2, H 2 , and the like. The cleaning gas introduced from the gas inlet for plasma generation when cleaning the inorganic substance on the surface of the substrate is F ₂ , CF ₄ , CH ₂ F ₂ , C ₂ F ₆ , or the like.
C ₄ F ₈ , CF ₂ Cl ₂ , SF ₆ , NF _{3 and the} like can be mentioned.

(Example of Plasma Processing Apparatus) Hereinafter, the microwave plasma processing apparatus of the present invention will be described more specifically with reference to examples of the apparatus, but the present invention is not limited to these examples.

(Example 1 of Apparatus) An example of the microwave plasma processing apparatus of the present invention will be described with reference to FIG. 101 is a cylindrical plasma processing chamber, 102 is a substrate to be processed, 103 is a support for the substrate 102, 104 is a substrate temperature adjusting means, 10
5 is a plasma processing gas introducing means provided around the plasma processing chamber 101, 106 is exhaust gas, and 107 is a plasma processing chamber 101 for separating the plasma processing chamber 101 from the atmosphere.
A dielectric window having a conical inner surface, and a slotted flat endless annular waveguide 108 for introducing microwaves into the plasma processing chamber 101 through the dielectric window 107.

The material of the dielectric window 107 is anhydrous synthetic quartz.
The outer side is flat and the inner side is conically concave, and the thickness is 20 mm at the periphery and 10 mm at the center. The slotted endless annular waveguide 108 has an inner wall cross-sectional dimension of 27 m.
mx 96 mm, and the center diameter of the waveguide is 202 mm
(Perimeter 4λg). Endless annular waveguide with slot 1
All 08 is made of Al in order to suppress microwave propagation loss. Endless annular waveguide with slot 1
A slot for introducing a microwave into the plasma processing chamber 101 is formed in the H plane 08. The shape of the slot is a rectangular shape having a length of 40 nm and a width of 4 mm, which is discontinuously formed on two straight lines and radially formed at an interval of 1/2 of the guide wavelength. The wavelength in the tube depends on the frequency of the microwave used,
Depending on the cross-sectional dimensions of the waveguide, a frequency of 2.45 G
It is about 159 mm when using a microwave of Hz and a waveguide of the above dimensions. In the used endless annular waveguide with slots 108, eight sets of 16 slots are formed at intervals of about 45 degrees. Endless annular waveguide with slot 1
08 has a 4E tuner, directional coupler, isolator
And a microwave power supply (not shown) having a frequency of 2.45 GHz is connected in order.

The plasma processing is performed as follows. The inside of the plasma processing 101 is evacuated via an exhaust system (not shown). Subsequently, a processing gas is introduced into the plasma processing chamber 101 at a predetermined flow rate through gas introduction means 105 provided around the plasma processing chamber 101. Next, a conductance valve (not shown) provided in an exhaust system (not shown) is adjusted to maintain the inside of the plasma processing chamber 101 at a predetermined pressure. A desired power is supplied from a microwave power supply (not shown) into the plasma processing chamber 101 through the endless annular waveguide 108. At this time, the processing gas released obliquely upward from the periphery is excited and generated by the generated high-density plasma.
It is activated by ionization and reaction. Since the conical window-substrate spacing near the center is wide, it is sufficiently supplied also near the center to uniformly treat the surface of the substrate 102 placed on the support 103.

(Example 2 of Apparatus) An example of the microwave plasma processing apparatus of the present invention will be described with reference to FIG. Reference numeral 201 denotes a cylindrical plasma processing chamber; 202, a substrate to be processed; 203, a support for the substrate 202;
5 is a plasma processing gas introducing means provided around the plasma processing chamber 201, 206 is an exhaust gas, 207 is a dielectric window having a conical shape on both sides for separating the plasma processing chamber 201 from the atmosphere side, and 208 is a microwave. A slotted conical endless annular waveguide for introduction into the plasma processing chamber 201 through the dielectric window 207.

