JP2001043997A - Plasma processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the density of plasma by reducing the thickness of a microwave-transmissive dielectric window. SOLUTION: This plasma processing device has an evacuatable container 1, a gas feeding means 7 for feeding a gas into the container, a microwave feeder 3 for feeding microwave for generating plasma in the container, and a dielectric window 4 for transmitting the microwave. In this case, a microwave- transmissive sealing body is formed on each of slots 33 of the microwave feeder 3, and the dielectric window 4 is formed into a sheet-like shape having a thickness <=5 mm common to the plural slots.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a plasma processing apparatus for performing plasma processing on an object to be processed using microwaves.

[0002]

2. Description of the Related Art As a plasma processing apparatus using a microwave as an excitation energy source for generating plasma, a plasma polymerization apparatus, a CVD apparatus, a surface reforming apparatus, an etching apparatus, an ashing apparatus, a cleaning apparatus and the like are known. .

[0003] CVD using such a so-called microwave plasma processing apparatus is performed, for example, as follows. That is, a gas is introduced into a processing chamber of a microwave plasma CVD apparatus, and simultaneously, microwave energy is applied to generate plasma to excite and / or decompose the gas to deposit a film on an object to be processed disposed in the processing chamber. To form Then, surface modification such as plasma polymerization, oxidation, nitridation, and fluorination of an organic substance can be performed in the same manner.

[0004] Etching of an object 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 simultaneously, microwave energy is applied to excite and / or decompose the etchant gas to generate plasma in the processing chamber. The surface of the processed object is etched.

[0005] Further, ashing processing of an object 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 at the same time, microwave energy is applied to excite and / or decompose the ashing gas to generate plasma in the processing chamber. Ashing the surface of the object to be processed, ie, the photoresist. In the same manner as ashing, cleaning for removing unnecessary substances attached to the surface of the object to be processed can be performed.

[0006] As the microwave plasma processing apparatus described above, there is a type which is divided into a plasma generation chamber and a processing chamber.

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 advantages such as high ionization efficiency, excitation efficiency and decomposition efficiency of the gas, relatively easy formation of high-density plasma, and high-speed processing at low temperature and high speed. In addition, since the microwave has a 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 a highly clean plasma processing can be performed.

FIG. 12 shows a microwave plasma processing apparatus of the type described in JP-A-11-40397.

1 is a container whose inside can be evacuated, 2 is a support for the object W to be processed, 3 is a microwave supply device for supplying a microwave for generating plasma in the container, and 4 is a microwave transmitting device. Reference numeral 7 denotes a gas supply means for supplying gas into the container, 7a denotes a gas discharge port, 13 denotes a microwave inlet, and 33 denotes a slot.

[0010] The ceiling wall of the container adjacent to the plurality of slots 33 for radiating microwaves comprises a dielectric window 4.

The dielectric window transmits a microwave and separates an atmosphere capable of reducing pressure from the inside of the container from an atmospheric pressure outside the container, so that the dielectric window has a mechanical strength enough to withstand a difference between these pressures. And is attached to an adjacent container outer wall with an O-ring or the like.

FIG. 13 shows a cross section of a plasma processing apparatus based on this method. The thick dielectric window 4 is
Is sandwiched and fixed by the upper side wall of the microwave supply device 3 and the lower portion of the microwave supply device 3. FIG. 14 shows the state of microwave propagation, radiation and generation of plasma.

[0013]

As the object to be processed W has a large area, for example, a wafer having a diameter of about 300 mm, the size of the container also increases. When the above dielectric window is made of a disk having a diameter of more than 300 mm, the thickness becomes 12 m.
m to 14 mm. In addition, the problem of deformation and breakage due to heat generation becomes significant.

[0014] Because the electric field strength of the microwaves emitted into the container through the dielectric window decreases as the thickness of the dielectric window increases, the increase in the thickness of the dielectric window increases the intensity of the plasma. This is a factor that hinders further densification.

[0015]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a plasma processing method capable of suppressing the increase in the thickness of a dielectric window and increasing the density of plasma while ensuring mechanical strength sufficient to withstand a pressure difference between the inside and outside of a container. It is to provide a device.

According to the present invention, there is provided a container whose inside can be evacuated, gas supply means for supplying a gas into the container, a microwave supply device for supplying a microwave for generating plasma in the container, A dielectric window for transmitting a wave, and a plasma processing apparatus for processing an object to be processed using the plasma, wherein a plurality of slots for radiating microwaves provided in the microwave supply device are provided. Each is provided with a microwave transparent sealing body, and the dielectric window is formed into a sheet having a thickness of 5 mm or less common to the plurality of slots.

[0017]

FIG. 1 shows a plasma processing apparatus according to a preferred embodiment of the present invention.

This plasma processing apparatus comprises a container 1 capable of evacuating the inside, and gas supply means 7 for supplying gas into the container 1.
And a microwave supplier 3 for supplying microwaves for generating plasma in the container 1 and a dielectric window 4 for transmitting microwaves.

