JP3230315B2 - Processing method using dielectric barrier discharge lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing method using electric discharge, for example, a film forming apparatus using a so-called chemical vapor deposition method in which a process gas is decomposed and deposited by electric discharge,
The present invention relates to improvement of various processing methods such as etching by electric discharge.

[0002]

2. Description of the Related Art As a technique related to the present invention, for example, "Applied Physics" Vol.
On page 9, a method for forming an amorphous silicon thin film by a chemical vapor deposition method (hereinafter abbreviated as CVD) using high-voltage pulse discharge is described. Japanese Unexamined Patent Publication No. 3-212283 discloses a dielectric barrier discharge (also known as an ozonizer discharge or silent discharge. See the revised Electric Discharge Handbook, published by the Institute of Electrical Engineers of Japan, reprinted 7th edition, June 1991, page 263). Discloses an apparatus for producing a thin film by a CVD method using ultraviolet rays radiated from a lamp. The treatment method using discharge or light as described above is useful because thin films for solar cells and various semiconductor elements can be formed with high quality.

[0003] However, when electric discharge is used, there is a feature that the processing speed is high. However, impurities from the metal electrode for generating electric discharge contaminate the object to be processed or the decomposition of the processing fluid by the decomposition. The resulting product adheres to the electrodes, causing a non-uniform discharge, which results in a non-uniform process. In particular, it has been difficult to uniformly treat a large-area workpiece. Further, in general, in the case of processing using light, there is a problem that the processing speed is not always sufficient. Further, in general, in the above-described processing method, discharge or light mainly acts on a process gas, which is a processing fluid, to activate, decompose, ionize, or synthesize the gas. It does not act directly on the substrate that is the object. Even if a part of the discharge plasma contacts the object or is irradiated with light that is not absorbed by the processing fluid, the amount is very small, and the discharge or the light source Since the characteristics, ie, the pressure of the processing fluid, the type of discharge, the discharge power or the wavelength and intensity of the light, are not set so as to be optimal for the processing of the processing fluid, the effect of the discharge plasma and light on the object to be irradiated. Is less. Therefore, in a state in which the processing fluid is ionized, dissociated, and activated using a discharge device or a light source in a state where the processing object is in contact with the processing fluid, the processing is incomplete, or There is a problem that the processing speed or processing efficiency is not always sufficient. In addition, since the conventional arc discharge lamp has radiation over a wide wavelength range, light having a wavelength that is rather detrimental to processing is also irradiated at the same time, so that the discharge device and the conventional arc discharge lamp can be used. Even when combined, the improvement was not always enough.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a processing method using a dielectric barrier discharge lamp capable of performing various kinds of processing with high quality and at high speed or with high efficiency. It is to be.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an object to be processed, a processing fluid , a discharge device for ionizing, dissociating, and activating the processing fluid, and a dielectric in which a discharge gas is sealed.
And a body barrier discharge lamp , wherein at least the object is irradiated with radiation from the dielectric barrier discharge lamp at the same time as the discharge treatment of the processing fluid. This is achieved by employing a processing method using a dielectric barrier discharge lamp characterized in that:

[0006] Further, the dielectric barrier discharge lamp may include n
wavelength range 180 to 200, 165 to 190, 240 to 255, 200 to 240, 120 expressed in m units
The above object can be further attained by adopting a processing method using a dielectric barrier discharge lamp characterized by having radiation light in at least one wavelength range from 300 to 190 and 300 to 320.

Further, the discharge device is a dielectric barrier discharge device, and at least a part of the dielectric of the dielectric barrier discharge device, in particular, a surface of the device facing the discharge space is contained in the workpiece. The object of the present invention is further achieved by constituting the element, preferably an oxide or nitride of the main element.

