JPS60212226A - Ultraviolet ray treatment method - Google Patents

Abstract

PURPOSE:To enable uniform and rapid washing, by partitioning an ultraviolet ray source and an object to be treated in an ultraviolet ray permeable state and supplying gas forming nascent oxygen by ultraviolet rays only to the vicinity of the object to be treated. CONSTITUTION:Ozone or N2O is decomposed by ultraviolet rays of an ultraviolet ray source 2 to form nascent oxygen and the org. contaminant adhered to the surface of an object 5 to be treated is decomposed by said nascent oxygen to perform washing treatment. In this ultraviolet ray treatment method, the ultraviolet ray source 2 and the object 5 to be treated are partitioned by quartz glass 7 or an air curtain in an ultraviolet ray permeable state and gas forming nascent oxygen by ultraviolet rays (e.g., oxygen) is supplied only to the vicinity of the object 5 to be treated while a space including ultraviolet ray source 2 is brought to a vacuum atmosphere or a gaseous atmosphere such as nitrogen absorbing no ultraviolet rays. As a result, uniform and rapid washing is enabled in such a state that the supply amount of treating gas is reduced and the attenuation of ultraviolet rays is low.

Description

DETAILED DESCRIPTION OF THE INVENTION The invention is directed to ultraviolet treatment methods, such as UV10. It's about cleaning.

Ultraviolet light emitted from an ultraviolet source such as an ultraviolet lamp is used to decompose and clean organic contaminants, but when this ultraviolet source, for example a low-pressure mercury lamp, is turned on, it mainly emits light with a wavelength of 254 nm. Ultraviolet rays of the mercury resonance line are externally emitted, and accordingly, ultraviolet rays with a wavelength of 185 nm and a small amount of other wavelengths are also emitted.

Then, ozone is generated by ultraviolet rays with a wavelength of 185 nm, and then this ozone is decomposed by a wavelength of 254 nm to generate oxygen as a generating group, and organic pollutants are decomposed by the oxygen in the generating group and scattered in a gaseous state. It has been known. In addition, N20 is decomposed at a wavelength of 185 nm to generate the generating group # element, which causes organic pollution like ozone.
t- Decompose and scatter in gaseous state.

By the way, in the conventional method, the object to be treated is placed below an irradiation chamber in which an ultraviolet lamp is installed on the upper tooth, and while a gas containing commonly used gas such as oxygen is supplied into the irradiation chamber, ultraviolet rays are applied to the object. IIJt- was irradiated.

And if the distance between the ultraviolet ray rung and the object to be treated is small,
The heat of the lamp is projected onto the object to be treated, which has an adverse effect, and furthermore, the distribution of light irradiation on the surface of the object to be treated becomes uneven, leading to problems such as localized deviations in the decomposition of organic contaminants. Therefore, the distance between the ultraviolet lamp and the object to be treated must be increased to some extent. Therefore, the volume of the irradiation chamber increases, but for this reason, the ultraviolet rays generated by the lamp are absorbed by oxygen and generated ozone and attenuated before reaching the object to be treated, which slows down the processing speed of cleaning etc. It became. In addition, in order to maintain a high processing speed, it is necessary to supply a large amount of processing gas such as oxygen into the large volume irradiation chamber, and a small portion of this large amount of processing gas supplied is organic. Most of the processing gas was wastefully exhausted outside the irradiation chamber, only contributing to the decomposition of pollutants, and its efficiency was extremely low.

SUMMARY OF THE INVENTION The present invention has been made in view of these circumstances, and it is an object of the present invention to provide an ultraviolet treatment method that requires a small supply of a treatment gas such as oxygen, has low attenuation of ultraviolet rays, and has, for example, a high cleaning speed. shall be. The composition is ozone or N20'd by the light of the ultraviolet source.
+'lfF'? This is an ultraviolet treatment method in which organic contaminants adhering to the surface of the object to be treated are decomposed and cleaned using oxygen generated from the generated radicals. The space between the object and the object to be treated is divided in such a way that ultraviolet rays can pass through, and a gas that generates oxygen, which is a generating group due to ultraviolet rays, is supplied only to the vicinity of the object. It is characterized by a gas atmosphere that does not absorb.