The material of the dielectric window 207 is anhydrous synthetic quartz.
Both sides have a conical shape, a thickness of 17 mm, and a center recessed by 10 mm from the periphery. Endless annular waveguide with lot 20
8 also has a conical shape along the dielectric window 207, has a waveguide inner wall cross-sectional dimension of 27 mm × 96 mm, and has a waveguide center diameter of 202 mm (perimeter of 4λg). The material of the slotted endless annular waveguide 208 is all Al in order to suppress microwave propagation loss. Slots for introducing microwaves into the plasma processing chamber 201 are formed on the H surface of the slotted endless annular waveguide 208. The shape of the slot is rectangular, having a length of 40 nm and a width of 4 mm, and is formed discontinuously on two straight lines and radially at an interval of 1/2 of the guide wavelength. The guide wavelength depends on the frequency of the microwave used and the size of the cross section of the waveguide, and when the microwave having the frequency of 2.45 GHz and the waveguide having the above dimensions are used, about 159 mm is used. It is. In the slotted endless annular waveguide 208 used, the slot is approximately 45
Eight sets of 16 are formed at an interval of degrees. The slotted endless annular waveguide 208 includes a 4E tuner, a directional coupler,
An isolator and a microwave power supply (not shown) having a frequency of 2.45 GHz are sequentially connected.

The plasma processing is performed as follows. The inside of the plasma processing 201 is evacuated via an exhaust system (not shown). Subsequently, a processing gas is introduced into the plasma processing chamber 201 at a predetermined flow rate through gas introduction means 205 provided around the plasma processing chamber 201. Next, a conductance valve (not shown) provided in an exhaust system (not shown) is adjusted to maintain the inside of the plasma processing chamber 201 at a predetermined pressure. A desired power is supplied from a microwave power supply (not shown) into the plasma processing chamber 201 through the endless annular waveguide 208. At this time, the processing gas discharged obliquely upward from the periphery is excited, ionized, and activated by the generated high-density plasma, and the conical window-substrate spacing near the center is wide. The surface of the substrate 202 to be processed supplied and placed on the support 203 is uniformly processed.

[0050]

EXAMPLES Hereinafter, the microwave plasma processing apparatus and the processing method of the present invention will be described more specifically with reference to examples.
The present invention is not limited to these examples.

Example 1 Ashing of a photoresist was performed using the microwave plasma processing apparatus shown in FIG.

As the substrate 102, silicon (S) immediately after the interlayer SiO ₂ film was etched and via holes were formed.
i) A substrate (φ12 inch) was used. First, after setting the Si substrate 102 on the base support 103, the heater 10
4 and heated to 200 ° C., and the inside of the plasma processing chamber 101 was evacuated via an exhaust system (not shown) to 10 ⁻⁴ To.
The pressure was reduced to rr. Gas inlet 105 for plasma processing
Oxygen gas at a flow rate of 2 slm through the plasma processing chamber 1
01. Next, a conductance valve (not shown) provided in an exhaust system (not shown) was adjusted to maintain the inside of the processing chamber 101 at 1 Torr. Plasma processing chamber 10
2.5k from 2.45GHz microwave power supply within 1.
W power was supplied through the slotted endless annular waveguide 108. Thus, plasma was generated in the plasma processing chamber 101. At this time, the plasma processing gas inlet 1
Oxygen gas introduced through the plasma processing chamber 10
Excited, decomposed and reacted in 1 to form ozone, transported in the direction of the silicon substrate 102, oxidized the photoresist on the substrate 102, and vaporized and removed. After ashing, the ashing speed, the substrate surface charge density, and the like were evaluated.

The uniformity of the obtained ashing speed is ±
It was extremely large at 4.2% (7.5 μm / min), and the surface charge density was a sufficiently low value of 0.5 × 10 ¹¹ cm ⁻² .

Example 2 Photoresist ashing was performed using the microwave plasma processing apparatus shown in FIG.

As the substrate 202, silicon (S) immediately after the interlayer SiO ₂ film was etched and via holes were formed.
i) A substrate (φ12 inch) was used. First, after placing the Si substrate 202 on the base support 203, the heater 20
4 and heated to 200 ° C., and the inside of the plasma processing chamber 201 was evacuated via an exhaust system (not shown) to 10 ^-5 To.
The pressure was reduced to rr. Gas inlet 205 for plasma processing
Oxygen gas at a flow rate of 2 slm through the plasma processing chamber 1
01. Next, a conductance valve (not shown) provided in an exhaust system (not shown) was adjusted to maintain the inside of the processing chamber 201 at 2 Torr. Plasma processing chamber 20
2.5k from 2.45GHz microwave power supply within 1.
W power was supplied via slotted endless annular waveguide 208. Thus, plasma was generated in the plasma processing chamber 201. At this time, the plasma processing gas inlet 2
Oxygen gas introduced through the plasma processing chamber 20
Excited, decomposed and reacted in 1 to form ozone, transported in the direction of the silicon substrate 202, oxidized the photoresist on the substrate 202, and vaporized and removed. After ashing, the ashing speed, the substrate surface charge density, and the like were evaluated.