[0008]

[Actions of the Means] The object to be treated , the processing fluid ,
A discharge device for ionizing, dissociating and activating the processing fluid, and a dielectric barrier discharge lamp filled with a discharge gas
And a processing method for processing an object to be processed having a processing chamber containing the same, wherein at least the object to be processed is irradiated with radiation from a dielectric barrier discharge lamp simultaneously with the discharge treatment of the processing fluid, Since the object to be processed is also activated by the light from the barrier discharge lamp in addition to the processing fluid, the dielectric barrier discharge lamp emits light with high efficiency monochromatically in a narrow wavelength region. It has features that are not found in conventional arc discharge lamps, such as changing the light output without changing the spectral distribution by changing the input power to the lamp. It is possible to irradiate with high efficiency light having a characteristic spectral distribution that cannot be performed, so that high-efficiency, high-speed, and high-quality processing can be performed.

Further, the dielectric barrier discharge lamp is provided in a processing chamber containing the processing object and the processing fluid .
Therefore , the absorption by the window member between the processing chamber and the dielectric barrier discharge lamp is eliminated, and the distance between the object to be processed and the dielectric barrier discharge lamp can be shortened, so that irradiation can be performed with high efficiency. Therefore, high-efficiency, high-speed, and high-quality processing can be performed with a small device. In addition, since the light source provided in the processing chamber is a dielectric barrier discharge lamp, the dielectric barrier discharge lamp has a large degree of freedom in shape, and has a light output characteristic due to a temperature change of the tube wall, particularly a change in spectral distribution. It has features that can not be solved when a light source is installed in a processing chamber, such as the absence of a light source and low tube wall temperature. , High-speed, high-quality processing becomes possible.

[0010]

When the dielectric barrier discharge lamp has an airtight discharge space and emits ultraviolet light through a light extraction window member that transmits ultraviolet light, the wavelength range expressed in nm is 180 to 200 and 165 to 190. , 240-2
55, 200 to 240, 120 to 190, and 3
By emitting ultraviolet rays in the wavelength range from 00 to 320, a high-efficiency and high-quality processing method is achieved. Because the ultraviolet light in the above-mentioned wavelength range is at least as a main luminescent gas, by using a mixed gas of argon and fluorine, argon and chlorine, krypton and fluorine, krypton and chlorine, xenon, and xenon and chlorine. It is possible to emit light by excimer molecules of each mixed gas, but by using these gases,
This is because a state in which the emission gas is less deteriorated and the light extraction window member is less deteriorated can be realized.

[0012]

The following effects can be obtained by constituting the discharge device with a dielectric barrier discharge device. That is,
First, since high-energy electrons can be obtained in the discharge plasma generated by the dielectric barrier discharge, various processing fluids can be efficiently ionized, dissociated, and activated, so that processing can be performed at an extremely high speed. Furthermore, even when a plurality of different types of processing fluids are mixed and used, electrons having a higher energy than normal discharge such as glow discharge can be obtained, so that only one type of processing fluid is ionized, dissociated, and activated. Since all of the used processing fluids are dissociated and activated without being converted, high-efficiency, high-speed, high-quality processing can be performed. Second, in a dielectric barrier discharge device, a plurality of rod-shaped or cylindrical electrodes are arranged in parallel, so that a large-area uniform discharge plasma can be easily generated. Can be processed. Third,
In the dielectric barrier discharge device, the metal electrode is not directly exposed to the discharge space, and a chemically stable dielectric such as quartz glass, alumina, or silicon nitride is in contact with the discharge space in the device, The contamination of impurities from the electrodes is small, and high quality processing can be obtained.

Further, at least a part of the dielectric material of the dielectric barrier discharge device, particularly the surface of the device facing the discharge space in the device, may contain an element contained in the object to be processed, preferably an oxide of the main component element or By using a nitride, even if the dielectric is slightly scattered, substantial contamination of the film is reduced, so that high quality processing can be obtained. For example, when a thin film of hydrogenated amorphous silicon is formed on a silicon wafer, a high quality film can be obtained by using silicon oxide, that is, quartz glass as a dielectric.

