JP2001028343A - Thin-film processing method and liquid-crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve purity of a sample by eliminating the constraint on the pressure of gas for processing a sample, while promoting chemical reaction by generation of low molecular weight active species through gas decomposition. SOLUTION: A gas is introduced through a gas inlet 18, so that arc discharge is generated between an anode 24 and a cathode 22, to generate a plasma. An electron beam 34 is extracted from the plasma, and the electron beam 34 is guided into a reaction chamber 14 via a decompression chamber 12. The gas in the reaction chamber 14 is irradiated with electron beam 34 to generates a plasma 50, and a substrate 48 is processed with the plasma 50.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film processing step, and more particularly to a method of irradiating a gas with an electron beam to decompose a part of the gas to generate low molecular active species, thereby promoting a chemical reaction. The present invention relates to a thin film processing step suitable for improving the purity of a sample.

[0002]

2. Description of the Related Art Conventionally, a plasma chemical vapor deposition apparatus and a plasma dry etching apparatus have been known as plasma processing apparatuses. In these devices, a pair of electrodes are arranged in parallel in a container containing a reaction gas so as to face each other, a substrate is arranged as a sample on one of the electrodes, and a high-frequency or DC voltage is applied between the parallel plate electrodes. Is applied to ionize the gas, plasma is generated between the electrodes by ionization of the gas, and the substrate is subjected to a film forming process, an etching process, or the like. For example, the plasma chemical vapor deposition method and the processing apparatus using the same are described in Electrochemical Society (1974, p. 19), and the plasma dry etching method and the processing apparatus using the same are described in the Electrochemical Society (1974, 1978).
Page), plasma etching technology, electronic materials (1978)
Year, pages 54 to 59 are known).

[0003]

In the prior art, the electrodes and the plasma are housed in a single container. Therefore, in order to cause a uniform discharge between the parallel plate electrodes, the gas in the container is The pressure is limited to several Pa (pascal) to several tens Pa. That is, if the gas pressure in the container is higher than the set value, uniform discharge cannot be performed between the electrodes of the parallel plate, and a localized discharge occurs, so that a uniform film forming process cannot be performed on the substrate. Conversely, if the gas pressure in the container is lower than the set value, the discharge becomes unstable or does not discharge at all, and it becomes difficult to perform the film forming process on the substrate.

[0004] It is an object of the present invention to remove restrictions on the pressure of a gas for processing a sample, thereby promoting the chemical reaction by generating low molecular active species by decomposition of the gas, thereby improving the purity of the sample. It is an object of the present invention to provide a thin film processing step suitable for the above.

[0005]

To achieve the above object, the present invention provides an electron beam source for generating an electron beam;
A reaction chamber for storing the gas together with the sample, introducing the electron beam into an atmosphere filled with the gas, ionizing the gas, generating plasma by ionization of the gas, and processing the sample;
A thin film processing apparatus comprising: a separation unit disposed between the electron beam source and the reaction chamber to separate them from each other and form an electron beam transmission path for guiding an electron beam from the electron beam source to the reaction chamber. It constitutes the process.
In constituting the thin film processing step, instead of the separating means, as a space portion having a pressure lower than the gas pressure of the reaction chamber, the space portion is disposed between the electron beam source and the reaction chamber and is separated from the electron beam source. A decompression chamber for guiding the electron beam to the reaction chamber can be provided. Furthermore, as a reaction chamber,
The sample may be configured to have a function of irradiating the sample with an electron beam from an electron beam source to heat the sample.

In configuring each of the plasma processing apparatuses, the following elements can be added.

(1) The electron beam source has an electric field lens for narrowing the beam diameter of the electron beam. The electric field lens generates a single electron beam, and passes through the electric field lens in the decompression chamber. And a magnetic field lens for reducing the beam diameter of the electron beam.

(2) The electron beam source has an electric field lens for narrowing the beam diameter of the electron beam, the electric field lens generates a single electron beam, and has a plurality of decompression chambers. The decompression chambers are arranged adjacent to each other, and in each of the decompression chambers, a magnetic field lens for reducing the beam diameter of the electron beam passing through the electric field lens or the electron beam passing through another decompression chamber is disposed.

(3) Charge amount adjusting means for adjusting the charge amount of the sample accompanying the irradiation of the electron beam, and adjusting the neutralization amount of positive ions contained in the plasma in the processing chamber by flowing into the sample. And a neutralization amount adjusting means.

(4) The electron beam source comprises: a container for introducing and storing a gas; generating an arc discharge in the container in response to a pulse signal and emitting thermal electrons to generate plasma in the container. A pair of electrodes to be generated, pulse signal adjusting means for adjusting a pulse width and a pulse interval of a pulse signal applied between the pair of electrodes, and a plurality of extraction electrodes for extracting an electron beam from inside the container by applying a voltage, Voltage adjusting means for adjusting a voltage applied between the plurality of extraction electrodes, and a gas pressure adjusting means for adjusting a gas pressure of the reaction chamber is connected to the reaction chamber.

(5) The reaction chamber is provided with a magnetic material for forming a magnetic field around the sample and confining the plasma in the reaction chamber to the surface of the sample to be processed.

