JP2003142471A - Plasma treatment apparatus and method of manufacturing constitutional body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma treatment apparatus which can control radiation damage by reducing the amount of radiation of a microwave to a substrate even in an initial condition of discharge. SOLUTION: The plasma treatment apparatus which performs plasma treatment by evacuating an almost cylindrical plasma treatment chamber 101 with an evacuation means 106, introducing the microwave into the plasma treatment chamber 101 via a microwave waveguide 108, and generating plasma in the plasma treatment chamber 101. In this plasma treatment apparatus, the microwave conversion distance between the surface of a plasma treated object 102 and the microwave waveguide 108 is set almost to quarter of add numbers of an natural wavelength. Moreover, the microwave is introduced into the plasma treatment chamber 101 via a dielectric material window 107. The microwave conversion thickness of the dielectric material window 107 is equal to the value obtained by multiplying the actual thickness of the dielectric material window 107 with a square root value of the specific dielectric constant of the dielectric material window 107 at the frequency of the microwave introduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus and a method for manufacturing a structure, in which plasma is generated by using microwaves for processing.

[0002]

2. Description of the Related Art As a plasma processing apparatus using microwaves as an excitation source for generating plasma, an optical component, L
A CVD apparatus, an etching apparatus, an ashing apparatus, etc., which are used in manufacturing processes of structures such as SI, flat panel displays, and micromechanics are known.

Such so-called microwave plasma CV
The CVD using the D apparatus is performed as follows, for example.
That is, a gas for plasma generation is introduced into the plasma generation chamber and the film formation chamber of the microwave plasma CVD apparatus, and at the same time, microwave energy is input to generate plasma in the plasma generation chamber to excite and decompose the gas, thereby forming the gas. A deposited film is formed on the object to be processed arranged in the film chamber.

Further, the etching process of the object 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 processing body is etched.

Further, the ashing process of the object to be processed using the so-called microwave plasma ashing device is performed as follows, for example. That is, 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. Ashing the surface of the processing body.

In a plasma processing apparatus for generating plasma using microwaves, since microwaves are 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, Can be excited. Therefore, the plasma processing apparatus using microwaves has the advantages of high ionization efficiency, excitation efficiency and decomposition efficiency of gas, relatively high density plasma formation, and high-speed processing at low temperature. Have.

Further, since the microwave has a property of transmitting the dielectric, the plasma processing apparatus can be constructed as an electrodeless discharge type, which has an advantage that a highly clean plasma processing can be performed.

In order to further increase the speed of such a microwave plasma processing apparatus, electron cyclotron resonance (EC
A plasma processing apparatus utilizing R) has also been put into practical use. When the magnetic flux density is 87.5 mT, the ECR shows that the electron cyclotron frequency at which electrons rotate around the lines of magnetic force is
It matches the general frequency of microwaves of 2.45 GHz,
This is a phenomenon in which electrons are resonantly absorbed by microwaves and accelerated, and high-density plasma is generated.

Separately from this, as an example of a microwave plasma processing apparatus, in recent years, an apparatus using an endless annular waveguide having a plurality of slots formed therein has been proposed as an apparatus for uniformly and efficiently introducing microwaves. (Japanese Patent Laid-Open No. 5-3
45982, JP-A-10-233295). This microwave plasma processing apparatus is shown in FIG.
FIG. 5B shows the plasma generating mechanism. 901
Is a plasma processing chamber, 902 is an object to be processed, 903 is a support for the object to be processed 902, 904 is substrate temperature adjusting means, and 905.
Is a plasma processing gas introduction means provided around the plasma processing chamber 901, 906 is exhaust gas, 907 is a flat dielectric window for separating the plasma processing chamber 901 from the atmosphere side, 908.
Is a slotted endless annular waveguide for introducing microwaves into the plasma processing chamber 901 through the dielectric window 907,
911 is an E branch that splits the microwave into left and right, 912 is a standing wave generated inside the endless annular waveguide 908, 913 is a slot, 914 is a surface wave propagating on the surface of the dielectric window 907, and 915 is an adjacent slot. Is a surface standing wave generated by the interference of the surface waves introduced from each other, 916 is a surface plasma generated by the surface standing wave 915, and 917 is a bulk plasma generated by the diffusion of the surface plasma 916.

Plasma processing using the above apparatus is performed as follows. The inside of the plasma processing chamber 901 is evacuated through an exhaust system (not shown). Subsequently, a processing gas is introduced into the plasma processing chamber 901 by a gas introduction means 90 provided around
5 is introduced into the plasma processing chamber 901 at a predetermined flow rate. Next, a conductance valve (not shown) provided in the 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 source (not shown) into the plasma processing chamber 901 through the endless annular waveguide 908. At this time, the microwave introduced into the endless annular waveguide 908 is divided into two parts on the left and right by the E branch 911, and propagates with a guide wavelength longer than the free space. The distributed microwaves interfere with each other to generate "antinodes" of standing waves for each 1/2 of the in-tube wavelength.

A slot 913 is formed by a microwave that is transmitted through the dielectric window 907 and introduced into the plasma processing chamber 901 through the slot 913 provided so as to cross the surface current.
Initial high-density plasma is generated in the vicinity. In this state, the microwave incident on the interface between the dielectric window 907 and the initial high-density plasma cannot propagate in the initial high-density plasma, and the surface wave 91 is generated on the interface between the dielectric window 907 and the initial high-density plasma.
Propagate as 4.

Surface waves 9 introduced from adjacent slots
14 interfere with each other to generate a surface standing wave 915 having an “antinode” for each half of the wavelength of the surface wave 914. Surface plasma 916 is generated by this surface standing wave 915. Further, bulk plasma 917 is generated by diffusion of surface plasma 916. The processing gas is excited by the generated surface wave interference plasma and processes the surface of the object 902 to be processed which is fixedly placed on the support 903.

By using such a microwave plasma processing apparatus, with a microwave power of 1 kW or more, an electron density of 10 ¹² cm ^-3 or more, an electron density of 10 ¹² cm ^-3 or more can be obtained in a large diameter space of about 300 mm with uniformity. Since a high-density low-potential plasma having a temperature of 3 eV or less and a plasma potential of 15 V or less can be generated, a gas can be sufficiently reacted to be supplied to an object to be processed in an active state, and substrate surface damage due to incident ions can be reduced. High quality, uniform and high speed processing becomes possible.

[0014]

However, when plasma processing is performed using the microwave plasma processing apparatus as described above, if plasma having a cutoff density or higher is generated, the microwave processing object is directed toward the processing object. However, the microwave may propagate to the object to be processed when the discharge is not generated and the density is low at the initial stage of the discharge, and damage may occur due to the irradiation of the microwave.

The present invention has been made in view of the above points, and an object of the present invention is to provide a plasma processing apparatus capable of reducing microwave irradiation to a substrate and suppressing irradiation damage even at the initial stage of discharge.

[0016]

In order to solve the above problems, the present invention is directed to plasma treatment by introducing microwaves into a plasma treatment chamber through a microwave waveguide and generating plasma in the plasma treatment chamber. In the plasma processing apparatus for performing the above, the microwave-converted distance between the surface of the object to be plasma-processed and the microwave waveguide is an odd multiple of about ¼ of the natural wavelength.