In the dielectric barrier discharge device, the energy of the electrons of the discharge plasma can be changed by changing the distance between the pair of electrodes performing the discharge, that is, the size of the discharge gap formed by the dielectric. Therefore, by adjusting the distance between the electrodes in accordance with the type of the processing fluid to be used and setting the optimum conditions, higher quality and uniform processing can be achieved. In addition, depending on the processing fluid, decomposition products of the processing fluid adhere to the dielectric, and the substantial interelectrode distance changes, resulting in the resulting film being non-uniform. By adjusting the distance between the electrodes in accordance with the amount of decomposition products attached to the body, higher quality and uniform processing can be achieved.

In the above-mentioned dielectric barrier discharge device, the discharge gap formed by the dielectric is set to 1 mm to 1 mm.
Make it a narrow value of 0 mm. With the above configuration, the temperature of the processing fluid passing between the dielectrics can be adjusted by changing the temperature of the dielectric. By adjusting the temperature of the dielectric in accordance with the type of the processing fluid and the type of the object to be processed and optimizing the temperature of the processing fluid, higher quality and uniform processing can be achieved.

[0017]

FIG. 1 is a schematic view of a film forming method according to a first embodiment of the present invention. Process gas supply port 4, which is a processing fluid,
In a reaction vessel 3 having a vacuum exhaust port 5, an electrode group 1 is provided on the side close to the process gas supply port 4, and an electrode group 2 is provided downstream of the electrode group 1 with respect to the process gas. Individual electrodes 1a, 1b, 1c, 2a, 2b, 2 constituting an electrode group
The structures c and 2d are structures in which a hollow cylinder 11 made of metal is covered with a dielectric 12 as shown in the longitudinal sectional view of FIG.
In this example, the metal hollow cylinder 11 is made of stainless steel, the outer diameter is 6 mm, the inner diameter is 4 mm, the dielectric 12 is quartz glass with a wall pressure of 1 mm, and the length is 300 mm. By flowing air, water, liquid nitrogen or the like through the hollow portion 13 of the metal hollow cylinder 11, the temperature of the electrode can be adjusted,
Therefore, the temperature of the process gas can be adjusted.

As shown in FIG. 3, the electrode group 1 includes a plurality of electrodes 1a, 1b,
And is mechanically fixed, and is configured as an integral structure. The electrode group 2 is also integrated with a similar structure. Further, the electrode group 1 or the electrode group 2 is fixed to the reaction vessel 3 by a usual means for moving the electrode group 1 by a maximum of 10 mm with an accuracy of 0.1 mm, for example, using a screw feeder. That is, the distance t between the electrode group 1 and the electrode group 2 can be adjusted over a maximum of 10 mm with an accuracy of 0.1 mm in the reaction vessel while performing discharge if necessary. The individual electrodes of the electrode group 1 and the electrode group 2 are electrically connected to each other, and are connected to the AC power supply 8. Reaction vessel 3
Inside, the substrate 6 which is a processing object is placed on the support 7 after the process gas has passed through the gap between the electrode groups 1 and 2, that is, downstream of the electrode group with respect to the process gas. The support 7 has a normal means for adjusting the temperature of the substrate 6, that is, a means for heating by electric heating or a means for cooling with water.

Dielectric barrier discharge lamps 9 a and 9 b for radiating ultraviolet rays are provided between the electrode group 2 and the substrate 6 in the reaction vessel 3. FIG. 4 is a schematic view of the coaxial cylindrical dielectric barrier discharge lamp used in the first embodiment. The discharge vessel 41 is made of quartz glass and has a hollow cylindrical shape with the inner tube 14 and the outer tube 15 arranged coaxially. The inner tube 42 and the outer tube 43 also serve as a dielectric barrier for a dielectric barrier discharge and a light extraction window member, and electrodes 44 and 45 made of a metal mesh that transmits light are provided on the outer surfaces thereof. A ring-shaped getter 46 is provided at one end of the discharge vessel 41. The discharge space 47 is filled with a discharge gas for forming excimer molecules by a dielectric barrier discharge.
A transparent electrode 4 made of a metal net provided on the surface of each of 2, 43
When a voltage is applied to AC power supply 4 and 45 by AC power supply 48, a so-called dielectric barrier discharge, also known as an ozonizer discharge or a silent discharge, is generated in discharge space 47, and dielectrics 42 and 4 are generated.
3. Ultraviolet rays are radiated with high efficiency through the transparent electrodes 44 and 45. Although not shown in the figure, the surfaces of the transparent electrodes 44 and 45 are covered with an ultraviolet-permeable resin, glass, or the like, as required, to be electrically insulated. Further, it is desirable that the outer electrode 45 that is in direct contact with the processing fluid is used at the ground potential.