Each of the plurality of slots 33 provided in the microwave supply device 3 for radiating microwaves is provided with a microwave-transmissive sealing member 14, and the dielectric window 4 is provided with a plurality of dielectric windows 4. It is a sheet-like dielectric having a thickness of 5 mm or less common to the slots.

The object to be processed W is supported on a support 2,
It is arranged in the container 1. If necessary, as shown in FIG. 1, the support 2 may be provided with a temperature controller 12 for adjusting the temperature of the workpiece W. The temperature controller 12 can be a heater for heating the object to be processed W or a cooler for cooling the object to be processed W.

The exhaust system 8 includes a vacuum pump, a valve, and the like, and operates so as to exhaust the inside of the container 1 and maintain the inside of the container 1 at a predetermined pressure.

The gas supply system 6 comprises a gas cylinder, a valve, a flow controller and the like.

The microwave supplier 3 of the present embodiment has a conductive flat plate 23 having a plurality of slots 33 as shown in FIG. Then, a conductive member having a concave portion constituting the endless annular waveguide 13 and a conductive flat plate 23 are assembled.

Then, the sealing member 14 is placed in the concave portion serving as the waveguide.
Is arranged. The sheet-like dielectric window 4 is attached to the outside of the annular waveguide 13, that is, below the conductive flat plate 23 by welding or the like, and covers the slot 33 from below.

The waveguide 13 is connected to the microwave waveguide 5, and a microwave is introduced from a microwave power supply (not shown) through the waveguide 5. Since the waveguide 13 is normally in communication with the atmosphere, the inside is at atmospheric pressure. Meanwhile, container 1
Since the inside is usually evacuated and reduced in pressure, a differential pressure is applied between the dielectric window 4 and the sealing body 14. Since the sealing body 14 is disposed in the waveguide 13, a differential pressure is applied to each of the slots 33, but since the size thereof is in accordance with the opening area of the slot 33, the mechanical strength is high. Is relatively low, it can withstand this differential pressure sufficiently. Thus, the function as the wall of the container is dispersed in the sealing body.

Further, since not all of the top wall of the container is made of a sealing body, the characteristics required for the sealing body are loose.

Since the sealing member 14 maintains the pressure difference, the mechanical strength required for the dielectric window 4 is low, and the selection range of the materials and dimensions for the dielectric window can be expanded. it can.

The plasma processing is performed as follows. The inside of the container 1 is evacuated through the evacuation system 8. Subsequently, a processing gas is introduced into the plasma processing chamber from the gas supply means 7 at a predetermined flow rate. Next, the conductance control valve provided in the exhaust system 8 is adjusted to maintain the plasma processing chamber at a predetermined pressure. A desired power is supplied from the microwave power supply to the plasma processing chamber through the endless annular waveguide 13. As shown in FIG. 3, the microwave introduced into the endless annular waveguide 13 is split right and left by the E-branch 25 and propagates with a longer guide wavelength than free space. 1 of tube wavelength
The high-density plasma P1 is generated by the microwaves transmitted through the dielectric window 4 through the slots 33 provided at every 1/2 or 1/4 and introduced into the plasma processing chamber. In this state, the microwave incident on the plasma P1
1, and propagates at the interface between the dielectric window 4 and the plasma P1 as a surface wave SW. Adjacent slot 33
Surface waves SW introduced from each other interfere with each other, and the surface waves S
An antinode of the electric field is formed every half of the wavelength of W. A high-density plasma P2 is generated by the anti-node electric field due to the surface wave interference. Plasma is generated when the dielectric window 4 is thin. The processing gas introduced from the periphery of the vessel 1 is excited, ionized, and activated by the generated high-density plasma P2 to activate and process the surface of the processing target W placed on the support 2.

In particular, since the thickness can be reduced, microwave radiation characteristics are improved and high-density plasma is easily generated. A comparison between FIG. 3 and FIG. 14 shows that the electric field weakness is increased.

FIGS. 4 to 6 are schematic views showing structures near the sealing body and the dielectric window used in the present invention. FIG. 4 shows a structure in which the microwave transparent sealing body 14 is filled in the slot 33 and hermetically sealed by a hermetic sealing material 24 such as an O-ring.

FIG. 5 shows a structure in which the convex portion of the microwave-transmissive sealing body 14 that is convex downward is fitted in the slot 33 and the flange-shaped portion is arranged in the waveguide 13.

FIG. 5 shows a structure in which a conductive member 34 having an opening area larger than the slot 33 is disposed below the slot 33, and the opening is filled with the microwave transparent sealing member 14. . The sealing body 14 is fixed by sandwiching a flange-like portion of the sealing body 14 between the slotted flat plate and the conductive member 34.

The sealing member 14 can be provided separately for each slot. A plurality of integrated units may be provided for every several slots. Alternatively, it may be common to all slots. Further, the microwave feeder need not be an endless or annular waveguide as long as it has a plurality of slots.