The uniformity of the obtained ashing speed is ±
It was extremely large at 4.8% (8.6 μm / min), and the surface charge density was a sufficiently low value of 1.2 × 10 ¹¹ cm ⁻² .

Example 3 Using the microwave plasma processing apparatus shown in FIG. 1, a silicon nitride film for protecting a semiconductor element was formed.

As the base 102, a φ300 mm P-type single crystal silicon substrate (plane orientation <100>, resistivity 10 Ωcm) with an interlayer SiO ₂ film on which an Al wiring pattern (line and space 0.5 μm) was formed was used.
First, after the silicon substrate 102 is set on the substrate support 103, the plasma processing chamber 10 is set through an exhaust system (not shown).
The inside of 1 was evacuated and the pressure was reduced to 10 ^-7 Torr.
Subsequently, a current is supplied to the heater 104 so that the silicon substrate 102
The substrate was heated to 00 ° C. and kept at this temperature. Nitrogen gas is supplied through the plasma processing gas inlet 105 for 600 seconds.
At a flow rate of ccm, and a monosilane gas of 200 scc
It was introduced into the processing chamber 101 at a flow rate of m. Next, a conductance valve (not shown) provided in an exhaust system (not shown) was adjusted to maintain the inside of the processing chamber 101 at 20 mTorr. Then, 3.0 kW of power was supplied from a 2.45 GHz microwave power supply (not shown) via the slotted endless annular waveguide 108. Thus, plasma was generated in the plasma processing chamber 101. At this time, the nitrogen gas introduced through the plasma processing gas inlet 105 is excited and decomposed into active species in the plasma processing chamber 101, is transported in the direction of the silicon substrate 102, reacts with the monosilane gas, and reacts with the silicon nitride. A film was formed on the silicon substrate 102 with a thickness of 1.0 μm. After the film formation, film quality such as film formation speed and stress was evaluated. The stress was determined by measuring the change in the amount of warpage of the substrate before and after film formation using a laser interferometer Zygo (trade name).

The uniformity of the obtained silicon nitride film is as large as ± 2.2% (580 nm / min), the film quality is 1.1 × 10 ⁹ dyne · cm ⁻² (compression), and the leakage is uniform. It was confirmed that the film was a very good film having a current of 1.2 × 10 ⁻¹⁰ A · cm ⁻² and a withstand voltage of 10.3 MV / cm.

Example 4 Using the microwave plasma processing apparatus shown in FIG. 2, a silicon oxide film and a silicon nitride film for preventing plastic lens reflection were formed.

As the substrate 202, a plastic convex lens was used. After the lens 202 is set on the substrate support 203, the plasma processing chamber 2 is set via an exhaust system (not shown).
01 was evacuated, and the pressure was reduced to a value of 10 ^-7 Torr. Nitrogen gas is supplied at a flow rate of 150 sccm through the gas inlet 205 for plasma processing,
It was introduced into the processing chamber 201 at a flow rate of 0 sccm. Next, a conductance valve (not shown) provided in an exhaust system (not shown) is adjusted to evacuate the processing chamber 201 to 5 mTorr.
Held. Next, power of 3.0 kW was supplied from a 2.45 GHz microwave power supply (not shown) into the plasma processing chamber 201 through the slotted endless annular waveguide 208. Thus, plasma was generated in the plasma processing chamber 201. At this time, the plasma processing gas inlet 205
Nitrogen gas introduced through the plasma processing chamber 201
Is excited and decomposed into active species such as nitrogen atoms, is transported in the direction of the lens 202, reacts with monosilane gas,
A silicon nitride film was formed on the lens 202 with a thickness of 20 nm.

Next, oxygen gas and monosilane gas were introduced into the processing chamber 201 through the plasma processing gas inlet 205 at a flow rate of 200 sccm and a monosilane gas at a flow rate of 100 sccm. Then, a contactance valve (not shown) provided in an exhaust system (not shown) was adjusted to maintain the inside of the processing chamber 201 at 1 mTorr. Next, a power of 2.0 kW from a microwave power supply (not shown) of 2.45 GHz is supplied to the plasma generation chamber 2 through the slotted endless annular waveguide 208.
01. Thus, plasma was generated in the plasma processing chamber 201. At this time, the oxygen gas introduced through the plasma processing gas introduction port 205 is excited and decomposed in the plasma processing chamber 201 to become active species such as oxygen atoms, is transported in the direction of the glass substrate 202, and is reacted with the monosilane gas. As a result, a silicon oxide film was formed on the glass substrate 202 with a thickness of 85 nm. After the film formation, the film formation speed and the reflection characteristics were evaluated.