The dielectric barrier discharge lamps 9a and 9b are filled with xenon gas as a main component of the luminescent gas.
120 to 190 nm with a maximum around 172 nm
Emits ultraviolet light in the wavelength range of In the film forming method characterized in that the dielectric barrier discharge lamp as described above is used, the distance between the shortest electrodes determined by the fixed positions of the electrode groups 1 and 2, that is, the length of the discharge gap is set to 3 mm, and the substrate 6 is formed. Using a silicon wafer, a one-to-one mixed gas of monosilane and methane as a process gas, applying an AC voltage to the electrode groups 1 and 2 to generate a dielectric barrier discharge between the electrode groups 1 and 2 Discharge treatment of those gases,
When a thin film of hydrogenated amorphous silicon carbide was formed, a high-efficiency, high-speed, and high-quality thin film was obtained with a small device.

In the second embodiment of the present invention, electrodes having a structure in which a thin film of silicon carbide is provided on the surface of quartz glass which is a dielectric of the electrodes of the first embodiment are used as the electrode groups 1 and 2. The process gas was cooled by using and cooling the electrode by flowing liquid nitrogen through the hollow portion 13 of the electrode. As a result, contamination with impurities was further reduced, and a higher quality thin film was obtained. Depending on the composition ratio of the process gas and the temperature of the electrode, the decomposition product of the process gas adheres to the surface of the electrode, so that the distance between the electrode groups 1 and 2 and, accordingly, the discharge gap of the dielectric barrier discharge is reduced. In some cases, the energy of the discharge plasma was reduced and the properties of the film changed, but a good quality film could be formed by controlling the distance between the electrode groups 1 and 2.

In the third embodiment of the present invention, a mixed gas of krypton and chlorine is sealed as a main component of the luminous gas of the dielectric barrier discharge lamps 9a and 9b, and a maximum value of about 200 to 240 nm is reached at about 222 nm. When the ultraviolet light in the wavelength range was emitted, a good quality film was obtained without damaging the substrate because the energy of photons irradiating the substrate was relatively small.

FIG. 5 is a schematic view of a film forming method according to a fourth embodiment of the present invention. In a reaction vessel 3 having a process gas supply port 4 and a vacuum exhaust port 5 as a processing fluid, a cathode 51 is provided on the side close to the process gas supply port 4 and an anode is provided downstream of the cathode 51 for the process gas. 52 is provided and electrically connected to a DC power supply 53. The anode 52 also serves as a support for the substrate 6 as an object to be processed, and has ordinary means for adjusting the temperature of the substrate 6, that is, heating by electric heating or water cooling.

A coaxial cylindrical dielectric barrier discharge lamp 9a, 9b, 9 having a structure similar to that used in the first embodiment.
c and 9 d are provided between the cathode 51 and the substrate 6 in the reaction vessel 3. Dielectric barrier discharge lamps 9a, 9b, 9
In x and 9d, xenon gas is sealed as a main component of the luminescent gas, and 120 has a maximum value near 172 nm.
And emits ultraviolet light in a wavelength range of 190 nm. In a film forming method characterized by using a dielectric barrier discharge lamp as described above, a silicon wafer is used as a substrate 6, and a one-to-one mixed gas 54 of monosilane and methane is used as a process gas, A direct current glow discharge is generated between the cathode 51 and the anode 52 to discharge the gases, and the gas is discharged from the dielectric barrier discharge lamps 9a, 9b, 9c, and 9d.
When a thin film of hydrogenated amorphous silicon carbide was formed by simultaneously irradiating ultraviolet rays in the wavelength range of nm, a thin film of high efficiency, high speed and good quality was obtained with a small device.