(6) At least SiF ₄ ,
SiCl ₄ , SiH ₄ , MgCl ₃ , SiBr ₄ , MgB
r ₃ , AlCl ₃ , PCl ₃ , PBr ₃ , PH ₃ , Ti
Cl ₄ , CrCl ₃ , CuCl ₂ , CCl ₄ , Cu ₂ Cl
₂ , GeCl ₄ , AsCl ₃ , AsH ₃ , ZrF ₃ , A
gCl, AgBr, InCl ₃ , InBr ₃ , SnC
_{l 4, NdCl 3, LaCl 3} , CeCl 3, PrCl
₃ , SmCl ₃ , SmCl ₂ , EuCl ₃ , EuCl ₂ ,
GdCl ₃ , TbCl ₃ , DyCl ₃ , HoCl ₃ , E
_{rCl 3, TmCl 3, YbCl 3} , LuCl 3, CO
_{2, B 2 H 6, GeH} 4, SiI 4, AsO 3, Si 3 N 4,
CH ₄ , O ₂ , N ₂ , N ₂ O, Si (OCH ₃ ) ₃ , Si ₂ H
₆ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄
H ₉ ) ₄ , Si ₃ H ₈ , SiF (OC ₂ H ₅ ) ₃ , SiH ₂ F ₂ , S
One of iH ₂ Cl ₂ , SiHCl ₃ and SiI ₄ is used.

(7) The step of processing the sample on the substrate is performed in a chamber in which the inner wall of the chamber is coated with Si.

According to the above-mentioned means, since the electron beam source and the reaction chamber are separated by the separation means or the decompression chamber, the gas pressure in the reaction chamber where the processing gas is present is reduced, for example, by film formation, etching, etc. It can be set to any gas pressure that is optimal for plasma processing such as oxidation, nitriding, and the like. Eliminating restrictions on the gas pressure for processing the sample, generating a density of low-molecular-weight active species by decomposing the gas, promoting a chemical reaction, and improving the thin film processing process suitable for improving the purity of the sample. This can improve the purity of the film. For example, in the formation of a Si film using SiF ₄ gas, active species are Si ⁺ , SiF ⁺ , SiF ₂ ⁺ , Si
Although F ₃ ^{+ and the} like are generated, the production ratio of Si ⁺ and SiF ⁺ is increased and the activity is improved, so that the amount of impurities taken into the formed Si film is reduced. Further, according to this method, the flatness of the film surface or the flatness of the multilayer film interface during continuous film formation is improved. By changing the processing gas, a semiconductor film, an n-type or p-type doped semiconductor film, an insulating film, an electrode film, and the like used for a liquid crystal element, a semiconductor element, a solar cell element, and the like can be continuously formed. . Further, by processing the sample on the substrate in a chamber in which the inner wall of the chamber is coated with Si, the amount of impurities mixed into the Si semiconductor element, which is easily affected by impurities, is stabilized, and a Si semiconductor element having stable electric characteristics is formed. Becomes possible. In addition, the potential of the sample can be controlled by adjusting the charge amount of the sample accompanying the irradiation of the electron beam and adjusting the neutralization amount due to the inflow of the positive ions contained in the plasma in the reaction chamber into the sample, It is possible to prevent the occurrence of charge caused by the electron beam on the surface of the sample and the occurrence of discharge breakdown beforehand. Furthermore, by confining the plasma in the reaction chamber to the surface of the sample to be processed by the magnetic field of the magnetic substance placed in the reaction chamber, the plasma density on the sample surface can be increased and the charge by the electron beam can be reduced.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

