JPH06231735A - Ashing device formed by using dielectric barrier discharge lamp - Google Patents

Abstract

PURPOSE:To ash a large area photoresist uniformly at high speed, and also downsize a device by using dielectric barrier discharge lamps as an ultraviolet ray radiating source. CONSTITUTION:In dielectric barrier discharge lamps 4a-4e, xenon gas is used as generating gas, and ultraviolet rays are emitted. Thereby, a part of treating fluid oxygen 1 ejected from a supply port 2 is converted into ozone by the ultraviolet rays in preliminary space 6 in an ashing duct 3. Mixed gas of the ozone and the oxygen is blown upon a photoresist. An active oxygen atom generated by decomposition of an oxygen molecule in treating space 7 acts directly on the photoresist before the ozone is generated. Thereby, the photoresist changed in quality after an ion is implanted can be removed at high speed, and the active oxygen atom by decomposition of the ozone generated in the preliminary space 6 acts also on the photoresist, so that the photoresist can be ashed and removed at high speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called ashing device for removing a photoresist applied on a silicon wafer or the like by irradiating the photoresist with ozone so that the photoresist is ashed and removed. .

[0002]

2. Description of the Related Art As a technique related to the present invention, for example, Japanese Patent Laid-Open Publication No. 1-144560 discloses a dielectric barrier discharge (also called ozonizer discharge or silent discharge. Revised new edition "Discharge Handbook" issued by the Institute of Electrical Engineers of Japan. Heisei 1
It describes a lamp using the 7th edition of the 6th edition of June 2010 (see page 263). Further, it has been known for a long time that organic substances can be removed by irradiating ultraviolet rays in an ozone atmosphere, and an ashing device using a low pressure mercury discharge lamp as an ultraviolet light source is used. These conventional apparatuses have problems that it is difficult to ash a large area uniformly, and the ashing speed is not always sufficient.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an ashing device capable of ashing a large-area object uniformly and at high speed.

[0004]

DISCLOSURE OF THE INVENTION The above object of the present invention is to provide a dielectric barrier discharge as a radiation source of ultraviolet rays in an apparatus for incineration of an object to be treated by contacting it with ozone under irradiation of ultraviolet rays. Achieved by using a lamp. Further, the dielectric barrier discharge lamp has a wavelength range of 180 to 200, 165 to 19 in nm range.
0, and by selecting the emission gas of the dielectric barrier discharge lamp to have radiation in at least one wavelength range of 120 to 190, or the dielectric barrier discharge lamp has a wavelength range expressed in nm. 240 to 2
The above objects can be achieved even further by choosing the emission gas of the dielectric barrier discharge lamp so as to have radiation in the wavelength range of at least one of 55, 200 to 240 and 300 to 320.

[0005]

When the dielectric barrier discharge lamp is used as a radiation source of the ultraviolet rays in an apparatus for incineration of the objects to be treated by contacting ozone with the ultraviolet rays under irradiation, the dielectric barrier is used. A discharge lamp emits light in a wavelength range not possible with conventional low-pressure mercury discharge lamps, and with high efficiency as a monochromatic light in a narrow wavelength range. It changes the spectral distribution by changing the input power to the lamp. Since it has the features that it can change the light output without changing the temperature of the lamp and that the temperature of the lamp can be lowered, it is highly efficient to generate light with a characteristic spectral distribution that cannot be obtained by combining conventional glow or arc discharge lamps. Therefore, it is possible to uniformly incinerate a large-area object with high efficiency and high speed using a small device.

Further, the dielectric barrier discharge lamp has a nm
Wavelength range in units 180 to 200, 165 to 1
By selecting the luminescent gas of the dielectric barrier discharge lamp to have radiant light in at least one wavelength range of 90 and 120 to 190, these ultraviolet rays can generate ozone from oxygen, It is possible to incinerate without providing an ozone generator, and therefore it is possible to incinerate at high speed with a small device. Further, by radiating ultraviolet rays in the above wavelength range, high efficiency and high quality ashing can be achieved. Because, the ultraviolet light in the above wavelength range, at least, by using argon and fluorine, argon and chlorine, and xenon gas, respectively as the main light emitting gas, it is possible to emit light by the excimer molecules of each mixed gas, By using these gases, it is possible to realize a state in which the light emitting gas is less deteriorated and the light extraction window member is less deteriorated.