FIG. 6 is a schematic diagram of an incineration method according to a fourth embodiment of the present invention. In the incineration duct 60, the same dielectric barrier discharge electrodes 1a, 1b and 2a as in FIG. 2 are provided and connected to the AC power supply 8. Dielectric barrier discharge lamps 62a, 62b, 62c, and 62d are provided in proximity to a silicon wafer 63 coated with a photoresist as a processing target. The dielectric barrier discharge lamps 62a,
The luminescent material is selected so that 62b, 62c, and 62d emit ultraviolet rays having relatively long wavelengths in the range of 240 to 255 nm and 200 to 240 nm. The processing fluid oxygen 64 injected from the processing fluid supply port 4 is
The dielectric barrier discharge between the dielectric barrier discharge electrodes 1a, 1b and 2a provided in the element 0 converts the oxygen into very active oxygen atoms and ozone. Further, ozone is decomposed into active oxygen atoms and oxygen molecules by ultraviolet rays emitted from the dielectric barrier discharge lamp. When the photoresist, which is an object to be processed, is irradiated with ultraviolet rays radiated from a dielectric barrier discharge lamp in a state of being in contact with the mixture of active oxygen atoms, ozone, and oxygen molecules described above, the substrate, which is an object to be processed, Active oxygen atoms are generated at a high density near the surface of the applied photoresist due to the decomposition of ozone, and ultraviolet rays directly act on the photoresist, so that the photoresist is ashed at a high speed. Since the wavelength of the ultraviolet light emitted from the dielectric barrier discharge lamp is relatively long, there is an advantage that the energy of photons irradiated on the photoresist is small, and as a result, the silicon wafer as a substrate is less damaged.

The ultraviolet light radiated from the dielectric barrier discharge lamp is converted to light having a relatively short wavelength of 180 to 200 nm, 160
When the light-emitting substance is selected so as to emit ultraviolet rays in the range of 120 to 190 nm and 120 to 190 nm, the photoresist which is hardly ashed due to ion implantation also ashes because the photon energy irradiated to the photoresist is large. This has the advantage of being able to

FIG. 7 is a schematic view of an etching method according to a fifth embodiment. In the processing duct 60, the same dielectric barrier discharge electrodes 1a, 1b and 2a as in FIG. 2 are provided.
It is connected to an AC power supply 8. Dielectric barrier discharge lamps 62a and 62b are provided in proximity to a silicon substrate 72 masked by a silicon oxide 71 to be processed. In addition, 73 is a conveyor. Processing fluid supply port 4
The processing fluid chlorine 74 injected from the processing duct 60
And dielectric barrier discharge electrodes 1a, 1b and 2 provided therein.
is converted to highly active active chlorine atoms by a dielectric barrier discharge between the active chlorine atoms. This active chlorine atom is sprayed on the silicon substrate 72 masked with the silicon oxide 71, and reacts with the silicon substrate under irradiation of ultraviolet rays from the dielectric barrier discharge lamp to generate silicon chloride. Etch. The relatively long wavelength ultraviolet light from the dielectric barrier discharge lamp acts directly on the silicon substrate, thereby enabling anisotropic etching.