The material of the sheet-like dielectric window 4 used in the plasma processing apparatus of the present invention does not need to have a high mechanical strength because it is not necessary to perform vacuum sealing, so that the microwave transmittance is sufficiently high. For example, inorganic substances such as silicon oxide, silicon nitride, calcium fluoride, aluminum oxide, and aluminum nitride, or organic substances such as polyimide and polyfluorocarbon can be used.

The thickness of the dielectric window 4 used in the plasma processing apparatus of the present invention is suitably 5 mm or less because the thinner the shape, the stronger the microwave electric field that appears in the plasma processing chamber and the higher the density of the plasma. The lower limit is about 10 μm.

The slotted microwave supplier 3 used in the plasma processing apparatus of the present invention can be made of a conductive material. However, in order to minimize the propagation loss of the microwave, Al with high conductivity is used. Optimum is Cu, Ag / Cu-plated stainless steel, or the like. As long as the microwave introduction port 13 can efficiently introduce microwaves into the waveguide 13, the microwave introduction port 13 can be introduced in the tangential direction of the annular waveguide parallel to the H plane or perpendicular to the H plane at the introduction portion. It may be a two-way distribution on the left and right sides of the propagation space. The shape of the slot 33 used in the present invention may be rectangular, elliptical, or array-shaped, as long as the length in the direction perpendicular to the microwave propagation direction is at least １ ／ of the guide wavelength. The slot interval is optimally ま た は or の of the guide wavelength so that the electric field crossing the slot due to interference is strengthened. FIG. 7 shows another conductive plate used in the present invention. The slot 33 is a discontinuous straight line.

C1 indicates the center of the waveguide, C2 and C5 indicate the centers of the slots, and C3 and C4 indicate the positions of the side ends of the waveguide.

The microwave frequency used in the present invention is:
It can be appropriately selected from the range of 0.8 GHz to 20 GHz.

As the microwave-transmitting sealing body used in the present invention, SiO ₂ -based quartz, various glasses, Si ₃
N ₄ , NaCl, KCl, LiF, CaF ₂ , BaF
Inorganic substances such as ₂ , Al ₂ O ₃ , AlN, and MgO are suitable, but organic substances such as polyethylene, polyester, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, and polyimide are also applicable. is there.

In the microwave plasma processing apparatus and method of the present invention, a magnetic field generating means may be used. As the magnetic field used in the present invention, a mirror magnetic field or the like can be applied, but the magnetron magnetic field near the slot is optimally a magnetron magnetic field larger than the magnetic field near the substrate. 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.

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

The pressure in the plasma processing chamber of the present invention is 1.3.
3 × 10 ^-2 Pa to 1.33 × 10 ³ Pa range, more preferably, in the case of CVD 1.33 × 10 ^-1 Pa to 1.33 × 10 ¹ Pa, when the etching 6.65 × 1
0 ^-2 Pa to 6.65 Pa, in the case of ashing 1.33
It can be selected from the range of × 10 ¹ Pa to 1.33 × 10 ³ Pa.

The plasma processing method according to the present invention will be described with reference to FIG.

As shown in FIG. 8A, a surface of an object to be processed 101 such as a silicon substrate is coated with silicon oxide, silicon nitride, silicon nitride oxide, aluminum oxide, tantalum oxide or the like by a CVD apparatus or a surface reforming apparatus. Is formed, or an insulating film 102 made of an organic material such as tetrafluoroethylene or polyaryl ether is formed.

As shown in FIG. 8B, a photoresist is applied and baked to form a photoresist layer 103.
To form

As shown in FIG. 8C, a hole pattern latent image is formed by an exposure device, and is developed to form a photoresist pattern 103 'having a hole 104.

As shown in FIG. 8D, a hole 105 is formed by etching the insulating film 102 under the photoresist pattern 103 'using an etching apparatus.

As shown in FIG. 8E, the photoresist pattern 103 'is removed by ashing using an ashing device.

Thus, a structure having the insulating film with holes is obtained.

Subsequently, when depositing a conductor or the like in the hole, it is also preferable to previously clean the inside of the hole with a cleaning device or the like.

The plasma processing apparatus according to the present invention can be used as at least one of a CVD apparatus, a surface reforming apparatus, an etching apparatus, and an ashing apparatus used in the above-described steps.

FIG. 9 shows another plasma processing method according to the present invention.

As shown in FIG. 9A, aluminum,
A conductor pattern (here, line and space) made of a metal such as copper, molybdenum, chromium, and tungsten or various alloys containing at least one of these metals as a main component is formed.

As shown in FIG. 9B, an insulating film 107 is formed by a CVD apparatus or the like.

After a photoresist pattern (not shown) is formed, holes 108 are formed in insulating film 107 by an etching apparatus.
To form

When the photoresist pattern is removed by an ashing device or the like, a structure as shown in FIG. 9C is obtained.

The plasma processing apparatus of the present invention can be used as the above-described CVD apparatus, etching apparatus, and ashing apparatus, but is not limited to these as described later.