Further, the dielectric barrier discharge lamp comprises
By selecting the emission gas of the dielectric barrier discharge lamp to have radiation in at least one of the wavelength ranges 240 to 255, 200 to 240, and 300 to 320, expressed in m units, these ultraviolet rays are Since the energy of photons is small, ashing is possible without damaging a substrate such as a silicon wafer. Furthermore, by emitting ultraviolet rays in the above wavelength range, high efficiency,
High quality ashing is achieved. Because, the ultraviolet rays in the above wavelength range, at least, by using a mixed gas of krypton and fluorine, and krypton and chlorine as the main light emitting gas, respectively, it is possible to emit light by the excimer molecules of each mixed gas, By using these gases, it is possible to realize a state in which the light emitting gas is less deteriorated and the light extraction window member is less deteriorated.

[0008]

EXAMPLE FIG. 1 shows a schematic view of a method of ashing a photoresist which is an example of the present invention. Silicon wafer 8 in which dielectric barrier discharge lamps 4a, 4b, 4c, 4d, 4e are applied in the ashing duct 3 with a photoresist which is an object to be processed
Is provided close to. The silicon wafer 8 is supported by a support 5, which is a conventional means for changing the temperature of the object to be processed, such as an electric heater, the object to be processed and the dielectric barrier discharge lamp. 4a, 4
It has a moving mechanism for adjusting the distance between b, 4c, 4d, and 4e.

A schematic view of the coaxial cylindrical dielectric barrier discharge lamp used in the embodiment is shown in FIG. The discharge vessel 13 is made of quartz glass and has an inner tube 14 and an outer tube 15 arranged coaxially to form a hollow cylinder. The outer tube 15 also serves as a dielectric barrier for a dielectric barrier discharge and a light extraction window member, and an electrode 17 made of a metal net that transmits light is provided on the outer surface thereof. A cylindrical metal electrode 16 also serving as a reflection plate for ultraviolet rays is provided on the inner diameter portion of the inner tube 14. A cooling fluid 19 is flown inside the cylindrical metal electrode 16 to lower the temperature of the entire dielectric barrier discharge lamp.
A ring-shaped getter 18 is provided at one end of the discharge space 20. A discharge gas that forms excimer molecules by a dielectric barrier discharge is enclosed in the discharge space 20, and the transparent electrode 17 made of a metal mesh provided on the surface of the dielectric 15 and the reflection of ultraviolet rays on the inner diameter of the inner tube 14 are reflected. When a voltage is applied to the cylindrical metal electrode 16 also serving as a plate by the AC power supply 21, a so-called dielectric barrier discharge, which is also called an ozonizer discharge or a silent discharge, is generated in the discharge space 20, and the dielectric 1
5. Through the transparent electrode 17, ultraviolet rays are radiated with high efficiency. Although not shown in the figure, if necessary, the transparent electrode 1
The surface of 7 is covered with an ultraviolet-transparent resin, glass or the like to be electrically insulated. Further, it is desirable that the outer electrode 17 that is in direct contact with the object to be processed or the processing fluid is used at the ground potential.

In the first embodiment, xenon gas is enclosed as the main component of the light emitting gas of the dielectric barrier discharge lamps 4a, 4b, 4c, 4d and 4e, and the density is 172 nm.
It emits ultraviolet light in the wavelength range of 120 to 190 nm, which has a maximum value in the vicinity. The ultraviolet rays decompose oxygen molecules into active oxygen atoms with high efficiency, and the active oxygen atoms combine with oxygen molecules to generate ozone. A part of the processing fluid oxygen 1 injected from the processing fluid supply port 2, typically about 1%, is radiated from the dielectric barrier discharge lamp in the spare space 6 in the ashing duct 3. It is converted to ozone by ultraviolet rays of wavelength. A mixed gas of ozone and oxygen is sprayed onto the photoresist. Active oxygen atoms generated by decomposition of oxygen molecules in the processing space 7 directly act on the photoresist before generating ozone. The oxygen atom generated by the decomposition of this oxygen molecule has higher activity than the oxygen atom generated by the decomposition of ozone, so that it is possible to remove the deteriorated photoresist after the ion implantation, and it can be removed at high speed. I can. further,
Since active oxygen atoms generated by the decomposition of ozone generated in the spare space 6 also act on the photoresist, there is a high density of active oxygen molecules in the vicinity of the photoresist. It can be converted and removed.