The uniformity of the deposition rates of the obtained silicon nitride film and silicon oxide film was ± 2.6% (350 n
m / min) and ± 2.6% (390 nm / min), and the film quality was confirmed to be very good optical characteristics with a reflectance around 500 nm of 0.17%.

Example 5 Using the microwave plasma processing apparatus shown in FIG. 1, a silicon oxide film for interlayer insulation of a semiconductor element was formed.

As the substrate 102, a φ having an Al pattern (line and space 0.5 μm) formed at the uppermost portion was used.
300 mm P-type single crystal silicon substrate (plane orientation <10
0>, resistivity 10 Ωcm). First, the silicon substrate 102 was set on the base support 103. The inside of the plasma processing chamber 101 was evacuated via an exhaust system (not shown) to reduce the pressure to a value of 10 ^-7 Torr. Subsequently, the heater 104 was energized to heat the silicon substrate 102 to 300 ° C., and the substrate was kept at this temperature. Oxygen gas was introduced into the processing chamber 101 at a flow rate of 500 sccm and monosilane gas at a flow rate of 200 sccm through the plasma processing gas inlet 105. Next, the conductance valve (not shown) provided in the exhaust system (not shown) is adjusted,
The inside of the processing chamber 101 was maintained at 30 mTorr. Then
A power of 300 W is applied to the substrate support 102 through a 400 kHz high-frequency application unit, and a power of 2.45 GHz is applied.
2.5 kW of power from the microwave power source of z through the slotted endless annular waveguide 108 to the plasma processing chamber 101.
Supplied within. Thus, plasma was generated in the plasma processing chamber 101. Gas inlet 105 for plasma processing
The oxygen gas introduced through the plasma processing chamber 101 is excited and decomposed in the plasma processing chamber 101 to become active species, and the silicon substrate 102
And reacted with the monosilane gas to form a silicon oxide film on the silicon substrate 102 with a thickness of 0.8 μm. At this time, the ion species is accelerated by the RF bias and is incident on the substrate to cut the film on the pattern to improve the flatness. After the treatment, the film formation rate, uniformity, dielectric strength, and step coverage were evaluated. The step coverage was evaluated by forming a film on the Al wiring pattern, observing the cross section of the silicon oxide film with a scanning electron microscope (SEM), and observing voids.

The uniformity of the obtained silicon oxide film is as good as ± 2.5% (290 nm / min), the film quality is 9.1 MV / cm, the film quality is void-free, and it is a good film. It was confirmed that.

Embodiment 6 Using the microwave plasma processing apparatus shown in FIG. 2, the SiO ₂ film between semiconductor elements was etched.

As the substrate 202, a 1 μm thick interlayer S was formed on an Al pattern (line and space 0.35 μm).
A φ300 mm P-type single crystal silicon substrate (plane orientation <100>, resistivity 10 Ωcm) on which an iO ₂ film was formed was used. First, the silicon substrate 202 was set on the base support 203. Etching chamber 20 via an exhaust system (not shown)
The inside of 1 was evacuated, and the pressure was reduced to 10 ^-7 Torr. CF ₄ was introduced into the plasma processing chamber 201 through the plasma processing gas inlet 205 at a flow rate of 300 sccm. Next, the conductance valve (not shown) provided in the exhaust system (not shown) is adjusted, and the plasma processing chamber 20 is adjusted.
1 was maintained at a pressure of 5 mTorr. Then 400
A power of 300 W is applied to the substrate support 202 via a high-frequency applying means of kHz, and a power of 3.0 kW is applied from a microwave power supply of 2.45 GHz to the plasma processing chamber through an endless annular waveguide 208 with slots. 201. Thus, plasma was generated in the plasma processing chamber 201. The F ₄ gas introduced through the plasma processing gas introduction port 205 is excited and decomposed into an active species in the plasma processing chamber 201, is transported in the direction of the silicon substrate 202, and is intercalated by ions accelerated by a self-bias. The SiO ₂ film was etched. Cooler 2
04 caused the substrate temperature to rise only to 90 ° C.
After the etching, the etching rate, the selectivity, and the etching shape were evaluated. The etched shape is obtained by scanning the cross section of the etched silicon oxide film with a scanning electron microscope (S
(EM) and evaluated.

The uniformity of the etching rate and the selectivity to polysilicon were as good as ± 2.4% (720 nm / min) and 20. It was confirmed that the etching shape was almost vertical and the microloading effect was small.

Example 7 Using the microwave plasma processing apparatus shown in FIG. 1, the polysilicon film between the gate electrodes of the semiconductor elements was etched.