(Example 1) FIG. 1 is a longitudinal sectional view of a plasma processing apparatus for performing one embodiment of a thin film processing step of the present invention. In FIG. 1, the plasma processing apparatus is an electron beam source 10, a decompression chamber 12,
The electron beam source 10 is disposed on the reaction chamber 14 via the decompression chamber 12.
The electron beam source 10 is a container 1 forming a plasma generation chamber.
The container 16 is formed in a box-like shape with one end closed in the axial direction and the other end opened. A gas inlet 18 is formed on the upper side of the container 16, and helium gas or hydrogen gas is introduced into the container 16 from the gas inlet 18. A plurality of insulating materials 20 are fixed to the walls on both sides of the gas inlet 18 in a state penetrating the walls, and a cathode (negative electrode) 22 made of tungsten is inserted into each insulating material 20. Each cathode 22 is connected as a hot filament to a negative DC power supply, and each cathode 22 emits thermoelectrons. Container 1
An anode (positive electrode) 24 is provided on the inner wall surface of 6, and this anode 24 is connected to a positive DC power supply. When a DC voltage is applied between the anode 24 and the cathode 22 from a DC power supply, an arc discharge occurs between the electrodes, and a single plasma is formed in the container 16. A plurality of permanent magnets 26 are arranged on the outer peripheral side of the container 16 as a magnetic material. Each permanent magnet 26 is arranged so that the N pole and the S pole are alternated, that is, the magnetic poles of the other adjacent permanent magnets 26 are different from each other, and a multipolar magnetic field is formed by each permanent magnet 26. It has become. By this multi-pole magnetic field, a single plasma formed in the container 16 is
It is designed to be confined inside. On the other hand, the container 16
A plurality of extraction electrodes 28 and 30 are arranged on the opening end side of the opening and spaced apart from each other, for example, with an insulation distance of about 1 to 5 mm. The extraction electrode 28 is connected to a negative DC power source, and the extraction electrode 30 is grounded.
A plurality of extraction electrode holes 32 are formed in 30. For example, 300 extraction electrode holes 32 having a diameter of 3 mm are formed. When a DC voltage is applied between the extraction electrodes 28 and 30 in a state where the plasma is generated in the container 16, the electron beam 34 is extracted from the plasma. In this case, by extracting the electron beam 34 from each extraction electrode hole 32, 300 electron beams 34 are extracted from the plasma in the container 16. The energy of the extracted electron beam 34 is
For example, about 1 keV, 300 electron beams 34
As a result, an electron beam 34 having an output electron beam amount of 1000 mA is extracted into the decompression chamber 12. The decompression chamber 12
As a separating means which is disposed between the electron beam source 10 and the reaction chamber 14 to separate them and form an electron beam transmission path for guiding the electron beam 34 from the electron beam source 10 to the reaction chamber 14, it is formed in a rectangular parallelepiped shape. Exhaust port 3
6 is connected to a vacuum pump. That is, the decompression chamber 12
Is defined as a space having a pressure lower than the gas pressure of the reaction chamber 14 by a vacuum pump,
Pressure is maintained to a certain degree. The decompression chamber 12 and the reaction chamber 1
The partition wall 38, which is a boundary with 4, has 300 electron beam passage holes 40 having a diameter of 3 mm, and 300 electron beams 34 are introduced into the reaction chamber 14 through each electron beam passage hole 40. It has become. Further, when forming each electron beam passage hole 40 in the partition wall 38, it is possible to form the electron beam passage hole 40 by mechanical processing. However, by increasing the differential pressure between the reaction chamber 14 and the decompression chamber 12, the load on the vacuum pump is increased. In order to reduce the size, three holes with a diameter of 1 mm or less
It is desirable to open 00 pieces. However, it is difficult to ensure that all of the 300 electron beams 34 pass through the respective electron beam passage holes 40 without being decentered by alignment by machining. Therefore, in the present embodiment, after assembling the reaction chamber 14, the decompression chamber 12, and the electron beam source 10, the electron beam 34 from the electron beam source 10 is irradiated to the partition 38 on the flat plate. Is used to form the electron beam passage hole 40. By employing this method, the diameter of the electron beam passage hole 40 can be made substantially the same as the beam diameter of the electron beam 34, and the eccentricity of the electron beam 34 can be made zero.

On the other hand, the reaction chamber 14 is 50 cm high and 80 cm wide.
The reaction chamber 14 has a gas inlet 42 and an exhaust port 4 at the bottom of the reaction chamber 14.
4 are formed. In the reaction chamber 14, when, for example, silicon tetrafluoride gas is used as a processing gas from the gas inlet 42, a film is formed on the substrate 48. That is, by heating the substrate 48 to a temperature optimal for film formation, a thin film of a material decomposed by plasma, for example, Si can be grown on the substrate 48. Part of the gas in the reaction chamber 14 is exhausted from the exhaust port 44. This exhaust port 44 is connected to a vacuum pump,
By operating the vacuum pump, the gas pressure in the reaction chamber 14 is maintained at, for example, about 1 to 10 Pa. A substrate holder 46 is fixed substantially at the center of the reaction chamber 14, and the reaction chamber 14 containing the gas together with the substrate 48 is filled with the gas, and 300 electron beams 34 are introduced into this atmosphere. Then, the gas is ionized and plasma 50 is generated.
A thin film of Si is formed. The ratio of active species Si ⁺ , SiF ⁺ , SiF ₂ ⁺ , and SiF ₃ ⁺ contained in the plasma is 6: 1.
5: 2: 1, resulting in a high generation ratio of Si ⁺ and SiF ⁺ . Table 1 shows the results of examining the structure, crystallinity, and field-effect mobility of the Si film when the substrate temperature was set at 20, 200, and 400 ° C.

[0018]

[Table 1]