Further, according to the present invention, the substantially cylindrical plasma processing chamber is evacuated by the exhaust means, the microwave is introduced into the plasma processing chamber through the microwave introducing pipe, and the plasma is generated in the plasma processing chamber. In the plasma processing apparatus, a microwave that reflects the microwave reflected on the surface of the object to be processed at a position that is an odd multiple of a quarter of the natural wavelength of the microwave at a microwave conversion distance from the surface of the object to be processed by plasma. It is characterized by comprising a reflecting means.

Further, according to the present invention, in a plasma processing apparatus for introducing a high frequency wave into the plasma processing chamber through a high frequency supply device to generate plasma in the plasma processing chamber, the high frequency emission device for high frequency emission is formed. It is characterized by having a plasma detection element for detecting plasma through the slot. The slot is preferably provided on a slot plate arranged in parallel with the surface to be processed of the object to be processed, and control for stopping the supply of microwaves based on the detection result of the plasma detection element is performed. It is preferable to further include a device.

In addition, the present invention is a method of manufacturing a structure having a step of plasma-treating a surface of a substrate on which the structure is to be formed, wherein the plasma treatment is performed by using the plasma treatment apparatus described above. And

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The basic concept of the present invention will be described below with reference to FIG. Reference numeral 101 denotes a plasma processing chamber whose inner wall has a substantially cylindrical shape, 102 denotes an object to be processed, 103 denotes a support for the object to be processed 102, 104 denotes substrate temperature adjusting means,
Reference numeral 5 is a plasma processing gas introduction means provided around the plasma processing chamber 101, 106 is an exhaust gas, 107 is a dielectric window for separating the plasma processing chamber 101 from the atmosphere side, and 108 is a dielectric window for microwaves of high frequency. An endless annular waveguide with a slot as a high-frequency feeder for introduction into the plasma processing chamber 101 through 107, a microwave reflecting member as a microwave reflecting means, 111 an E branch for dividing the microwave into left and right, 112 is a standing wave generated inside the endless annular waveguide 108, 113 is a slot, 114
Is a surface wave propagating on the surface of the dielectric window 107 through the slot 113, 115 is a surface standing wave generated by interference between surface waves 114 introduced from the adjacent slots 113, 1
16 is a surface plasma generated by the surface standing wave 115,
Reference numeral 17 is a bulk plasma generated by diffusion of surface plasma. Reference numeral 121 is a plasma detection element including a light receiving element and the like provided above an arbitrary slot 113, and a conductive upper wall constituting the detection light transmitting dielectric window 107, the slot 113 and the endless annular waveguide 108. Plasma light is monitored through a through hole formed in the. Detection element 1
Reference numeral 21 is connected to a control device (not shown), and the processing state can be controlled by observing the plasma in situ. For example, the detection element 121 can be used as a malfunction detection monitor that detects malfunction such as non-generation of plasma, or an endpoint monitor for appropriately ending plasma processing. Microwave reflection member 109
Is the upper surface of the object support 103 and the endless annular waveguide 10.
8 When the microwave conversion interval with the lower surface (that is, the lower surface of the conductive slot plate 120 in which the slot 113 is formed) is set to an odd multiple of ¼ of the natural wavelength of the microwave, it may not be used.

The plasma treatment is performed as follows. The inside of the plasma processing chamber 101 is evacuated via an exhaust system (not shown). Subsequently, the processing gas is introduced into the plasma processing chamber 101 at a predetermined flow rate through the gas introduction means 105 provided around the plasma processing chamber 101. Next, a conductance valve (not shown) provided in the exhaust system (not shown) is adjusted to maintain the inside of the plasma processing chamber 101 at a predetermined pressure. A desired power from a microwave power source (not shown) is passed through the endless annular waveguide 108 to the plasma processing chamber 101.
Supply in. At this time, the microwaves introduced into the endless annular waveguide 108 are distributed to the left and right by the E branch 111, and propagate with a guide wavelength longer than the free space. The distributed microwaves interfere with each other, resulting in about 1/2 of the guide wavelength.
Each produces a standing wave 112 having an "antinode". Microwaves are introduced into the plasma processing chamber 101 through the dielectric window 107 through the slot 113 provided so as to cross the surface current.

At this time, the microwave propagates in the direction of the object 102 to be processed until the plasma having the cut-off density or higher is generated, but the microwave between the upper surface of the object support 103 and the lower surface of the endless annular waveguide 108 is maintained. Set the wave conversion interval to an odd multiple of about 4 minutes of the microwave natural wavelength, or
If the microwave reflecting means 109 for reflecting microwaves toward the object support 103 is formed at a position at an odd multiple of 3/4 from the natural wavelength of the microwave, the object to be processed 10
It is possible to suppress the excitation of the standing wave right above the support 103 of the object to be processed, by weakening and interfering with each other in the two directions and the one reflected by the object to be processed 102. Thereby, the object to be processed 10
It is possible to reduce the irradiation of microwaves on the second.

The microwave introduced into the plasma processing chamber 101 generates initial high density plasma in the vicinity of the slot 113. In this state, the microwave incident on the interface between the dielectric window 107 and the initial high-density plasma cannot propagate in the initial high-density plasma, and propagates on the interface between the dielectric window 107 and the initial high-density plasma as a surface wave 114. To do.

Surface wave 1 introduced from an adjacent slot
14 interfere with each other, and are about 1/2 of the wavelength of the surface wave 114.
Each produces a surface standing wave 115 having an "antinode". A surface plasma 116 is generated by the surface standing wave 115. Further, bulk plasma 117 is generated by diffusion of surface plasma 116. The processing gas is excited by the generated surface wave interference plasma, and processes the surface of the object to be processed 102 fixedly placed on the support 103.

Since the state of the plasma can be monitored by the detection element 121, if the desired plasma is not generated even after a lapse of a predetermined time after the start of supplying the microwave, the microwave is detected based on the monitoring result. The supply can be stopped to interrupt the processing operation. Even in such a case, it is possible to prevent microwave damage to the object to be processed. In particular, when the detection element is arranged at the above-mentioned position, the plasma in the vicinity of the slot 113, which is a source of the microwave supplied to the processing chamber, can be observed, so that more accurate plasma observation can be performed. Since there are a plurality of slots, the detecting element 121 may be provided at each of two or more slots.

Further, when performing processing such as etching and ashing, the emission state of plasma may change around the end of the desired processing depending on the atoms forming the surface to be processed. Then, the processing can be terminated by, for example, stopping the supply of the microwave.

The microwave conversion distance from the upper surface of the object support 103 to the lower surface of the endless annular waveguide 108 is obtained by multiplying the actual thickness by the square root of the relative permittivity of each material with respect to the frequency of the introduced microwave. The converted thickness is the total for each material. Microwave frequency is usually 300MHz
However, the frequency used in the embodiment is such that the wavelength is approximately the same as the reactor size, 1 to 1
About 0 GHz is particularly effective.

The microwave reflection means is used in the plasma processing chamber 1
Any reflective structure in the direction of the support 103 of the object to be processed having an area of about 5% or more of the cross-sectional area of 01 can be applied, and a simple reflective surface, a structure protruding like an eaves, or a groove can be entered. Alternatively, it may be in the form of a mesh having a hole diameter of about 1/8 or less of the natural wavelength of microwaves.

The dielectric window 109 may be made of any material as long as it has a small dielectric loss so as to have a sufficient mechanical strength and a sufficiently high microwave transmittance. For example, quartz, alumina, sapphire or aluminum nitride may be used. , Fluorocarbon polymers, etc. are applicable.