Since the cooling fluid 19 is flown inside the cylindrical metal electrode 16 to lower the temperature of the entire dielectric barrier discharge lamp, there is no need to worry about heating of the photoresist by the dielectric barrier discharge lamp. The distance between the photoresist and the dielectric barrier discharge lamp can be made sufficiently small, and therefore, ultraviolet rays can be irradiated with high efficiency, and the photoresist can be ashed and removed at high speed. Moreover, unlike the conventional low-pressure mercury discharge lamp, the dielectric barrier discharge lamp does not change the light output characteristics such as radiation efficiency even if the length and the distance between the lamps are changed, so that a large area can be made uniform. It is possible to dispose the lamp so that it can irradiate the entire surface of the photoresist. Therefore, it is possible to uniformly ash a large area of photoresist with high efficiency. Also, unlike the conventional low-pressure mercury discharge lamp, by changing the input power to the lamp, the light output can be changed without changing the spectral distribution, so the input power to the lamp and the dielectric barrier discharge lamp and photo By adjusting the distance between the resists, the amount of ultraviolet rays applied to the photoresist can be controlled. When the amount of ultraviolet rays applied is small, ashing can be performed without damaging the silicon wafer 8 due to the ultraviolet rays. Increasing the amount of ultraviolet rays applied to the photoresist enables high-speed ashing of the deteriorated photoresist that is difficult to ash.

The features of the embodiment of the present invention described above can be summarized as follows in comparison with a conventional low pressure mercury discharge lamp and an ashing apparatus using ozone. (1) It is not necessary to provide an ozone generator for supplying ozone, and a small and simple ashing device can be obtained. (2) Since more active oxygen atoms are obtained, it is possible to ash the altered photoresist that is difficult to ash at high speed. (3) Since the photoresist is hardly heated by the dielectric barrier discharge lamp, it is possible to incinerate at a low temperature. (4) A large area photoresist can be uniformly ashed with high efficiency. (5) It is possible to control the amount of ultraviolet rays applied to the photoresist, and thus high-quality ashing is possible.

In the above example, 120 to 190 nm
A dielectric barrier discharge lamp that emits ultraviolet light in the range of 160 to 190 nm and 180 to 2 was used.
A similar effect can be obtained using a dielectric barrier discharge lamp that emits UV radiation in the 00 nm range.

In the second embodiment, when ozone is supplied as the processing fluid 1, the dielectric barrier discharge lamps 4a, 4b, 4c, 4d and 4e have relatively long wavelengths of 240 to 255 nm. 200 to 240 nm, 30
The luminescent material is selected to emit ultraviolet light in the range 0 to 320 nm. The ultraviolet rays decompose the ozone to generate active oxygen atoms, and ash the photoresist. Since the ultraviolet rays have a relatively long wavelength, the photon energy with which the photoresist is irradiated is small, and there is an advantage that the silicon wafer as the substrate is less damaged.

[0015]

As described above, according to the present invention,
It is possible to provide an ashing device capable of uniformly ashing a large area photoresist at a high speed with a small device.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of an example of a dielectric barrier discharge lamp used in the present invention.

[Explanation of symbols]

2 Processing Fluid Supply Ports 4a, 4b, 4c, 4d, 4e Dielectric Barrier Discharge Lamp 5 Support 8 Silicon Wafer 14 Inner Tube 15 Outer Tube 16, 17 Electrode 19 Cooling Fluid 20 Discharge Space 21 AC Power Supply

Claims (3)

[Claims] 1. A dielectric material, characterized in that a dielectric barrier discharge lamp is used as a radiation source of the ultraviolet ray in an apparatus for incineration of the object to be treated by contacting ozone with the ultraviolet ray under irradiation. Ashing device using a barrier discharge lamp. 2. The dielectric barrier discharge lamp has a wavelength range of 180 to 200, 165 to 19 expressed in nm.
An ashing device using a dielectric barrier discharge lamp according to claim 1, wherein the ashing device has radiant light in the wavelength range of 0 and at least one of 120 to 190. 3. The dielectric barrier discharge lamp has wavelength ranges 240 to 255 and 200 to 24 expressed in nm.
The ashing device using the dielectric barrier discharge lamp according to claim 1, wherein the ashing device has radiated light in the wavelength range of 0 and at least one of 300 to 320.