The formation of the deposited film by the microwave plasma processing method of the present invention can be performed by appropriately selecting a gas to be used, by using Si ₃ N ₄ , SiO ₂ , Ta ₂ O ₅ , TiO ₂ , T
an insulating film such as iN, Al ₂ O ₃ , AlN, MgF ₂ ,
semiconductor films such as a-Si, poly-Si, SiC, and GaAs; metal films such as Al, W, Mo, Ti, and Ta;
Various deposited films can be formed efficiently.

The object to be processed by the plasma processing method of the present invention may be a semiconductor, a conductive material, or an electrically insulating material. Si wafers, SOI wafers and the like can be mentioned.

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 quartz glass and various other glasses, Si ₃ N ₄ , NaCl, KCl, L
iF, CaF ₂ , BaF ₂ , Al ₂ O ₃ , AlN, M
inorganic films such as gO, films of organic materials such as polyethylene, polyester, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, and polyimide;
A sheet and the like.

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

In the case of forming a Si-based semiconductor thin film such as a-Si, poly-Si, or SiC, the source gas containing Si atoms includes inorganic silanes such as SiH ₄ and Si ₂ H ₆ and tetraethylsilane (TES). ), Organic silanes such as tetramethylsilane (TMS), dimethylsilane (DMS), dimethyldifluorosilane (DMDFS), dimethyldichlorosilane (DMDCS), SiF ₄ ,
Si ₂ H ₆ , Si ₃ F ₈ , SiHF ₃ , SiH ₂ F ₂ ,
SiCl ₄ , Si ₂ Cl ₆ , SiHCl ₃ , SiH ₂ C
Halosilanes such as l ₂ , SiH ₃ Cl, SiCl ₂ F ₂ and the like, which are in a gaseous state at normal temperature and pressure or 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 includes H ₂ , He, Ne, Ar, Kr, Xe,
Rn.

When forming a Si compound based thin film such as Si ₃ N ₄ or SiO ₂ , the raw materials containing Si atoms include inorganic silanes such as SiH ₄ and Si ₂ H ₆ , tetraethoxysilane (TEOS), Tetramethoxysilane (TMOS), octamethylcyclotetrasilane (OM
CTS), dimethyldifluorosilane (DMDFS),
Organosilanes such as dimethyldichlorosilane (DMDCS), SiF ₄ , Si ₂ F ₆ , Si ₃ F ₈ , SiHF
₃ , SiH ₂ F ₂ , SiCl ₄ , Si ₂ Cl ₆ , SiH
Cl ₃ , SiH ₂ Cl ₂ , SiH ₃ Cl, SiCl ₂ F
Examples include halogenated silanes such as ₂ , which are in a gaseous state at normal temperature and pressure, or those which can be easily gasified.
In this case, the nitrogen source gas or the oxygen source gas introduced simultaneously may be N ₂ , NH ₃ , N ₂ H ₄ , hexamethyldisilazane (HMDS), O ₂ , O ₃ , H ₂ O,
NO, N ₂ O, NO _{2 and the} like can be mentioned.

The raw materials containing metal atoms when forming a metal thin film of Al, W, Mo, Ti, Ta, etc. are as follows:
Trimethylaluminum (TMAl), triethylaluminum (TEAl), triisobutylaluminum (TIBAl), dimethylaluminum hydride (DMAIH), tungsten carbonyl (W (CO)
₆ ), molybdenum carbonyl (Mo (CO) ₆ ), trimethylgallium (TMGa), triethylgallium (T
Organic metals such as EGa), AlCl ₃ , WF ₆ , TiC
l _3, metal halide, etc., such as TaCl ₅ and the like. In this case, the additive gas or carrier gas which may be mixed with the Si source gas and introduced is H ₂ , H
e, Ne, Ar, Kr, Xe, and Rn.

Al ₂ O ₃ , AlN, Ta ₂ O ₅ , TiO
Raw materials containing metal atoms when forming a thin film of a metal compound such as ₂ , TiN and WO ₃ are trimethylaluminum (TMAl), triethylaluminum (TE
Al), triisobutylaluminum (TIBAl),
Dimethyl aluminum hydride (DMAlH), tungsten carbonyl (W (CO) ₆ ), molybdenum carbonyl (Mo (CO) ₆ ), trimethylgallium (T
Organic metal such as MGa) and triethylgallium (TEGa), and metal halides such as AlCl ₃ , WF ₆ , TiCl ₃ , and TaCl ₅ . In this case, the oxygen source gas or the nitrogen source gas introduced simultaneously may be O ₂ , O ₃ , H ₂ O, NO, N ₂ O, NO ₂ , N _2
2 , NH ₃ , N ₂ H ₄ , hexamethyldisilazane (HM
DS).

As the etching gas for etching the substrate surface, F ₂ , CF ₄ , CH ₂ F ₂ , C ₂ F
₆ , C ₄ F ₈ , CF ₂ Cl ₂ , SF ₆ , NF ₃ , Cl
₂ , CCl ₄ , CH ₂ Cl ₂ , C ₂ Cl _{6 and the} like.

When removing organic components such as a photoresist on the surface of a substrate by ashing, the ashing gas is as follows:
O ₂ , O ₃ , H ₂ O, N ₂ , NO, N ₂ O, NO _{2 and the} like can be mentioned.