As the material of the endless annular waveguide 108 with a slot and the slot plate 120 which constitute the high frequency feeder, a conductive material can be used, but in order to suppress microwave propagation loss as much as possible, the conductivity of High Al, Cu, Ag
The most suitable is SUS plated with / Cu. The direction of the introduction port of the slotted endless annular waveguide 108 is parallel to the H-plane as long as the microwave can be efficiently introduced into the microwave propagation space in the slotted endless annular waveguide 108. It may be a tangential direction of the space or a direction perpendicular to the H plane and distributed in the lateral direction of the propagation space at the introduction portion.

The shape of the slot of the endless annular waveguide 108 with a slot may be rectangular, elliptical or array-shaped as long as the length in the direction perpendicular to the microwave propagation direction is about ¼ of the guide wavelength. Anything is fine. The slot spacing of the endless annular waveguide with slot 108 used in the embodiment is optimally ½ of the guide wavelength so that the electric fields crossing the slots are mutually strengthened by interference.

A magnetic field generating means may be used in order to carry out the treatment under a lower pressure. The magnetic field used is
A magnetic field perpendicular to the electric field generated in the width direction of the slot can be applied. As the magnetic field generating means, a permanent magnet other than a coil can be used. When using a coil, other cooling means such as a water cooling mechanism or air cooling may be used to prevent overheating.

Further, in order to improve the quality of the treatment, the surface of the object to be treated may be irradiated with ultraviolet light. The light source is applicable as long as it emits light absorbed by the object to be processed or the gas attached to the object to be processed, and an excimer laser, an excimer lamp, a rare gas resonance line lamp, a low-pressure mercury lamp, etc. are suitable. .

The pressure inside the plasma processing chamber is 1.33 × 10.
^-2 Pa to 13.3 × 10 ² Pa, more preferably 1.33 Pa to 6.65 × 10 ² P
A range of about a is suitable.

The deposited film is formed by appropriately selecting the gas to be used, by using Si ₃ N ₄ , SiO ₂ , SiOF, Ta ₂ O.
₅ , insulating film such as TiO ₂ , TiN, Al ₂ O ₃ , AlN, MgF ₂ , a-Si, poly-Si, SiC, GaA
It is possible to efficiently form various deposited films such as a semiconductor film such as s and a metal film such as Al, W, Mo, Ti, and Ta.

Object to be processed 102 for manufacturing a structure
May be a semiconductor, a conductive material, or an electrically insulating material.

As the conductive object, Fe, Ni, C
r, Al, Mo, Au, Nb, Ta, V, Ti, Pt,
Examples include metals such as Pb or alloys thereof, such as brass and stainless steel.

Examples of the insulative object to be processed include SiO ₂ -based quartz, various glasses, Si ₃ N ₄ , NaCl, KCl, and Li.
Inorganic substances such as F, CaF ₂ , BaF ₂ , Al ₂ O ₃ , AlN and MgO, films of organic substances such as polyethylene, polyester, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide and polyimide, Examples include sheets.

The direction of the gas introducing means 105 is such that the gas is sufficiently supplied to the vicinity of the center after passing through the plasma region generated near the dielectric window 108 and then flows from the center to the periphery on the substrate surface. It is optimal to have a structure in which gas can be blown toward the body window 108.

Known gases can be used as the gas used when the thin film is formed on the substrate by the CVD method.

As a source gas containing Si atoms, which is introduced into the plasma processing chamber 101 through the processing gas introducing means 105 when forming a Si-based semiconductor thin film such as a-Si, poly-Si, or SiC, SiH is used. ₄ , Inorganic silanes such as Si ₂ H ₆ , tetraethylsilane (TES), tetramethylsilane (TMS), dimethylsilane (DM)
S), organic silanes such as dimethyldifluorosilane (DMDFS) and dimethyldichlorosilane (DMDCS), SiF ₄ , Si ₂ F ₆ , Si ₃ F ₈ , SiHF ₃ , SiH
₂ F ₂ , SiCl ₄ , Si ₂ Cl ₆ , SiHCl ₃ , SiH ₂
Examples thereof include halogenated silanes such as Cl ₂ , SiH ₃ Cl and SiCl ₂ F ₂ which are in a gas state at room temperature and normal pressure or which can be easily gasified. Also, in this case Si
The additive gas or carrier gas that may be mixed with the raw material gas and introduced is H ₂ , He, Ne, Ar, Kr, X.
e and Rn are mentioned.

Si₃N_Four, SiO₂Si compound-based thin
Via the processing gas introducing means 105 for forming a film
As a raw material containing Si atoms to be introduced, SiH_Four,
Si₂H₆Inorganic silanes such as tetraethoxysilane
(TEOS), tetramethoxysilane (TMOS), o
Kutamethylcyclotetrasilane (OMCTS), Dimethy
Ludifluorosilane (DMDFS), dimethyldichloro
Organic silanes such as silane (DMDCS), SiF_Four，
Si₂F₆, Si₃F₈, SiHF₃, SiH₂F₂, SiC
l_Four, Si₂Cl₆, SiHCl₃, SiH₂Cl₂, SiH
₃Cl, SiCl₂F ₂Halogenated silanes such as
Those that are in a gas state at normal temperature and pressure or can be easily gasified
There are things. In addition, in this case
As the raw material gas or the oxygen raw material gas, N₂, NH₃,
N₂H_Four, Hexamethyldisilazane (HMDS), O₂,
O₃, H₂O, NO, N₂O, NO₂And so on.

As a raw material containing metal atoms introduced through the processing gas introducing means 105 when forming a metal thin film of Al, W, Mo, Ti, Ta or the like, trimethylaluminum (TMAl), triethylaluminum ( TEAl), triisobutylaluminum (TIBA)
l), dimethyl aluminum hydride (DMAl
H), tungsten carbonyl (W (CO) ₆ ), molybdenum carbonyl (Mo (CO) ₆ ), trimethylgallium (TMGa), triethylgallium (TEGa), tetraisopropoxytitanium (TIPOTi), pentaethoxytantalum (PEOTa), etc. Organic metal, AlCl
Metal halides such as ₃ , WF ₆ , TiCl ₃ and TaCl ₅ can be cited. The additive gas or carrier gas that may be mixed with the Si source gas and introduced in this case includes H ₂ , He, Ne, Ar, Kr, Xe, and Rn.

Al ₂ O ₃ , AlN, Ta ₂ O ₅ , TiO ₂ ,
As a raw material containing a metal atom introduced through the processing gas introducing means 105 when forming a metal compound thin film such as TiN or WO ₃ , trimethylaluminum (TM) is used.
Al), triethyl aluminum (TEAl), triisobutyl aluminum (TIBAl), dimethyl aluminum hydride (DMAlH), tungsten carbonyl (W (CO) 6), molybdenum carbonyl (Mo).
(CO) ₆ ), trimethylgallium (TMGa), triethylgallium (TEGa), tetraisopropoxytitanium (TIPOTi), pentaethoxytantalum (PEO)
Organic metal such as Ta), AlCl ₃ , WF ₆ , TiC
Examples thereof include metal halides such as l ₃ and TaCl ₅ .
Further, in this case, as the oxygen source gas or the nitrogen source gas introduced at the same time, O ₂ , O ₃ , H ₂ O, NO, N ₂ O,
_{NO 2, N 2, NH 3} , N 2 H 4, etc. hexamethyldisilazane (HMDS) may be cited.