As the base 102, a φ300 mm P-type single crystal silicon substrate (plane orientation <100>, resistivity 10 Ωcm) having a polysilicon film formed on the top was used.
First, the silicon substrate 102 was set on the base support 103. The inside of the plasma chamber 101 was evacuated through an exhaust system (not shown) to reduce the pressure to a value of 10 ^-7 Torr. 300 s of CF ₄ through the plasma processing gas inlet 105
ccm and oxygen at a flow rate of 20 sccm
01. Next, a conductance valve (not shown) provided in an exhaust system (not shown) was adjusted to maintain the inside of the plasma processing chamber 101 at a pressure of 2 mTorr. Then, a high-frequency power of 300 W is applied from a 400-kHz high-frequency power supply (not shown) to the substrate support 103, and a 2.0-kW microwave power supply of 2.45 GHz is used.
Was supplied into the plasma processing chamber 101 via the slotted endless annular waveguide 108. Thus, plasma was generated in the plasma processing chamber 101. CF ₄ gas and oxygen introduced through the plasma processing gas inlet 105 are excited and decomposed in the plasma processing chamber 101 to become active species, transported in the direction of the silicon substrate 102, and accelerated by self-bias As a result, the polysilicon film was etched. The cooler 104 increased the substrate temperature only up to 80 ° C. After the etching, the etching rate, the selectivity, and the etching shape were evaluated. The etched shape was evaluated by observing the cross section of the etched polysilicon film with a scanning electron microscope (SEM).

The uniformity of the etching rate and the selectivity to SiO ₂ were as good as ± 2.7% (850 nm / min) and 24.
It was confirmed that the etching shape was almost vertical and the micro-rotating effect was small.

[0073]

As described above, according to the present invention,
Since the surface of the dielectric window on the side of the plasma processing chamber is not a perfect flat plate but a cone, even when processing is performed in a high pressure region of about 1 Torr, a large-diameter substrate can be uniformly processed at high speed and high quality. There is an effect that a plasma processing apparatus can be provided.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) show a microwave plasma processing apparatus using a slotted endless annular waveguide using a dielectric window having a conical inner surface on one side, which is an example of the present invention. FIG.

FIG. 2 is a schematic view of a microwave plasma processing apparatus using a slotted endless annular waveguide using a dielectric window having a conical shape on both sides, which is an example of the present invention.

FIGS. 3A and 3B are schematic views of a microwave plasma processing apparatus as a conventional example.

[Explanation of symbols]

101, 201, 901 Plasma processing chambers 102, 202, 902 Substrates 103, 203, 903 Supports 104, 204, 904 Substrate temperature adjusting means (cooler) 105, 205, 905 Processing gas introducing means 106, 206, 906 Exhaust 107, 207, 907 Dielectric windows 108, 208, 908 Slotted endless annular waveguide 911, 111 E-branch 912, 112 Slot 913, 113 Microwave propagating in waveguide 914, 114 Plasma generated just below slot 915,115 Surface waves propagating at the interface between dielectric window and plasma 916,116 Plasma generated by interference between surface waves

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/3065 H05H 1/46 B H05H 1/46 C H01L 21/302 BF Term (Reference) 4K030 AA06 AA18 BA40 BA44 CA04 CA07 DA08 FA01 KA46 LA00 LA02 LA15 LA24 4K057 DA16 DB01 DB02 DB03 DB04 DB05 DB06 DB08 DC10 DD01 DE06 DE07 DE08 DE09 DE15 DE20 DG06 DK03 DM29 DN01 5F004 AA01 AA15 BA20 BB14 BB28 BC03 AB01 AB04 AB26 AB03 AB04 AB33 AB34 AE13 AE15 AE17 AE19 AE21 BB01 EB02 EC05 EE20 EF03 EH02 EH03 EH16 EH19 EK12 EK17

Claims (3)

[Claims] 1. A plasma processing chamber having a dielectric window through which microwaves can pass, supporting means for supporting a substrate to be processed, processing gas introducing means into the plasma processing chamber, and exhaust means for exhausting the plasma processing chamber. And a microwave introducing means having a plurality of slots, wherein the surface of the dielectric window on the side of the plasma processing chamber is conical. 2. The plasma processing apparatus according to claim 1, wherein the outer surface of the dielectric window is also conical, and the annular waveguide is conical along the outer surface of the dielectric window. 3. The plasma processing apparatus according to claim 1, wherein said processing gas introducing means is formed such that a gas is blown toward said dielectric window.