When the microwave plasma processing apparatus and the processing method of the present invention are 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. When the substrate or surface layer is oxidized or nitrided by using a method such as B, As, P or the like, a doping process or the like can be performed. Further, the present invention can be applied to a cleaning method.
In that case, it can be used for cleaning to remove oxides, organic substances, heavy metals, and the like.

Oxidizing gases used for oxidizing surface treatment of the substrate include O ₂ , O ₃ , H ₂ O, NO, N ₂ O, and NO ₂
And the like. Further, as the nitriding gas when the substrate is subjected to the nitriding surface treatment, N ₂ , NH ₃ , N ₂ H ₄ , hexamethyldisilazane (HMDS) and the like can be mentioned.

O ₂ , O ₃ , H ₂ O, H ₂ , NO are used as cleaning / ashing gases for cleaning organic substances on the surface of the substrate or ashing for removing organic components such as photoresist on the surface of the substrate. , N ₂
O, NO _{2 and the} like. Further, as cleaning gases for cleaning inorganic substances on the surface of the substrate, F ₂ , CF ₄ , CH ₂ F ₂ , C ₂ F ₆ , C ₄ F ₈ ,
CF ₂ Cl ₂ , SF ₆ , NF _{3 and the} like.

(Embodiment 1) The structure of the microwave plasma processing apparatus of this embodiment is as shown in FIG. A donut-shaped quartz sealing body was arranged inside the waveguide so as to cover each slot.

The material of the dielectric window is made of anhydrous synthetic quartz,
The thickness was 3 mm. The endless annular waveguide 13 has an inner wall cross-sectional dimension of 27 mm × 96 mm, a central diameter of the waveguide of 202 mm, and a circumference of four times (4λg) the in-path wavelength. The material of the microwave supplier 3 is all A1 in order to suppress the propagation loss of the microwave. Slots for introducing microwaves into the plasma processing chamber are formed on the H surface of the endless annular waveguide 13. The shape of the slot is a rectangle having a length of 40 mm and a width of 4 mm. The slots are arranged at a half interval of the guide wavelength so that the length direction is perpendicular to the traveling direction of the microwave. The wavelength in the waveguide is
Depending on the frequency of the microwave used and the dimensions of the cross section of the waveguide, a microwave of frequency 2.45 GHz,
When the waveguide having the above dimensions is used, the distance is about 159 mm. Eight slots provided in the annular waveguide are formed radially at intervals of about 45 degrees. A microwave power supply that oscillates a microwave having a frequency of 2.45 GHz is sequentially connected to the microwave supply path 3 via a 4E tuner, a directional coupler, and an isolator.

The plasma processing is performed as follows.
The inside of the container 1 is evacuated through the evacuation system 8. Subsequently, the processing gas is introduced into the plasma processing chamber at a predetermined flow rate through gas supply means 7 provided around the plasma processing chamber in the container. Next, the conductance valve provided in the exhaust system 8 is adjusted to maintain the inside of the container at a predetermined pressure. A desired microwave power is supplied from the microwave power supply to the plasma processing chamber through the slot and the dielectric window 4 via the microwave supply 3. At this time, the processing gas introduced from the periphery
The generated high-density plasma activates, excites, ionizes, reacts, and is supplied to the surface of the workpiece W placed on the support 2.

Using this device, Ar was flowed as a processing gas at a flow rate of 100 sccm, a discharge was performed under the conditions of a pressure of 1.33 Pa and a microwave power of 3 kW, and the electron density distribution was measured using a Langmuir probe capable of scanning. As a result, a high-density uniform plasma of 2.5 × 10 ¹² cm ⁻³ ± 2.7% was generated.

Embodiment 2 Another example of the microwave plasma processing apparatus of the present invention will be described with reference to FIG. A sealing body 14 using a quartz window having an end extending from the slot by several mm to several tens mm is provided outside the waveguide 13 so as to cover each slot.

FIG. 11 shows the size relationship of the size of the sealing body 14 corresponding to one slot 33.

The material of the dielectric sheet window 4 was made of anhydrous synthetic quartz. The dimensions of the cross section of the waveguide are 27 mm × 96 mm, the center diameter of the waveguide is 202 mm, and the circumference is 4λg. The material of the microwave supplier 3 is all A1 in order to suppress the propagation loss of the microwave. Slots for introducing microwaves into the plasma processing chamber are formed in the conductive plate with slots serving as the H-plane of the annular waveguide 13. The slots have a rectangular shape with a length of 40 mm and a width of 4 mm, and are arranged at a half interval of the guide wavelength. The guide wavelength depends on the frequency of the microwave used and the cross-sectional dimension of the waveguide, but the frequency is 2.45 GHz.
It is about 159 mm when using a microwave of z and a waveguide of the above dimensions. Eight slots are formed radially at intervals of about 45 degrees in the conductor plate. A microwave power supply (not shown) that oscillates a microwave having a frequency of 2.45 GHz is sequentially connected to the microwave supply path 3 via a 4E tuner, a directional supply, and an isolator.