The etching gas introduced from the processing gas introduction port 105 for etching the surface of the object to be processed includes F ₂ , CF ₄ , CH ₂ F ₂ , C ₂ F ₆ , C ₃ F ₈ and C.
₄ F ₈ , CF ₂ Cl ₂ , SF ₆ , NF ₃ , Cl ₂ , CCl ₄ , C
Such as _{H 2 Cl 2, C 2 Cl} 6 and the like.

Processing gas introduction port 10 for ashing and removing organic components such as photoresist on the surface of the object to be processed
As the ashing gas introduced from No. 5, O ₂ , O ₃ ,
_{H 2 O, NO, N 2} O, NO 2, such as H ₂ and the like.

In the case of surface modification, by appropriately selecting the gas to be used, for example, Si, Al, Ti, Zn, Ta or the like is used as the target object or surface layer, and the target object or surface is treated. Oxidation treatment or nitridation treatment of the layer, and doping treatment of B, As, P or the like can be performed. Further, the film forming technique adopted can also be applied to the cleaning method. In that case, it can also be used for cleaning oxides, organic substances, heavy metals and the like.

As the oxidizing gas introduced through the processing gas introducing port 105 when the object to be treated is subjected to the oxidation surface treatment, O ₂ , O ₃ , H ₂ O, NO, N ₂ O, NO _{2 and the} like are used. Can be mentioned. In addition, as the nitriding gas introduced through the processing gas introduction port 115 when the object is subjected to the nitriding surface treatment, N ₂ , NH ₃ , N ₂ H ₄ , hexamethyldisilazane (H
MDS) and the like.

As a cleaning / ashing gas to be introduced from the gas introduction port 105 when the organic matter on the surface of the object to be processed is cleaned or when the organic components such as the photoresist on the surface of the object to be processed are removed by ashing,
₂ , O ₃ , H ₂ O, NO, N ₂ O, NO ₂ , H _{2 and the} like. Further, the cleaning gas introduced from the plasma generating gas introduction port when cleaning the inorganic substance on the surface of the object to be treated includes F ₂ , CF ₄ , CH ₂ F ₂ , C ₂ F ₆ ,
Such as _{C 4 F 8, CF 2 Cl} 2, SF 6, NF 3 and the like.

The plasma processing apparatus according to the present invention will be described below with reference to embodiments, but the present invention is not limited to the following embodiments.

(Embodiment 1) As Embodiment 1 of the present invention, an example in which a reflecting structure is not used and a quartz window is used will be described with reference to FIG. 101 is a substantially cylindrical plasma processing chamber, 1
Reference numeral 02 is a target object, 103 is a support for the target object 102, 1
Reference numeral 04 is a substrate temperature adjusting means, and 105 is a plasma processing chamber 10.
1, a plasma processing gas introduction means provided around 1
06 is an exhaust, 107 is a dielectric window for separating the plasma processing chamber 101 from the atmosphere side, 108 is a microwave for dielectric window 10
7 is a slotted endless circular waveguide for introduction into the plasma processing chamber 101 through the slot plate 1.
It is an assembly having 20.

The material of the dielectric window 107 is anhydrous synthetic quartz,
Thickness is about 16 mm, microwave frequency to be introduced 2.
The relative dielectric constant at 45 GHz is 3.8. The slotted endless annular waveguide 108 has an inner wall cross-sectional dimension of about 27.
mm × 96 mm, the center diameter of the waveguide is 202 mm
It is about (perimeter 4λg). The material of the slotted endless annular waveguide 108 is Al in order to suppress the propagation loss of microwaves. A slot for introducing microwaves into the plasma processing chamber 101 is formed on the H surface of the slotted endless annular waveguide 108. The shape of the slot is a rectangular shape having a length of about 40 mm and a width of about 4 mm, which are discontinuously formed on two straight lines and radially at intervals of about 1/2 of the guide wavelength. The in-tube wavelength depends on the frequency of the introduced microwave and the size of the cross section of the waveguide, but when the microwave having the frequency of about 2.45 GHz and the waveguide of the above size are used, It is about 159 mm. In the used endless annular waveguide 108 with a slot,
Eight sets of 16 slots are formed at intervals of about 45 degrees.
To the slotted endless annular waveguide 108, a 4E tuner, a directional coupler, an isolator, and a microwave power source (not shown) for generating microwaves having a frequency of about 2.45 GHz are sequentially connected.

Here, the microwave conversion interval from the lower surface of the endless annular waveguide 108 to the upper surface of the object support 103 is as follows: (1) The actual air gap from the lower surface of the endless annular waveguide 108 to the upper surface of the quartz window 107. Thickness about 1 mm × relative permittivity square root 1 = converted thickness about 1 mm (2) Quartz window 107 Actual thickness about 16 mm × relative permittivity square root 1.95 = converted thickness about 31.2 mm (3) From the bottom of the quartz window 107 Approximately 153 mm, which is the sum of the actual vacuum thickness of about 120.8 mm and the square root of relative permittivity 1 = converted thickness of about 120.8 mm up to the upper surface of the processing body support 103, that is, 2.45 G
The value is set to about 5/4 times the natural wavelength 122.4 mm of the microwave of Hz.

The plasma treatment is performed as follows. The inside of the plasma processing chamber 101 is evacuated via an exhaust system (not shown). Subsequently, the processing gas is introduced into the plasma processing chamber 101 at a predetermined flow rate through the gas introduction means 105 provided around the plasma processing chamber 101. Next, a conductance valve (not shown) provided in the exhaust system (not shown) is adjusted to maintain the inside of the plasma processing chamber 101 at a predetermined pressure. A desired power from a microwave power source (not shown) is passed through the endless annular waveguide 108 to the plasma processing chamber 101.
Supply in. Microwaves propagate toward the substrate until plasma with a cutoff density or higher is generated, but the microwave conversion distance between the lower surface of the endless annular waveguide 108 and the upper surface of the object support 103 is the natural wavelength of the microwave. Since it is an odd multiple of 4 minutes, microwave irradiation on the substrate is suppressed, and damage due to the irradiation is reduced. At this time, the processing gas introduced from the periphery is excited / excited by the generated high density plasma.
The surface of the object 102 to be processed, which is fixedly placed on the support 103, is processed by ionization / reaction and activation.

(Embodiment 2) An example in which a lower reflection surface is used as Embodiment 2 of the present invention will be described with reference to FIG. 201 is a cylindrical plasma processing chamber, 202 is an object to be processed, 203 is a support for the object 202 to be processed, 204 is a substrate temperature adjusting means, and 205 is a plasma processing gas introduction means provided around the plasma processing chamber 201. 206 is an exhaust gas, 207 is a dielectric window that separates the plasma processing chamber 201 from the atmosphere side, and 208 is a flat plate type endless annular waveguide with a slot for introducing microwaves into the plasma processing chamber 201 through the dielectric window 207. , 209 are bottom reflecting surfaces.