The composition analysis of these Si films was performed by secondary ion mass spectrometry (SIMS). As a result, the following results were obtained irrespective of the film forming conditions. Si ⁺ , S
iO ⁺ was detected, SiO ⁺ was due to a surface oxide layer having a thickness of about 1 n, and the oxygen content inside the film was 6 × 10 ¹⁷ cm.
^{Was -3} . The other trace elements detected were carbon, nitrogen, fluorine and hydrogen, the content of which was 5 × 10 ¹⁷ c
m ⁻³ , 3 × 10 ¹⁷ cm ⁻³ , 7 × 10 ¹⁷ cm ⁻³ , 7 × 10 ¹⁷ cm
^-3 , and a high-purity Si film having an impurity content of 7 × 10 ¹⁷ cm ⁻³ or less was formed. Sodium and chlorine are the detection limits. From the observation of the cross-sectional TEM image of the film surface, the interface between the surface oxide film and the internal Si film has changed from a Si film to a surface oxide layer in several atomic layers, and a good Si oxide film / Si interface is formed. Was done. Observation of a cross-sectional TEM image of a sample in which an oxygen gas was introduced from the gas introduction hole 42 after the film formation and the surface of the Si film was positively oxidized, the interface between the surface oxide film and the internal Si film was similarly determined. In several atomic layers, the film changed from the Si film to the surface oxide layer, and it was found that the film thickness of the surface oxide layer increased. This is the SIMS of a film treated with oxygen gas.
Measurements are consistent with an increase in the result of the SiO ⁺ detection at the surface.
The Si oxide film / Si interface is important for the stability of the electrical characteristics of the semiconductor device, particularly in a metal / oxide / semiconductor (MOS) structure and complementary MOS (CMOS) structure device.
The ideal Si oxide film / Si oxide film having an ideal Si oxide film / Si interface or the ideal Si oxide film / Si film is also effective as a base film for forming an SiO ₂ film thereon by a plasma CVD method. In addition, when an excimer laser, for example, a XeCl excimer laser (wavelength: 308 nm) is irradiated to the amorphous film having a low substrate temperature in Table 1, a high-purity polycrystalline Si film can be formed at a low process temperature.

If nitrogen gas is introduced, plasma 5
With 0, the thin film on the substrate 48 is subjected to a nitriding treatment. Further, by irradiating the substrate 48 with the electron beam 34, the annealing effect can be enhanced. That is, when the electron beam 34 irradiates the substrate 48, the substrate 48 is heated by the electron beam 34, so that the crystallinity of the substrate 48 can be improved. Further, by utilizing the fact that electrons are charged on the substrate 48, positive ions contained in the plasma 50 are
8 and the substrate 48
The electrons charged above can also be neutralized with positive ions. When a high-frequency voltage is applied to the substrate holder 46 and a fluorine-based or chlorine-based compound gas is introduced into the reaction chamber 14 as a gas, a directional etching process can be performed on the substrate 48. According to the present embodiment, the decompression chamber 12 is provided between the electron beam source 10 and the reaction chamber 14, and the electron beam source 10 and the reaction chamber 14 are separated by the decompression chamber 12. The gas pressure in the chamber 14 can be set to an arbitrary gas pressure optimal for the plasma processing. Thereby, low molecular active species are generated by gas decomposition, thereby promoting the chemical reaction and improving the purity of the sample.

(Embodiment 2) Next, a second embodiment of the present invention will be described with reference to FIG. In the present embodiment, an electron beam source 52 based on a microwave system is used instead of the hot filament system shown in FIG.
Therefore, only the configuration of the electron beam source 52 will be described. The electron beam source 52 is configured such that a microwave waveguide 54 is connected to the upper side of the container 16 instead of the cathode 22. Microwaves are introduced into the microwave waveguide 54 from a microwave power supply (not shown). When the microwave is irradiated on the hydrogen gas or the helium gas introduced into the container 16, A plasma is generated in 16.
The plasma is extracted to the decompression chamber 12 as an electron beam by the extraction electrodes 28 and 30. Also in this embodiment, since the plasma can be generated by using the microwave and the electron beam 34 can be extracted from the plasma, the decompression chamber is provided between the electron beam source 52 and the reaction chamber 14 similarly to the above embodiment. By providing 12, the gas pressure in the reaction chamber 14 can be set arbitrarily.

(Embodiment 3) Next, a third embodiment of the present invention will be described with reference to FIG. The plasma processing apparatus according to the present embodiment includes an electron beam source 56, decompression chambers 58 and 60.
The substrate 48 and the substrate holder 46 are arranged in the atmosphere constituting the processing chamber. The electron beam source 56 includes a container 62 for storing a hydrogen gas or a helium gas. A tungsten filament 62 is provided at one end of the container 62, and an electric field lens 66 is provided at the other end of the container 62. In the electron beam source 56, a DC voltage is applied between an anode (not shown) provided on the inner wall of the container 62 and the filament 64, and a hydrogen gas or a helium gas is introduced into the container 62. An electric field lens 66 that generates a single plasma in the container 62 and has the same function as the extraction electrodes 28 and 30
And a single electron beam 68 is extracted from the plasma, and the beam diameter of the electron beam 68 is reduced. The decompression chambers 58 and 60 are configured as rooms for forming an electron beam transmission path for transmitting the electron beam 68. In each of the decompression chambers 58 and 60, magnetic lenses 70 and 72 are concentric with the electric field lens 66, respectively. Are located. Each of the magnetic lenses 70 and 72 is formed of, for example, a solenoid coil, and is configured to apply a magnetic field generated from the solenoid coil to the electron beam 68 so as to reduce the beam diameter of the electron beam 68. And electron beam 6
Numeral 8 is applied to the substrate 48 through the beam passage holes 74 and 76 in a state where the beam diameter is narrowed by the magnetic lenses 70 and 72. The electron beam holes 74, 7
6 is formed by irradiating the partition walls 78, 80 of the decompression chambers 58, 60 with an electron beam 68, respectively. The decompression chambers 58 and 60 are provided with exhaust ports 82 and 8 respectively.
The vacuum pumps are connected to each other via a vacuum pump 4, and the vacuum pumps 58 and 60 are maintained at designated gas pressures by operating the vacuum pumps.