The plasma processing is performed as follows. The inside of the plasma container 1 is evacuated via the exhaust system 8. Subsequently, a processing gas is introduced into the plasma processing chamber at a predetermined flow rate through gas supply means 7 provided around the plasma processing chamber. Next, the conductance valve provided in the exhaust system 8 is adjusted to maintain the plasma processing chamber at a predetermined pressure. Desired power is supplied from a microwave power supply (not shown) to the plasma processing chamber via the microwave supply device 3. At this time, the processing gas introduced from the periphery is excited, ionized, and activated by the generated high-density plasma to be activated and applied to the surface of the processing object W placed on the support 2.
Thus, the object to be processed W is processed at a high speed.

Using this apparatus, Ar was supplied at 100 scc
m, pressure 1.33 Pa, and microwave power 3 kW, and electron density distribution was measured using a scanning Langmuir probe. As a result, 2.0 ×
A high-density uniform plasma of 10 ¹² cm ^-3 ± 2.4% was generated.

Example 3 Ashing of a photoresist was performed using the microwave plasma processing apparatus shown in FIGS.

As the object to be processed W, an insulating film made of silicon oxide under the photoresist pattern is etched,
Immediately after forming a via hole, the silicon substrate (diameter 300)
mm). First, after the silicon substrate was placed on the holding means 2, the vessel was heated to 200 ° C. and the inside of the container 1 was evacuated via the exhaust system to reduce the pressure to 1.33 × 10 ⁻² Pa. 2 s of oxygen gas through the processing gas supply port 17
It was introduced into the vessel 1 at a flow rate of 1 m. Next, the conductance valve 28 provided in the exhaust system was adjusted to keep the inside of the container 1 at 133 Pa. Power of 2.5 kW and 2.45 GHz was supplied from the microwave power supply 6 to the container 1 via the microwave supply device 3. Thus, plasma was generated in the space 9. At this time, the oxygen gas introduced through the processing gas supply port 17 is excited, decomposed and reacted in the space 9 to become ozone, and is imported in the direction of the silicon substrate W.
The photoresist on the substrate W was oxidized, vaporized and removed. After the ashing, the ashing speed and the substrate surface charge density were evaluated.

The obtained ashing speed and uniformity were very good, 7.5 μm / min, ± 4.2%. The surface charge density showed a sufficiently low value of 0.5 × 10 ¹¹ / cm ² .

Example 4 Ashing of a photoresist was performed using the microwave plasma processing apparatus shown in FIGS. The object to be processed W was the same as that in Example 3.

After the object to be processed W was set, it was heated to 200 ° C. using a heater, and the plasma processing chamber was evacuated to a vacuum of 1.33 × 10 ⁻² Pa through the exhaust system 8.
2 sl of oxygen gas is supplied through the plasma processing gas supply port 7.
m. Next, the conductance valve provided in the exhaust system 8 was adjusted to maintain the inside of the container 1 at 266 Pa. 2.5kw 2.45G in plasma processing chamber
Hz microwave power was supplied via the microwave supplier 3. Thus, plasma was generated in the plasma processing chamber. After the ashing, the ashing speed and the substrate surface charge density were evaluated.

The obtained ashing speed was 8.6 μm /
min and a surface charge density of 1.2 × 10 ¹¹
The value was sufficiently low at cm ^-2 .

Example 5 A silicon nitride film for protecting semiconductor elements was formed using the microwave plasma processing apparatus shown in FIGS.

As the object to be processed W, a P-type single-crystal silicon substrate with an insulating film made of silicon oxide on which an A1 wiring pattern having a line and space of 0.5 μm is formed (plane orientation <100>, resistivity 10 Ωcm) It was used. First, after placing the silicon substrate on the holding means 2,
The inside of the container 1 is evacuated through the evacuation system, and 1.33 × 10 ⁻⁵ P
The pressure was reduced to the value of a. Subsequently, a heater (not shown) attached to the holding means 2 was energized to heat the silicon substrate to 300 ° C. and hold it. At a flow rate of 600 sccm of nitrogen gas and 200 silane of monosilane gas through the processing gas supply port 17,
It was introduced into the container 1 at a flow rate of sccm. Next, the conductance valve 28 provided in the exhaust system was adjusted to maintain the inside of the container 1 at 2.66 Pa. Then, 3.0 kW, 2.45 GHz power was supplied from the microwave power supply 6 through the microwave supply device 3. Thus, plasma was generated in the space 9. At this time, it is excited and decomposed in the nitrogen gas space 9 introduced through the processing gas supply port 17 to become an active species, is transported in the direction of the silicon substrate, reacts with the monosilane gas, and forms a silicon nitride film on the silicon substrate. Was formed with a thickness of 1.0 μm. After 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 rate of film formation of the obtained silicon nitride film is 6
It was 20 nm / min. The stress is 1.1 × 10 ⁹ dy
ne / cm ² (compression), leakage current is 1.2 × 10 ^-10
A / cm ² and the withstand voltage were 10.3 MV / cm, and it was confirmed that the film was extremely high quality.