The material of the dielectric window 207 is anhydrous synthetic quartz,
The thickness is about 16 mm. The slotted endless annular waveguide 208 has a dimension of the inner wall cross section of about 27 mm × 96 mm, and the center diameter of the waveguide is about 202 mm (peripheral length about 4λg). The material of the slotted endless annular waveguide 208 is Al in order to suppress the propagation loss of microwaves. A slot 213 for introducing microwaves into the plasma processing chamber 201 is formed on the H surface of the endless annular waveguide 208 with slots, that is, on the conductive slot plate 220. The shape of the slot is about 40 mm long,
A rectangular shape having a width of about 4 mm is formed discontinuously on two straight lines and radially at intervals of 1/2 of the guide wavelength. The wavelength in the tube depends on the frequency of the microwave used and the size of the cross section of the waveguide. However, when the microwave having the frequency of about 2.45 GHz and the waveguide of the above size are used, the wavelength is about 1
It is 59 mm. In the used endless annular waveguide 208 with slots, eight sets of 16 slots are formed at intervals of about 45 degrees. The slotted endless annular waveguide 208 includes
4E tuner, directional coupler, isolator, 2.45
A microwave power source (not shown) having a frequency of GHz is sequentially connected. 221 is a plasma detection element.

Here, the distance from the lower reflecting surface 209 to the upper surface of the object support 203 is about 30.6 mm, that is,
Natural wavelength of microwave of 2.45 GHz 122.4 mm
Is set to a value of about 1/4.

The plasma treatment is performed as follows. The inside of the plasma processing chamber 201 is evacuated through an exhaust system (not shown). Then, the processing gas is introduced into the plasma processing chamber 201 at a predetermined flow rate through the gas introducing means 205 provided around the plasma processing chamber 201. Next, a conductance valve (not shown) provided in the exhaust system (not shown) is adjusted to maintain the inside of the plasma processing chamber 201 at a predetermined pressure. Desired power from a microwave power source (not shown) is passed through the endless annular waveguide 208 to the plasma processing chamber 201.
Supply in. Microwaves propagate toward the substrate until plasma with a cut-off density or higher is generated. However, since the distance from the lower reflection surface 209 to the upper surface of the target support 203 is about 1/4 of the natural wavelength of microwaves, Substrate irradiation of waves is suppressed and damage due to the irradiation is reduced. At this time, the processing gas introduced from the periphery is excited, ionized, and reacted by the generated high-density plasma to be activated, and the surface of the object 202 to be processed fixedly placed on the support 203 is processed.

(Embodiment 3) An example in which an eaves-shaped reflecting surface is used as Embodiment 3 of the present invention will be described with reference to FIG. Reference numeral 301 denotes a cylindrical plasma processing chamber, 302 denotes an object to be processed, 303 denotes a support for the object to be processed 302, 304 denotes substrate temperature adjusting means, and 305 denotes plasma processing gas introducing means provided around the plasma processing chamber 301. Reference numeral 306 is an exhaust gas, 307 is a dielectric window that separates the plasma processing chamber 301 from the atmosphere side, and 308 is a flat plate type endless annular waveguide with a slot for introducing microwaves into the plasma processing chamber 301 through the dielectric window 307. , 309 are eaves-shaped reflecting surfaces.

The material of the dielectric window 307 is anhydrous synthetic quartz,
The thickness is about 16 mm. The slotted endless annular waveguide 308 has a dimension of the inner wall cross section of about 27 mm × 96 mm, and the center diameter of the waveguide is about 302 mm (peripheral length about 4λg). The material of the slotted endless annular waveguide 308 is Al in order to suppress the propagation loss of microwaves. A slot 313 for introducing microwaves into the plasma processing chamber 301 is formed on the H surface of the endless annular waveguide with slot 308, that is, on the conductive slot plate 320. The shape of the slot is a rectangular shape having a length of about 40 mm and a width of about 4 mm, which are discontinuously formed on two straight lines and radially at intervals of about 1/2 of the guide wavelength. The in-tube wavelength depends on the frequency of the microwave used and the size of the cross section of the waveguide, but when the microwave of the frequency of about 2.45 GHz and the waveguide of the above size are used, 1
It is 59 mm. In the used endless annular waveguide 308 with slots, eight sets of 16 slots are formed at intervals of about 45 degrees. In the slotted endless annular waveguide 308,
4E tuner, directional coupler, isolator, 2.45
A microwave power source (not shown) having a frequency of GHz is sequentially connected. Reference numeral 321 is a plasma detection element.

Here, the distance from the eaves-shaped reflecting surface 309 to the upper surface of the object support 303 is about 30.6 mm, that is,
Natural wavelength of microwave of 2.45 GHz 122.4 mm
Is set to a value of about 1/4.

The plasma treatment is performed as follows. The inside of the plasma processing chamber 301 is evacuated through an exhaust system (not shown). Then, the processing gas is introduced into the plasma processing chamber 301 at a predetermined flow rate through the gas introduction unit 305 provided around the plasma processing chamber 301. Next, a conductance valve (not shown) provided in the exhaust system (not shown) is adjusted to maintain the inside of the plasma processing chamber 301 at a predetermined pressure. Desired power from a microwave power source (not shown) is passed through the endless annular waveguide 308 to the plasma processing chamber 301.
Supply in. The microwave propagates toward the substrate until plasma with a cutoff density or higher is generated, but the distance from the eaves-shaped reflection surface 309 to the upper surface of the support body 303 to be processed is set to about 1/4 of the natural wavelength of the microwave. Therefore, the microwave irradiation of the substrate is suppressed, and the damage caused by the irradiation is reduced. At this time, the processing gas introduced from the periphery is excited, ionized, and reacted by the generated high-density plasma to be activated, and the object to be processed 30 fixedly placed on the support 303.
Treat surface 2.

(Embodiment 4) An example in which a groove-shaped reflecting surface is used as Embodiment 4 of the present invention will be described with reference to FIG. Reference numeral 401 is a cylindrical plasma processing chamber, 402 is an object to be processed, 403 is a support for the object to be processed 402, 404 is a substrate temperature adjusting means, and 405 is a plasma processing gas introducing means provided around the plasma processing chamber 401. 406 is an exhaust gas, 407 is a dielectric window that separates the plasma processing chamber 401 from the atmosphere side, and 408 is a flat plate type endless annular waveguide with a slot for introducing microwaves into the plasma processing chamber 401 through the dielectric window 407. , 409 are groove-shaped reflecting surfaces.

The material of the dielectric window 407 is anhydrous synthetic quartz,
The thickness is about 16 mm. The slotted endless annular waveguide 408 has a dimension of the inner wall cross section of about 27 mm × 96 mm, and the center diameter of the waveguide is about 402 mm (peripheral length about 4λg). The material of the slotted endless annular waveguide 408 is all Al in order to suppress the propagation loss of microwaves. A slot 413 for introducing microwaves into the plasma processing chamber 401 is formed on the H surface of the slotted endless annular waveguide 408, that is, on the conductive slot plate 420. The shape of the slot is a rectangular shape having a length of about 40 mm and a width of about 4 mm, which are discontinuously formed on two straight lines and radially at intervals of about 1/2 of the guide wavelength. The in-tube wavelength depends on the frequency of the microwave used and the size of the cross section of the waveguide, but when the microwave of the frequency of about 2.45 GHz and the waveguide of the above size are used, 1
It is 59 mm. In the used endless annular waveguide 408 with slots, eight sets of 16 slots are formed at intervals of about 45 degrees. In the slotted endless annular waveguide 408,
4E tuner, directional coupler, isolator, about 2.4
A microwave power source (not shown) having a frequency of 5 GHz is sequentially connected. 421 is a plasma detection element.

Here, the distance from the groove-shaped reflecting surface 409 to the upper surface of the object support 403 is about 30.6 mm, that is,
Natural wavelength of microwave of 2.45 GHz 122.4 mm
Is set to a value of about 1/4.