In this embodiment, the gas pressure in the decompression chambers 58 and 60 is successively made lower than the atmospheric pressure, so that the substrate 48
Can be treated in an atmosphere at atmospheric pressure. In this case, since the single electron beam 68 is irradiated on the substrate 48, the processing can be performed over the entire surface of the substrate 48 by moving the substrate 48 in a direction crossing the electron beam 68. Note that, of the region where the substrate 48 is arranged, the region filled with gas or plasma has the same function as the reaction chamber. In the present embodiment, the electron beam 6
Since the substrate 8 is irradiated with 8, the annealing effect can be enhanced. In addition, since the positive ions included in the plasma flow into the substrate 48, the electric charges charged on the substrate 48 can be neutralized, and the charging of the substrate 48 can be prevented. In the present embodiment, the tungsten filament 64 or LaB ₆ (lanthanum) may be heated to generate thermal electrons, and the thermal electrons may be directly extracted to generate the electron beam 68. Further, in the present embodiment, since the two decompression chambers 58 and 60 are provided as decompression chambers, the load on the vacuum pump can be reduced by multi-stage differential evacuation.

(Embodiment 4) Next, a fourth embodiment of the present invention will be described with reference to FIG. In this embodiment, a pulsed electron beam source 86 is used as an electron beam source, and a single or 300 pulsed electron beams 88 are generated from the pulsed electron beam source 86, and on the back side of the substrate 48,
A plurality of permanent magnets 90 are arranged so as to face each other, and a magnetron magnetic field 92 is formed by each of the permanent magnets 90.
4 is confined on the processing surface side (front surface side) of the substrate 48. Pulsed electron beam source 8
6 uses the electron beam source 56 when generating a single pulsed electron beam 88, and
Is generated using the electron beam source 10. In this case, a pulse signal of about 100 to 200 V is periodically applied between the electric field lens or the anode 24 and the cathode 22 to periodically generate a pulse arc discharge. Then, the pulse width and the pulse interval of the pulse signal generator for generating the pulse signal are adjusted by the pulse signal adjusting means of the pulse signal generator. That is, the application time of the pulse signal applied to the electric field lens 66, the anode 24, and the cathode 22 becomes the pulse width of the pulse electron beam 88, and the interval between the application time of one pulse signal and the application time of the next pulse signal is the pulse electron beam. Since the pulse interval of the beam 88 is used, the pulse width of the pulse signal generated from the pulse signal generator and the pulse signal generation interval are adjusted by, for example, the power-on / off timing and the power-on time. The energy of the pulsed electron beam 88 is adjusted by adjusting the voltage of the pulse signal applied to the electric field lens 66 or the anode 24 and the cathode 22. For example, by applying a voltage of about 1 kV between two electrodes, about 1 keV
With this energy, a pulsed electron beam having an output pulsed electron beam amount of 1000 mA can be extracted by 300 pulsed electron beams 88. further,
The gas flow rate when gas flows into the reaction chamber 14 is adjusted by a needle valve (not shown),
By adjusting the degree of opening and closing of a gate valve (not shown) provided in an exhaust system that discharges gas in the reaction chamber 1,
Adjust the gas pressure in 4. In the present embodiment, the pressure in the reaction chamber 14 can be reduced below the atmospheric pressure, and the plasma density on the surface of the substrate 48 can be increased by the magnetron magnetic field 92 to reduce charging by the pulsed electron beam 88. In this embodiment, the energy of the pulsed electron beam 88, the pulse width, and the pulse interval are adjusted, and the gas pressure in the reaction chamber 14 is adjusted to include the charge amount of the substrate 48 and the plasma in the reaction chamber 14. Since the potential of the substrate 48 can be controlled by adjusting the amount of neutralization of the positive ions flowing into the substrate 48,
Irradiation with the pulsed electron beam 88 on the surface of the substrate 8 causes charging, and it is possible to prevent the occurrence of discharge breakdown due to the charging. In each of the above embodiments, the case where the reaction chamber and the decompression chamber are provided has been described.
Can be in the same room.