Example 6 Using the microwave plasma processing apparatus shown in FIGS. 10 and 11, a silicon oxide film and a silicon nitride film for preventing plastic lens reflection were formed.

As the object to be processed W, a plastic convex lens having a diameter of 50 mm was used. After placing the lens on the holding means 2, the inside of the container 1 is evacuated through the exhaust system, and 1.33 is set.
The pressure was reduced to a value of × 10 ⁻⁵ Pa. Processing gas supply port 1
7 at a flow rate of 150 sccm of nitrogen gas;
Monosilane gas was introduced into the container 1 at a flow rate of 100 sccm. Next, the conductance valve provided in the exhaust system was adjusted, and the inside of the container 1 was maintained at 9.32 × 10 ⁻¹ Pa. Then, 3.0 kW, 2.
The 45 GHz power is supplied to the container 1 via the microwave feeder 3.
Supplied within. Thus, plasma was generated in the space 9. At this time, the nitrogen gas introduced through the processing gas supply port 17 is excited and decomposed in the space 9 to become active species such as nitrogen atoms, is transported in the direction of the lens, reacts with the monosilane gas, and reacts with the silicon nitride. A film is placed on the lens surface
It was formed with a thickness of 10 nm.

Next, oxygen is supplied through the processing gas supply port 17.
The gas was supplied at a flow rate of 200 sccm,
Was introduced into the container 1 at a flow rate of 100 sccm. About
Adjust the conductance valve 8 provided in the exhaust system
And the inside of the container 1 is 1.33 × 10 ^-1It was kept at Pa. About
2.0 kW, 2.45 GHz from the microwave power source 6
Is supplied into the container 1 via the microwave supply 3.
Was. Thus, plasma was generated in the space 9. this
At this time, the introduced oxygen gas is excited and decomposed in the space 9.
It becomes active species such as oxygen atoms and is transported in the direction of the lens.
Reacts with the monosilane gas to form a silicon oxide film on the lens.
It was formed on top with a thickness of 85 nm. After film formation, film formation speed,
The reflection characteristics were evaluated.

The film formation rate and uniformity of the obtained silicon nitride film and silicon oxide film were 370 nm / mi, respectively.
n, 400 nm / min. In addition, the reflectance around 500 nm was 0.17%, and it was confirmed that the optical characteristics were very good.

Example 7 An interlayer insulating film of a semiconductor element was formed by using the microwave plasma processing apparatus shown in FIGS.

As the object to be processed W, a P-type single-crystal silicon substrate (plane orientation <100>, resistivity 10Ω) on which an A1 pattern of 0.5 μm line and space is formed on the uppermost part
cm) was used. This silicon substrate was set on the holding means. The inside of the container 1 is evacuated via the exhaust system to 1.3
The pressure was reduced to 3 × 10 ⁻⁵ Pa. Subsequently, a heater attached to the holding means is energized to heat the silicon substrate to 300 ° C.
Held. Nitrogen gas 50 through processing gas supply port 17
At a flow rate of 0 sccm, and monosilane gas at 200 sc
at a flow rate of 1 cm. Next, the conductance valve 8 provided in the exhaust system was adjusted to maintain the inside of the container 1 at 4.00 Pa. Then, 300 W.V. was applied through a bias voltage applying means attached to the holding means. 13.56M
Hz high-frequency power is applied to the holding means 2,
Power of 2.0 kW and 2.45 GHz was supplied from the microwave power supply 6 into the container 1 through the microwave supply pipe 3.
Thus, plasma was generated in the space 9. Excited and decomposed in the nitrogen gas space 9 introduced through the processing gas supply port 17 to become active species, transported in the direction of the silicon substrate, reacted with the monosilane gas, and formed a silicon oxide film on the silicon substrate. It was formed with a thickness of 8 μm. At this time, the ion species are accelerated by the PF bias and are incident on the substrate to cut the silicon oxide film on the A1 pattern to improve the flatness. After the treatment, the film formation rate, uniformity, insulation resistance, and step coverage were evaluated. The step coverage was evaluated by observing a cross section of the silicon oxide film formed on the A1 pattern with a scanning electron microscope (SEM) and observing voids.

The film formation rate and uniformity of the obtained silicon nitride film were 310 nm / min. Dielectric strength is 9.1
MV / cm, and it was confirmed that the film was void-free and of good quality.

Example 8 Using the microwave plasma processing apparatus shown in FIGS. 10 and 11, the interlayer insulating film of the semiconductor element was etched.