The plasma treatment is performed as follows. The inside of the plasma processing chamber 401 is evacuated via an exhaust system (not shown). Subsequently, the processing gas is introduced into the plasma processing chamber 401 at a predetermined flow rate through the gas introduction unit 405 provided around the plasma processing chamber 401. Next, a conductance valve (not shown) provided in the exhaust system (not shown) is adjusted to maintain the inside of the plasma processing chamber 401 at a predetermined pressure. A desired power from a microwave power source (not shown) is supplied to the plasma processing chamber 401 via the endless annular waveguide 408.
Supply in. Microwaves propagate toward the substrate until plasma with a cut-off density or higher is generated, but the distance from the groove-shaped reflecting surface 409 to the upper surface of the support body 403 to be processed is set to about 1/4 of the natural wavelength of microwaves. Therefore, the microwave irradiation of the substrate is suppressed, and the damage caused by the irradiation is reduced. At this time, the processing gas introduced from the periphery is excited, ionized, and reacted by the generated high-density plasma to be activated, and the object to be processed 40 fixedly placed on the support 403.
Treat surface 2.

(Examples of Plasma Treatment) Hereinafter, the plasma treatment performed by using the above embodiment will be specifically described, but the surface treatment method of the present invention is not limited to these examples.

(Processing Example 1) The microwave plasma processing apparatus shown in FIG. 1 was used to ash the photoresist.

As the object to be processed 102, a silicon (Si) substrate (φ about 300 mm) was used immediately after the interlayer SiO ₂ film was etched to form a via hole. First, S
After the i substrate 102 is placed on the object support 103,
The heater 104 was used to heat up to about 250 ° C., and the inside of the plasma processing chamber 101 was evacuated through an exhaust system (not shown) to reduce the pressure to about 1.33 × 10 ⁻² Pa.

Oxygen gas is supplied through the plasma processing gas inlet 105 at a flow rate of about 2 slm to the plasma processing chamber 101.
Introduced in. Then, a conductance valve (not shown) provided in the exhaust system (not shown) is adjusted to adjust the processing chamber 10
The inside of 1 was maintained at about 1.995 × 10 ² Pa.

Inside the plasma processing chamber 101, 2.45 GH
About 2.5 kW of electric power was supplied from the microwave power source of z through the endless annular waveguide 108 with slots. In this way, plasma was generated in the plasma processing chamber 101. At this time, the plasma detection element 121 was used to perform processing while monitoring the plasma state, and the microwave supply was stopped when the emission of the wavelength due to carbon, which is a constituent atom of the photoresist, weakened to some extent. During the processing, the oxygen gas introduced through the plasma processing gas introduction port 105 is excited, decomposed, and reacted in the plasma processing chamber 101 to become oxygen atoms, which moves toward the silicon substrate 102 and moves on the substrate 102. The resist was oxidized and vaporized and removed. After the ashing, the gate dielectric breakdown evaluation, the ashing speed and the charge density on the substrate surface were evaluated.

The uniformity of the obtained ashing rate is ±
It was extremely large at about 3.7% (about 6.7 μm / min), the surface charge density was about 0.4 × 10 ¹¹ cm ^−2, which was a sufficiently low value, and no gate dielectric breakdown was observed.

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

As the object 202 to be processed, a silicon (Si) substrate (about 12 inches in diameter) was used immediately after the interlayer SiO ₂ film was etched to form a via hole. First,
After the Si substrate 202 is placed on the target support 203, it is heated to about 250 ° C. by using the heater 204, and the inside of the plasma processing chamber 201 is evacuated through an exhaust system (not shown). The pressure was reduced to about 10 ⁻³ Pa. 2 sl of oxygen gas is supplied through the plasma processing gas inlet 205.
It was introduced into the plasma processing chamber 201 at a flow rate of about m.

Then, the conductance valve (not shown) provided in the exhaust system (not shown) is adjusted to adjust the process chamber 201.
The inside was maintained at about 2.66 × 10 ² Pa. In the plasma processing chamber 201, about 2.5 kW of electric power is supplied from a 2.45 GHz microwave power source to the slotted endless annular waveguide 20.
Feed via 8 In this way, plasma was generated in the plasma processing chamber 201. At this time, the plasma detection element 221 was used to perform processing while monitoring the plasma state, and the microwave supply was stopped when the emission of the wavelength due to carbon, which is a constituent atom of the photoresist, weakened to some extent. During processing, gas inlet 20 for plasma processing
Oxygen gas introduced through the plasma processing chamber 201
It was excited, decomposed, and reacted inside to become oxygen atoms, moved to the silicon substrate 202, oxidized the photoresist on the substrate 202, and vaporized and removed. After ashing, gate insulation evaluation, ashing speed and substrate surface charge density were evaluated.

The obtained ashing rate uniformity was ± 4.
It was extremely large at about 8% (about 8.6 μm / min), the surface charge density was about 1.2 × 10 ¹¹ cm ^-2, which was a sufficiently low value, and no gate dielectric breakdown was observed.

(Processing 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 object 102 to be processed, a p-type single crystal silicon substrate (plane orientation <100>, resistivity of about 300 mm) with an interlayer SiO ₂ film having an Al wiring pattern (line and space of about 0.5 μm) formed thereon was used. 10 Ωcm) was used. First, after the silicon substrate 102 is placed on the object support 103, the inside of the plasma processing chamber 101 is evacuated through an exhaust system (not shown) to obtain 1.33 × 10 ⁻⁵ P.
The pressure was reduced to a value of about a. Then, the heater 104 was energized to heat the silicon substrate 102 to about 300 ° C., and the substrate was kept at this temperature. Gas inlet for plasma processing 1
Nitrogen gas at a flow rate of about 600 sccm and monosilane gas at a flow rate of 200 sccm via Process 05.
It was introduced in 01. Then, a conductance valve (not shown) provided in the exhaust system (not shown) was adjusted to maintain the inside of the processing chamber 101 at about 2.66 Pa.

Next, a power of about 3.0 kW was supplied from a 2.45 GHz microwave power source (not shown) through the endless annular waveguide 108 with slots. In this way
Plasma was generated in the plasma processing chamber 101. At this time, the plasma detection element 121 was used to perform processing while monitoring the plasma state. During the processing, the nitrogen gas introduced through the plasma processing gas introduction port 105 is excited and decomposed in the plasma processing chamber 101 to become nitrogen atoms, which moves toward the silicon substrate 102, reacts with the monosilane gas, and reacts with silicon nitride. The film is 1.0 on the silicon substrate 102.
It was formed with a thickness of about μm. After film formation, evaluation of gate dielectric breakdown, film formation speed, film quality such as stress was evaluated. As for the stress, the change in the amount of warp of the substrate before and after the film formation is measured by laser interferometer
It was measured and obtained with o (trade name).

The uniformity of the film formation rate of the obtained silicon nitride film was extremely large, about ± 2.6% (about 560 nm / min), and the film quality was about 0.8 × 10 ⁹ dyne · cm ⁻² (compressed). ), A leakage current of about 1.2 × 10 ⁻¹⁰ A · cm ⁻² and a dielectric strength of about 10.3 MV / cm were confirmed to be extremely high quality films, and no gate dielectric breakdown was observed.

(Processing Example 4) Using the microwave plasma processing apparatus shown in FIG. 2, a plastic lens antireflection silicon oxide film and a silicon nitride film were formed.