(Embodiment 5) FIG. 5 is an equivalent circuit of an entire display device in which a peripheral driving circuit and a TFT active matrix are integrated on the same substrate using the Si films produced by the methods of Embodiments 1 to 6. . Pixel unit 150 and TFT 151
And a vertical scanning circuit 153 for driving the video signal, a horizontal scanning circuit 154 for dividing a video signal for one scanning line into a plurality of blocks and supplying them in a time-division manner, and a data signal line Vdr1 for supplying a video signal Data. , Vdg1, Vdb1,..., A switch matrix circuit 155 for supplying a video signal to the pixel unit for each divided block, a gate wiring 156, and a drain wiring 157. FIGS. 6 and 7 show the TF of the present embodiment.
2A and 2B are a plan view and a sectional view of a unit pixel of a T active matrix section. The cross-sectional structure taken along the dotted line AA 'in FIG. 13 corresponds to FIG. The active matrix includes a gate wiring 156 formed on a glass substrate, a drain electrode 157 formed to intersect the gate wiring 156, a TFT 151 formed near an intersection of these electrodes,
The pixel electrode 16 connected to the source electrode 158 of the FT via the contact hole 160 provided in the protective insulating film 159
And 1. The other end of the pixel electrode 161 is connected to the capacitor electrode 1 through a contact hole 160 provided in the protective insulating film.
The capacitor electrode 162 forms an additional capacitance with the adjacent gate electrode 86. AA 'cross section is from the bottom, from the bottom, a glass substrate 168, a buffer layer 169, an intrinsic semiconductor layer 100, a low-resistance n-type semiconductor layer 102, a high-resistance n-type semiconductor layer 103, a gate insulating film 104, a through-hole portion 105, and a source electrode. 158, a drain wiring 157, an interlayer insulating film 106, a contact hole 160, a first gate electrode 107, and a second gate electrode 108. FIG. 8 shows a CMOS thin film transistor (TF) to which a Si film formed in the process of the present invention is applied, which is used for a driving circuit of a liquid crystal display device.
It is sectional drawing of T). In the figure, the left side shows the n-type TFT of the CMOS peripheral driving circuit, and the right side shows the p-type TFT used in the CMOS driving circuit. The TFT is formed on a buffer insulating film 111 formed on a glass substrate 110. The buffer layer 111 is an SiO ₂ film, and the glass substrate 110
It has the role of preventing diffusion of impurities from the surface. An intrinsic polycrystalline Si (poly-Si) film 120 is formed on the buffer insulating film 111, and a pair of high-resistance n-type poly-Si layers 121 and a pair of high-resistance p-type poly are formed on the intrinsic poly-Si film 120.
-Si layer 122 is in contact. Further, each of the pair of high-resistance poly-Si layers 121 and 122 has a low-resistance n-type layer.
The type poly-Si layer 123 and the p-type poly-Si layer 124 are in contact. On top of these series of poly-Si layers is SiO
_A first gate line 126 made of Al is formed via a gate insulating film 125 made of 2, and a second gate electrode 127 made of Nb is formed so as to cover the first gate line. I have. An interlayer insulating film 128 made of SiO ₂ is formed so as to cover all the members,
The drain electrode and the source electrode 130 are connected to the low-resistance n-type poly-S through a contact hole provided in the interlayer insulating film.
i layer 123. The entire device is covered with a protective insulating film 131 made of Si ₃ N ₄ . The pair of high resistance poly-Si layers 121 or 122 is a first
Is formed in a self-aligned manner with respect to the pattern of the gate wiring 126. That is, the intrinsic poly-Si layer 120 and the high resistance
The boundary of the poly-Si layer 121 or 122 coincides with the position of the pattern end of the first gate electrode 126. Also, a part of the second gate electrode 127 and the high resistance po
Some of the ly-Si layers 121 and 122 overlap with a gate insulating film interposed therebetween. As described above, a part of the gate electrode and a part of the high-resistance poly-Si layers 121 and 121 are overlapped to form a high-resistance poly-Si layer 121.
By reducing the resistance of the ly-Si layers 121 and 122 by the gate electrode, the high-resistance poly-Si layers 121 and 1 are reduced.
22 reduces the lateral electric field and improves the reliability of the device. Further, in this embodiment, since Al having a low resistance is used for the first gate electrode 126, a signal delay caused by wiring resistance can be reduced, and a large-area and high-definition display device can be achieved. Furthermore, by coating Al with Nb, which is a high melting point metal, hillock growth of Al due to the heat treatment step can be suppressed, so that there is an effect that short circuit failure with the upper wiring can be prevented. In this embodiment, a high-purity Si film and a silicon oxide film formed by the methods shown in the first to fourth embodiments are used. The field effect mobility, flat band voltage, and threshold voltage, which are basic characteristics of the TFT, were obtained. The field-effect mobility reflects the crystallinity of intrinsic silicon, and is preferably as large as possible. The flat-band voltage is preferably as small as possible in relation to the fixed charge amount due to impurities in the insulating film, and the threshold voltage is as low as the operating voltage of the transistor. The field-effect mobility, the flat band voltage, and the threshold voltage were 272 cm ^{2 /} Vs, 1.2 V, and 0.8 V, respectively, indicating that very good device characteristics were obtained by the high-purity film. . FIG. 9 is a cross-sectional view of another example of a CMOS thin film transistor (TFT) to which a Si film formed in the process of the present invention is applied, which is used for a driving circuit of a liquid crystal display device. This embodiment has substantially the same configuration as the first embodiment, except that the second gate electrode 127 is formed only on the side surface of the first gate electrode 126 and the first gate electrode 126 is in contact with the first side. Different from the embodiment. In this embodiment, Nb is used for the first gate electrode and Nb is used for the second gate electrode.
bN was used. Such formation of the electrodes only on the side surfaces is achieved by forming NbN on the entire surface of the substrate and then etching the NbN by reactive ion etching having a strong anisotropy. Functionally, the point that the second gate electrode 127 is connected to the first gate electrode 126 is the same as in the first embodiment.
This has the effect of reducing the lateral electric field in the Si layers 121 and 122 and improving the reliability of the device. Further, in the structure of this embodiment, a photoresist forming step for processing the second gate electrode 127 is unnecessary. Impurities such as alkali metals are TF
Although the T characteristics are adversely affected, particularly in the manufacture of a liquid crystal display device, since the glass substrate is large, impurities adhered to the substrate surface easily diffuse into the element portion due to insufficient cleaning of the substrate or the like.
The density of the silicon oxide film is about 2.3, while the density of the silicon nitride film is about 3.0. If this dense silicon nitride film is used as an underlayer, diffusion of impurities from the glass substrate can be prevented. Can be prevented. The underlayer may be composed of a single layer of a silicon nitride film, a silicon oxide film upper layer / a silicon nitride film lower layer, a silicon nitride film upper layer / a silicon oxide film lower layer, and a silicon nitride film upper layer / a silicon oxide film intermediate layer / a silicon nitride film lower layer. 10 and 11 show the upper layer 2 of the silicon nitride film, respectively.
FIG. 2 is a cross section of the element in the case of 00 / silicon oxide film lower layer 201, silicon nitride film upper layer 202 / silicon oxide film intermediate layer 203 / silicon nitride film lower layer 204. As described above, these films are composed of high-purity films, and have a multilayer structure with good interfaces.