As an object to be processed W, a P-type single crystal silicon substrate (plane orientation <10 °) in which an insulating film made of silicon oxide having a thickness of 1 μm is formed on an A1 pattern having a line and space of 0.35 μm and a photoresist pattern is formed thereon.
0>, resistivity 10 Ωcm). First, the silicon substrate was set on the holding means 2. The inside of the container 1 was evacuated through the evacuation system, and the pressure was reduced to 1.33 × 10 ⁻⁵ Pa. CF ₄ was introduced into the container 1 through the processing gas supply port 17 at a flow rate of 300 sccm. Next, the conductance valve 8 provided in the exhaust system was adjusted, and
It was kept at Pa. Next, high-frequency power of 300 W, 400 kHz is applied to the holding means 2 via a bias voltage applying means attached to the holding means, and power of 3.0 kW, 2.45 GHz is supplied from the microwave power supply to the microwave supply device 3. Into the container 1 via Thus, plasma was generated in the space 9. Excited and decomposed into active species in the CF ₄ gas space 9 introduced through the processing gas supply port 17 to become an active species, transported in the direction of the silicon substrate, and made of silicon oxide by ions accelerated by self-bias Was etched to form a hole.
The cooler (not shown) attached to the holding means 2 only raised the substrate temperature to 90 ° 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 silicon oxide film with a scanning electron microscope (SEM).

The etching rate and uniformity and the selectivity to polysilicon were 720 nm / min and 20, respectively. The hole had a substantially vertical side surface, and it was confirmed that the microloading effect was small.

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 object to be processed, a P-type single-crystal silicon substrate having a diameter of 300 mm (plane orientation <100>, low efficiency 10 Ωcm) having a polysilicon film formed on the uppermost portion was used.
First, after the workpiece W was installed, the inside of the container 1 was evacuated via the exhaust system 8 to reduce the pressure to 1.33 × 10 ⁻⁵ Pa. 300 scf CF ₄ gas as processing gas
m and oxygen were introduced into the container 1 at a flow rate of 20 sccm.
Next, the conductance valve provided in the exhaust system 8 was adjusted, and the pressure in the container 1 was maintained at 0.266 Pa.
Next, the high frequency power 3 from the 400 kHz high frequency power supply
00W is applied to the support 2, and 2.0 kW,
Microwave power of 3.45 GHz
And supplied into the container 1 through Thus, plasma was generated in the plasma processing chamber. The introduced CF ₄ gas and oxygen were excited and decomposed in the plasma processing chamber to become active species, transported in the direction of the workpiece W, and the polysilicon film was etched by the ions accelerated by the self-bias. Due to the cooler, the substrate temperature rose 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 etching rate and the selectivity to SiO ₂ were as good as 850 nm / min and 24, respectively. It was confirmed that the etching shape was vertical and the microloading effect was small.

[0103]

According to the present invention, since the density of the plasma can be increased, the object to be processed can be favorably processed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a plasma processing apparatus according to the present invention.

FIG. 2 is a plan view showing an example of a flat plate with slots used in the present invention.

FIG. 3 is a plan view showing the state of microwave propagation and radiation.

FIG. 4 is a sectional view showing a structure near a slot.

FIG. 5 is a sectional view showing a structure near a slot.

FIG. 6 is a sectional view showing a structure near a slot.

FIG. 7 is a plan view of another conductive flat plate.

FIG. 8 illustrates an example of a plasma processing method.

FIG. 9 is a diagram showing another example of the plasma processing method.

FIG. 10 is a cross-sectional view of a microwave plasma processing apparatus.

FIG. 11 is a diagram showing a structure near a slot.

FIG. 12 is a diagram showing a configuration of a conventional plasma processing apparatus.

FIG. 13 is a sectional view of a plasma processing apparatus.

FIG. 14 is a diagram showing a state of propagation and radiation of a microwave.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container 2 Processing object holding means 3 Microwave supplier 4 Sheet-shaped dielectric window 5 Waveguide 13 Annular waveguide 14 Sealing body 23 Slotted flat plate 33 Slot

Claims (10)

[Claims] 1. A container whose inside can be evacuated, gas supply means for supplying gas into the container, a microwave supply device for supplying microwaves for generating plasma in the container, A plasma processing apparatus for processing an object to be processed using the plasma, wherein each of the plurality of slots for emitting microwaves provided in the microwave supply device has a dielectric window through which the plasma is transmitted. And a microwave-transparent sealing body, and the dielectric window is formed into a sheet having a thickness of 5 mm or less common to the plurality of slots. 2. The plasma processing apparatus according to claim 1, wherein said dielectric window is made of an inorganic material. 3. The plasma processing apparatus according to claim 1, wherein said dielectric window is made of an organic material. 4. The plasma processing apparatus according to claim 1, wherein said dielectric window is at least one selected from the group consisting of silicon oxide, silicon nitride, calcium fluoride, aluminum oxide, aluminum nitride, polyimide, and polyfluorocarbon. 5. The plasma processing apparatus according to claim 1, wherein the sealing member is provided so as to fill the slot. 6. The plasma processing apparatus according to claim 1, wherein the sealing body is provided inside the microwave waveguide so as to cover the slot. 7. The plasma processing apparatus according to claim 1, wherein the sealing body is provided outside the microwave waveguide so as to cover the slot. 8. A plasma processing method for processing the object using the plasma processing apparatus according to claim 1. 9. The plasma processing method according to claim 8, wherein the plasma processing is at least one of ashing, etching, cleaning, and film formation. 10. A structure processed by the plasma processing method according to claim 1.