FIG. 8 is a schematic diagram of a surface modification method according to a sixth embodiment. A plastic film 83 as an object to be processed is provided in close contact with the plate-shaped metal electrode 81, and the metal electrode 82 is provided so as to sandwich the plastic film 83 in cooperation with the metal electrode 81. The processing fluid is air at atmospheric pressure in a stationary state, and the metal electrodes 81 and 82
The space between the two forms a processing chamber, and 84 corresponds to the processing space. 30 near the plastic film 83
Dielectric barrier discharge lamps 62a, 62b having radiation in the wavelength range from 0 to 320 are provided. When a corona discharge is generated between the metal electrodes 81 and 82 by a power supply 85 to generate ozone, active oxygen, and the like from oxygen in the air, and at the same time, the dielectric barrier discharge lamps 62a and 62b irradiate the plastic film 83, and Of the molecule existing at the surface is cleaved, and a -C00H group, -OH
A group is formed. By the above-described treatment, printing, bonding, and the like on the plastic surface can be performed with high quality. Since the wavelength of the ultraviolet light radiated from the dielectric barrier discharge lamp is relatively long, there is an advantage that there is no damage to the object such as decomposition of the plastic trunk polymer as the object. Further, in this embodiment, since the object to be processed is in an atmosphere higher than the atmospheric pressure, there is an advantage that the movement of the object to be processed is simple.

[0029]

As described above, according to the present invention,
A processing method capable of performing various kinds of processing with high quality, high efficiency, and at a sufficient speed can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a film forming method using the present invention.

FIG. 2 is an explanatory view of a dielectric barrier discharge electrode used in the present invention.

FIG. 3 is an explanatory view of an electrode fixing structure.

FIG. 4 is an explanatory view of a dielectric barrier discharge lamp used in the present invention.

FIG. 5 is an explanatory view of another film forming method using the present invention.

FIG. 6 is an explanatory diagram of a method for ashing a photoresist using the present invention.

FIG. 7 is an explanatory diagram of a method for etching a silicon substrate using the present invention.

FIG. 8 is an explanatory view of a plastic surface modification method using the present invention.

[Explanation of symbols]

Reference numerals 1 and 2 include a dielectric barrier discharge electrode group 3 a reaction vessel 4 a process gas supply port 5 a vacuum exhaust port 6 a substrate 7 a support 8 an AC power supply 9 a and 9 b a dielectric barrier discharge lamp 11 a hollow cylinder 12 a dielectric 13 a hollow part 21 and a fixing member.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-299324 (JP, A) JP-A-4-80372 (JP, A) Patent 2537304 (JP, B2) Patent 2650050 (JP, B2) Utility model Registration 2580266 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 65/00-65/08 H01L 21/205 H01L 21/3065

Claims (8)

(57) [Claims] And 1. A processing object, the processing fluid, ionizing the process fluid, dissociation, and discharge apparatus for processing activated, release
A dielectric barrier discharge lamp in which an electric gas is sealed , and a processing method for processing an object having a processing chamber containing the dielectric gas, comprising: a dielectric barrier discharge lamp that discharges at least the object simultaneously with discharge processing of the processing fluid; A method using a dielectric barrier discharge lamp, characterized by irradiating with radiation emitted from a source. 2. The lamp according to claim 1, wherein the dielectric barrier discharge lamp has a wavelength range from 180 to 200 and from 165 to 19 in nm.
The method according to claim 1, wherein the lamp has radiation in at least one wavelength range of 0, 240 to 255, 200 to 240, 120 to 190, and 300 to 320. . 3. A processing method of the discharge device using a dielectric barrier discharge lamp as claimed in 2 claim 1 which is characterized in that a dielectric barrier discharge device. 4. A ashing method characterized in that using a process method using a dielectric barrier discharge lamp according to claims 1 to 3. 5. A surface modification method characterized in that using a process method using a dielectric barrier discharge lamp according to claims 1 to 3. 6. A film forming method characterized in that using a process method using a dielectric barrier discharge lamp according to claims 1 to 3. 7. The discharge device is a dielectric barrier discharge device, wherein at least a part of the dielectric of the dielectric barrier discharge device is an oxide or nitride of an element contained in a substance to be formed. 3. A film forming method using the processing method using a dielectric barrier discharge lamp according to claim 1 or 2 . 8. The etching method is characterized in that using a process method using a dielectric barrier discharge lamp according to claims 1 to 3.