[0026]

As described above, according to the thin film processing step of the present invention, since the electron beam source and the processing chamber are separated by the separation means or the decompression chamber, the reaction chamber in which the processing gas exists is present. Can be set to an arbitrary gas pressure that is optimal for the plasma treatment, and a low molecular active species is generated by gas decomposition to promote a chemical reaction, thereby improving the purity of the sample. In addition, the potential of the sample can be controlled by adjusting the charge amount of the sample due to the electron beam irradiation and adjusting the neutralization amount due to the inflow of positive ions contained in the plasma in the processing chamber into the sample, It is possible to prevent the occurrence of charge caused by the electron beam on the surface of the sample and the occurrence of discharge breakdown beforehand.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a thin film processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part of an electron beam source according to a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a plasma processing apparatus according to a third embodiment of the present invention.

FIG. 4 is a schematic diagram of a main part showing a fourth embodiment of the present invention.

FIG. 5 is an overall configuration diagram of a liquid crystal display device.

FIG. 6 is a plan view of a pixel of a liquid crystal display device.

FIG. 7 is a cross-sectional view of a pixel of a liquid crystal display device.

FIG. 8 is a schematic cross-sectional view of a thin film transistor used for a liquid crystal display device.

FIG. 9 is a schematic cross-sectional view of a thin film transistor used for a liquid crystal display device.

FIG. 10 is a schematic cross-sectional view of a thin film transistor used for a liquid crystal display device.

FIG. 11 is a schematic cross-sectional view of a thin film transistor used for a liquid crystal display device.

[Explanation of symbols]

Reference Signs List 10: beam source, 12, 58, 60: decompression chamber, 14: reaction chamber, 16: container, 18: gas inlet, 22: cathode, 24: anode, 26, 90: permanent magnet, 28, 3
0: extraction electrode, 34: electron beam, 40: passage hole, 46
... substrate holder, 48 ... substrate, 50 ... plasma, 52, 5
6 electron beam source, 54 microwave waveguide, 66 electric field lens, 70, 72 magnetic field lens, 86 pulse electron beam source, 88 pulse electron beam, 89 pulse electron beam container, 91 magnetron magnetic field, 92: secondary electron beam, 93: Si ion, 94: gas supply, 95: gas supply container, 100: intrinsic semiconductor layer, 102: low resistance n
Semiconductor layer, 103... High-resistance n-type semiconductor layer, 104, 1
25: gate insulating film, 105: through hole portion, 106
... Interlayer insulating film, 107 first gate electrode, 108 second gate electrode, 110 glass substrate, 111 buffer insulating film, 120 intrinsic polycrystalline Si (poly-Si) film,
121: High resistance n-type poly-Si layer, 122: High resistance p-type
poly-Si layer, 123... low-resistance n-type poly-Si layer, 12
4: low resistance p-type poly-Si layer; 126: first gate wiring; 127: second gate electrode; 128: interlayer insulating film;
130: drain electrode and source electrode, 131: protective insulating film, 150: pixel portion, 151: TFT, 153: vertical scanning circuit, 154: horizontal scanning circuit, 155: switch matrix circuit, 156: gate wiring, 157: drain wiring 158, source electrode, 159, protective insulating film, 1
60 contact hole, 161 pixel electrode, 162
Capacitance electrode, 168: glass substrate, 169: buffer layer,
200, 202: upper layer of silicon nitride film, 201: lower layer of silicon oxide film, 203: intermediate layer of silicon oxide film, 204
... Lower layer of silicon nitride film.