The object 202 to be processed has a diameter of about 50 mm.
A plastic convex lens was used. After the lens 202 is placed on the object support base 203, the inside of the plasma processing chamber 201 is evacuated through an exhaust system (not shown) to 1.33.
The pressure was reduced to a value of about 10 ⁻⁵ Pa. About 150 sccm of nitrogen gas is supplied through the plasma processing gas inlet 205.
And the monosilane gas was introduced into the processing chamber 201 at a flow rate of about 70 sccm. Then, a conductance valve (not shown) provided in the exhaust system (not shown) was adjusted to maintain the inside of the processing chamber 201 at about 6.55 × 10 ^-1 Pa.

Next, a power of about 3.0 kW was supplied from a 2.45 GHz microwave power source (not shown) into the plasma processing chamber 201 through the endless annular waveguide 203 with slots. In this way, plasma was generated in the plasma processing chamber 201. At this time, the nitrogen 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 nitrogen atoms, moves toward the lens 202, and reacts with the monosilane gas. Then, a silicon nitride film was formed on the lens 202 with a thickness of about 20 nm.

Next, the processing chamber 201 is supplied with oxygen gas at a flow rate of about 200 sccm and monosilane gas at a flow rate of about 100 sccm through the plasma processing gas introduction port 205.
Introduced in. Then, the conductance valve (not shown) provided in the exhaust system (not shown) is adjusted to adjust the process chamber 20.
The inside of 1 was maintained at about 2.66 × 10 ⁻¹ Pa. Then,
2.0 from a 2.45 GHz microwave power source (not shown)
Electric power of kW was supplied into the plasma generation chamber 201 through the endless annular waveguide 208 with a slot. In this way, 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, and the glass substrate 20.
It moved in the direction 2 and reacted with monosilane gas to form a silicon oxide film on the glass substrate 202 with a thickness of about 85 nm. After the film formation, the gate dielectric breakdown evaluation, the film formation speed, and the reflection characteristics were evaluated.

The film-forming rate uniformity of the obtained silicon nitride film and silicon oxide film is about ± 2.7% (about 37%).
0 nm / min), about ± 2.8% (about 410 nm / m
in), and the film quality was confirmed to have extremely good optical characteristics with a reflectance of about 0.17% in the vicinity of 500 nm, and no gate dielectric breakdown was observed.

(Processing Example 5) The microwave plasma processing apparatus shown in FIG. 1 was used to form a silicon oxide film for semiconductor element interlayer insulation.

As the object to be processed 102, a p-type single crystal silicon substrate (plane orientation <100>, resistivity about 10 Ωcm) of about φ300 mm having an Al pattern (line and space of about 0.5 μm) formed on the uppermost portion is used. used. First, the silicon substrate 102 was placed on the object support 103. Plasma processing chamber 10 via an exhaust system (not shown)
The inside of 1 was evacuated and the pressure was reduced to a value of about 1.33 × 10 ⁻⁵ Pa. Subsequently, the heater 104 was energized to heat the silicon substrate 102 to 300 ° C. and maintain the substrate at this temperature. Oxygen gas was introduced into the processing chamber 101 at a flow rate of about 400 sccm and monosilane gas at a flow rate of about 200 sccm through the plasma processing gas introduction port 105.

Then, a conductance valve (not shown) provided in the exhaust system (not shown) was adjusted to maintain the inside of the plasma processing chamber 101 at about 2.66 Pa. Then, about 300 W of electric power is applied to the substrate support 102 through a high frequency applying means of about 2 MHz, and 2.45 GH is applied.
About 2.5 kW of electric power from the microwave power source of z is supplied to the plasma processing chamber 10 through the endless annular waveguide 103 with slots.
It was supplied within 1.

In this way, plasma was generated in the plasma processing chamber 101. Gas inlet for plasma processing 1
Oxygen gas introduced through 05 is the plasma processing chamber 10
The silicon substrate 1 is excited and decomposed in 1 to become active species.
It moved in the direction of 02 and reacted with monosilane gas to form a silicon oxide film on the silicon substrate 102 with a thickness of about 0.8 μm. At this time, the ion species are accelerated by the RF bias and enter the substrate to scrape the film on the pattern and improve the flatness. After processing, film formation speed, uniformity, withstand voltage,
And the step coverage. The step coverage is Al
The cross section of the silicon oxide film formed on the wiring pattern was observed by a scanning electron microscope (SEM), and the voids were observed to evaluate.

The film formation rate uniformity of the obtained silicon oxide film was as good as about ± 2.8% (about 310 nm / min),
It was confirmed that the film quality was a void-free, high-quality film with a withstand voltage of about 9.1 MV / cm, and no gate dielectric breakdown was observed.

(Processing Example 6) The microwave plasma processing apparatus shown in FIG. 2 was used to etch the SiO ₂ film between semiconductor elements.

As the object 202 to be processed, about 1 μm is formed on the Al pattern (line and space is about 0.35 μm).
m p-type single crystal silicon substrate of about φ300mm interlayer SiO ₂ film is formed in thickness (face orientation <100>, resistivity 1
0 Ωcm) was used. First, the silicon substrate 202
After being installed on the object support base 203, the inside of the etching chamber 201 is evacuated through an exhaust system (not shown).
The pressure was reduced to a value of about 33 × 10 ⁻⁵ Pa. About 80 scc of C ₄ F ₈ through the plasma processing gas inlet 205
m and Ar were introduced into the plasma processing chamber 201 at a flow rate of about 120 sccm and O ₂ at a flow rate of about 40 sccm. Then,
The conductance valve (not shown) provided in the exhaust system (not shown) is adjusted to adjust the inside of the plasma processing chamber 201 to 6.6.
The pressure was kept at 5 × 10 ⁻¹ Pa.

Then, an electric power of about 280 W is applied to the substrate support 202 through a high frequency applying means of about 2 MHz, and an electric power of about 3.0 is applied from a microwave power source of 2.45 GHz.
Electric power of kW was supplied into the plasma processing chamber 201 through the endless annular waveguide 203 with a slot. In this way, plasma was generated in the plasma processing chamber 201.
At this time, the plasma detection element 221 was used to perform processing while monitoring the plasma state, detect changes in light emission due to constituent atoms of silicon oxide, and stop the supply of microwaves. The C ₄ F ₈ gas introduced through the plasma processing gas introduction port 205 is excited and decomposed in the plasma processing chamber 201 to become active species, which moves toward the silicon substrate 202 and is accelerated by self-bias. The inter-layer SiO ₂ film was etched by. The cooler 207 with an electrostatic chuck increased the substrate temperature to only about 30 ° C. After etching, the gate dielectric breakdown evaluation, etching rate, selection ratio, and etching shape were evaluated. The etching shape was evaluated by observing the cross section of the etched silicon oxide film with a scanning electron microscope (SEM).

Uniformity of etching rate and selectivity to polysilicon are about ± 2.4% (about 720 nm / min), 20
It was confirmed that the etching shape was almost vertical, the microloading effect was small, and no gate dielectric breakdown was observed.

(Processing Example 7) The microwave plasma processing apparatus shown in FIG. 1 was used to etch the polysilicon film between semiconductor element gate electrodes.

As the object to be processed 102, a policy is provided at the top.
Φ300mm p-type single crystal film with recon film
Recon substrate (plane orientation <100>, resistivity about 10 Ωcm)
It was used. First, the silicon substrate 102 is supported on an object to be processed.
After installation on the stand 103, the exhaust system (not shown)
The inside of the plasma processing chamber 101 was evacuated to 1.33 × 10 ^-Five
The pressure was reduced to a value of about Pa. Gas introduction for plasma processing
CF through mouth 105 _FourAbout 300 sccm gas, oxygen
At a flow rate of about 20 sccm into the plasma processing chamber 101.
I entered.

Then, a conductance valve (not shown) provided in the exhaust system (not shown) was adjusted to maintain the inside of the plasma processing chamber 101 at a pressure of about 2.66 × 10 ^-1 Pa. Next, about 300 W of high-frequency power from a high-frequency power supply of 2 MHz (not shown) is applied to the substrate support 103, and about 2.0 k from the microwave power supply of 2.45 GHz.
Power of W was supplied into the plasma processing chamber 101 through the endless annular waveguide 103 with slots.

In this way, plasma was generated in the plasma processing chamber 101. At this time, the plasma detection element 12
1 was used to perform processing while monitoring the plasma state, detect changes in light emission due to silicon, and stop the supply of microwaves. The CF ₄ gas and oxygen introduced through the plasma processing gas inlet 105 are used in the plasma processing chamber 1
In 01, the polysilicon film was excited and decomposed to become active species, moved to the direction of the silicon substrate 102, and the polysilicon film was etched by the ions accelerated by self-bias. Due to the cooler 104 with an electrostatic chuck, the substrate temperature rose only up to about 30 ° C. After etching, the gate dielectric breakdown evaluation, etching rate, selection ratio, and etching shape were evaluated. The etching shape is the scanning electron microscope (SEM) of the cross section of the etched polysilicon film.
Was observed and evaluated.

The etching rate uniformity and the SiO ₂ selection ratio are about ± 2.9% (about 820 nm / min),
22, the etching shape was vertical, the microloading effect was small, and no gate dielectric breakdown was observed.

[0100]

As described above, according to the present invention,
The distance between the surface of the object to be processed and the surface of the microwave waveguide on the side of the plasma processing chamber is set to an odd multiple of a quarter of the microwave conversion wavelength, and the microwave introduced into the plasma processing chamber and the object to be processed are processed. Since the microwaves reflected on the surface weaken each other, it is possible to reduce the irradiation of the microwave on the surface of the object to be treated and suppress the damage due to the irradiation even in the initial stage of the discharge.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a plasma processing apparatus of the present invention.

FIG. 2 is a schematic view showing an example using a lower reflecting surface which is one embodiment of the present invention.

FIG. 3 is a schematic diagram showing an example using an eaves-shaped reflecting surface which is an embodiment of the present invention.

FIG. 4 is a schematic view showing an example using a groove-shaped reflecting surface which is an embodiment of the present invention.

FIG. 5 is a schematic diagram showing a conventional example.

[Explanation of symbols]

101, 201, 301, 401, 901 Plasma processing chambers 102, 202, 302, 402, 902 Object 103, 203, 303, 403, 903 Object support 104, 204, 304, 404, 904 Substrate temperature adjustment Means 105, 205, 305, 405, 905 Processing gas introduction means 106, 206, 306, 406, 906 Exhaust gas 107, 207, 307, 407, 907 Dielectric window 108, 208, 308, 408, 908 Slotted endless Annular waveguide 109, 209, 309, 409 Reflecting means 111, 911 E branch 112, 912 In-tube standing wave 113, 913 Slot 114, 914 Surface wave 115, 915 Surface standing wave 116, 916 Surface plasma 117, 917 Bulk Plasma 120, 220, 320, 420 slots 121,221,321,421 plasma detection element

Continued front page    F-term (reference) 4K030 FA02 JA03 KA15 KA39 KA41                       KA46                 5F004 AA06 BA20 BB14 BB18 BB22                       BB25 BC08 BD01 BD04 CB02                       CB16 DA00 DA01 DA23 DA26                       DB02 DB03 DB26 EB02 EB03                 5F045 AA09 AB03 AB04 AB06 AB10                       AB32 AB33 AB40 AC01 AC02                       AC08 AC09 AC11 AC12 AC16                       AC17 AE13 AE15 AE17 AE19                       AE21 AE23 BB16 CB04 CB05                       DP03 DQ10 EB02 EE20 EH03                       EH19 GB08

Claims (14)

[Claims] 1. A plasma processing apparatus for performing plasma processing by introducing microwaves into a plasma processing chamber through a microwave supplier to generate plasma in the plasma processing chamber, the surface of an object to be plasma-treated. And a microwave conversion distance between the microwave supply device and the microwave supply device is an odd multiple of a quarter of a natural wavelength. 2. A dielectric window is provided between the microwave supplier and the plasma processing chamber, and a value of a microwave-converted thickness of the dielectric window corresponds to a frequency of the introduced microwave. 2. The plasma processing apparatus according to claim 1, wherein the value is obtained by multiplying the actual thickness by the square root of the relative permittivity of the material of the dielectric window. 3. The plasma processing apparatus according to claim 1, wherein the microwave supplier is a plate-shaped multi-slot antenna using an endless annular waveguide. 4. A plasma processing apparatus which introduces microwaves into a plasma processing chamber through a microwave supplier to generate plasma in the plasma processing chamber, wherein the surface of the object to be plasma-treated is converted into microwaves. A plasma processing apparatus comprising microwave reflecting means for reflecting the microwave reflected on the surface of the object to be processed, at a position that is an odd multiple of a quarter of the natural wavelength of the microwave at a distance. 5. The plasma processing apparatus according to claim 4, wherein the microwave supplier is a flat plate-shaped multi-slot antenna using an endless annular waveguide. 6. The plasma processing apparatus according to claim 4, wherein the microwave reflecting means is a reflecting surface having an area of 5% or more of a cross-sectional area of the plasma processing chamber. 7. The microwave reflecting means has an eaves-like structure protruding inward from a wall surface of the plasma processing chamber having an area of 5% or more of a cross-sectional area of the plasma processing chamber. The plasma processing apparatus of 4 or 5. 8. The microwave reflecting means has a groove-like structure that is inserted into a wall surface of the plasma processing chamber and has an area of 5% or more of a cross-sectional area of the plasma processing chamber. 5. The plasma processing apparatus according to item 5. 9. The microwave reflecting means has a mesh-like structure projecting into the plasma processing chamber from a wall surface of the plasma processing chamber having an area of 5% or more of a cross-sectional area of the plasma processing chamber. The plasma processing apparatus according to claim 4 or 5. 10. The plasma processing apparatus according to claim 9, wherein the mesh hole diameter of the mesh structure is ⅛ or less of a natural wavelength of microwave. 11. A plasma processing apparatus for introducing a high frequency into the plasma processing chamber through a high frequency supply device to generate plasma in the plasma processing chamber, wherein a high frequency emission slot is formed in the high frequency supply device. A plasma processing apparatus having a plasma detection element for detecting plasma. 12. The plasma processing apparatus according to claim 11, wherein the slot is provided in a slot plate arranged at a position facing the surface to be processed of the object to be processed. 13. The plasma processing apparatus according to claim 11, wherein the plasma detection element is connected to a control device that stops the supply of microwaves based on the detection result of the plasma detection element. 14. A method of manufacturing a structure, comprising a step of plasma-treating a surface of a substrate on which the structure is formed, wherein the plasma treatment is performed by using the plasma treatment apparatus according to any one of claims 1 to 13. The manufacturing method of the structure characterized by performing.