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 2H092 JA24 JA37 MA08 MA15 MA19 PA01 5F045 AA08 AB02 AB32 AC01 AC02 AC03 AC04 AC05 AC08 AC09 AC17 BB16 DP04 EH04 EH06 EH16 EH19 5F110 AA01 AA03 AA08 AA26 BB02 BB04 DD02 DD03 DD02 EE04 EE14 FF02 GG02 GG13 GG35 HM17 HM18 NN03 NN23 NN24 PP03 PP04 QQ11

Claims (12)

[Claims] A reaction chamber for generating an electron beam having an electron beam source, containing a gas together with a sample, and irradiating a sample on a substrate with plasma generated by ionization of the gas by introduction of the electron beam. The electron beam is transmitted by an electron beam transmission path that is disposed between the electron beam source and the reaction chamber, separates the two, and guides the electron beam from the electron beam source to the reaction chamber. And a thin film processing step. 2. The method according to claim 1, wherein the gas is at least SiF ₄ , SiC
l ₄ , SiH ₄ , MgCl ₃ , MgBr ₃ , AlC
l ₃ , PCl ₃ , PBr ₃ , PH ₃ , TiCl ₄ , Cr
Cl ₃ , CuCl ₂ , CCl ₄ , Cu ₂ Cl ₂ , GeCl
₄ , AsCl ₃ , AsH ₃ , ZrF ₃ , AgCl, Ag
Br, InCl ₃ , InBr ₃ , SnCl ₄ , NdCl ₃ ,
LaCl ₃ , CeCl ₃ , PrCl ₃ , SmCl ₃ , S
mCl ₂ , EuCl ₃ , EuCl ₂ , GdCl ₃ , TbC
l ₃ , DyCl ₃ , HoCl ₃ , ErCl ₃ , TmCl
₃ , YbCl ₃ , LuCl ₃ , CO ₂ , B ₂ H ₆ , GeH
_{4, SiI 4, AsO 3,} Si 3 N 4, CH 4, O 2, N
_{2, N 2 O, Si (} OCH 3) 3, Si 2 H 6, Si (OC 2 H 5)
₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) ₄ , Si ₃ H ₈ , S
iBr ₄ , SiF (OC ₂ H ₅ ) ₃ , SiH ₂ F ₂ , SiH ₂ C
A thin film processing method including any one of l ₂ , SiHCl ₃ , and SiI ₄ . 3. A reaction chamber for generating an electron beam having an electron beam source, a reaction chamber for accommodating a gas together with the sample, and irradiating the sample on the substrate with plasma generated by ionization of the gas by introduction of the electron beam. And a step of introducing an electron beam having a decompression chamber, which is a space part having a lower pressure than the gas pressure of the reaction chamber, disposed between the electron beam source and the reaction chamber, to the reaction chamber. Thin film processing method. 4. A process for generating an electron beam having an electron beam source, a reaction chamber for accommodating a gas together with a sample, and irradiating a sample on a substrate with plasma generated by ionization of the gas by introduction of the electron beam. And heating the sample by irradiating the sample with the electron beam, and a space disposed between the electron beam source and the reaction chamber and having a lower pressure than a gas pressure of the reaction chamber. Introducing an electron beam having a reduced pressure chamber into the reaction chamber. 5. The step of generating an electron beam includes an electric field lens for narrowing a beam diameter of the electron beam, wherein the electric field lens generates a single electron beam, and the electric field lens is provided in the decompression chamber. 5. The thin film processing method according to claim 1, further comprising a magnetic field lens for narrowing a beam diameter of the electron beam passing through the thin film. 6. The step of generating an electron beam includes an electric field lens for narrowing a beam diameter of the electron beam, wherein the electric field lens generates a single electron beam, and includes a plurality of the decompression chambers. The decompression chambers are arranged adjacent to each other, and a magnetic lens for narrowing the beam diameter of the electron beam passing through the electric field lens or the electron beam passing through another decompression chamber is arranged in each decompression chamber. The method for processing a thin film according to claim 1, wherein: 7. A charge amount adjusting step of adjusting a charge amount of the sample on the substrate accompanying the irradiation of the electron beam, and a step of flowing positive ions contained in plasma in the processing chamber into the sample on the substrate. 7. The thin film processing method according to claim 1, comprising a step of adjusting the amount of neutralization to adjust the amount of neutralization. 8. The step of generating an electron beam includes the steps of: introducing and storing a gas; and generating an arc discharge in the container in response to a pulse signal and emitting thermoelectrons in the container. A pulse signal adjusting step of adjusting a pulse width and a pulse interval of a pulse signal applied between a pair of electrodes for generating plasma, and applying a voltage to a plurality of extraction electrodes for extracting an electron beam from the container by applying a voltage. Adjusting the gas pressure for adjusting the gas pressure of the reaction chamber, comprising the step of adjusting the voltage of the reaction chamber.
7. The method for treating a thin film according to any one of 6. 9. The reaction step in the reaction chamber, wherein a step of forming a magnetic field around the sample and confining plasma in the reaction chamber to a surface to be processed of the sample is provided. 9. The method for treating a thin film according to any one of items 1 to 8. 10. The thin film processing method according to claim 1, wherein the step of processing the sample on the substrate is performed in a chamber whose inner wall is coated with Si. 11. A pair of substrates, at least one of which is transparent;
A liquid crystal display device comprising: a liquid crystal layer sandwiched between the substrates; and a plurality of semiconductor elements using a silicon film and a silicon oxide film arranged in a matrix on one of the pair of substrates. 11. A liquid crystal display device, wherein at least one of the film and the silicon oxide film is a silicon film or a silicon oxide film manufactured in the steps of claims 1 to 10. 12. The liquid crystal display device according to claim 11, wherein said silicon film or silicon oxide film is used.