The present invention will be specifically described below based on embodiments shown in the drawings.

Figure 1 shows a cross-sectional view of the equipment used in the embodiment of the present invention.The irradiation chamber 1 is built into the equipment box along the path shown in the diagram and has no double structure, so that the ozone generated does not leak outside. It has become. In the upper part of the irradiation chamber 1, there is a U as an ultraviolet lamp 2.
Two letter-shaped 350W high-output low-pressure mercury lamps are arranged, a mirror 3 is arranged behind them, and the light from the ultraviolet lamp 2 is directed downward. A cooling water channel 4 is fixed to the upper surface of the ceiling of the irradiation chamber 1 and is water-cooled. Processed object 5
is a wafer with a diameter of about 10 ctn, and is supported by a support 6 fixed to the bottom surface, and the distance from the ultraviolet lamp 2 to the object to be processed 5 is 10ω. It is preferable to provide a temperature control device under the object to be treated 5 to adjust the temperature to an appropriate temperature and promote the decomposition of organic contaminants.

Next, a quartz glass plate 7 is disposed at a position 2an above the object to be processed 5, and partitions the object to be processed 5 and the ultraviolet lamp 2, but the space containing the object to be processed 5t is Much smaller than the space containing rung 2. Below the quartz glass plate 7, there are provided an inlet hole 11 for supplying a gas containing a processing gas such as oxygen, and an exhaust hole 12 for discharging the internal gas together with decomposed contaminants. 12 The gas sucked in is treated in an ozone decomposition chamber and then released into the atmosphere. In the space above the quartz glass plate 7 and containing the ultraviolet lamp 2, there is a pressure reduction hole 15 connected to a pressure reduction device, and an inert gas such as nitrogen gas that does not absorb ultraviolet rays is injected. A hole 14 is provided. However, the injection hole 214 may not be provided, and the space containing the ultraviolet lamp 2 may be evacuated so that ultraviolet rays are absorbed in this space and eliminated.

FIG. 2 shows an embodiment in which an air curtain is provided in place of the quartz glass plate 7, and a nozzle 81 for discharging nitrogen gas and a nozzle 81 for sucking the nitrogen gas are located at positions corresponding to the quartz glass plate 7 in FIG. A suction hole 82 for receiving the air is provided oppositely.

Therefore, an air curtain of nitrogen gas is placed slightly above the object to be processed 5, and the ultraviolet rays are transmitted through this, but the processing gas is not diffused upward beyond this.

As described above, although the embodiment using the quartz glass plate and the air curtain is shown in FIG. 1 and FIG. 2, the embodiment is not limited to these.
and partitioned in a state where ultraviolet rays can pass through,
It is sufficient if the processing gas does not diffuse beyond this range.

Thus, the processing gas is supplied near the object to be processed 5,
The space containing the ultraviolet lamp 2 is reduced in pressure, or nitrogen gas is further injected. Then, when the ultraviolet lamp 2 is turned on, the surface of the object to be treated 50 is irradiated with ultraviolet rays, and organic contaminants adhering to the surface are decomposed and processing such as cleaning is performed.

Here, since there is a sufficient distance between the ultraviolet lamp 2 and the object to be processed 5, the amount of heat from the ultraviolet lamp 2 projected onto the surface of the object to be processed 5 is small, and this adverse effect is eliminated. Ru. Furthermore, the light from the ultraviolet lamp 2 is uniformly irradiated, so that there are no spots that are poorly cleaned. And ultraviolet lamp 2
Since there is no oxygen gas in the large space containing the space, the ultraviolet rays do not attenuate in this space, and the object to be processed 5 can be irradiated with strong ultraviolet rays, so the processing speed is significantly increased and the processing time is shortened. In this way, energy saving can be achieved. Furthermore, since the volume of the space into which the processing gas is supplied is small, the required supply amount is much smaller, and the amount of processing gas can be greatly reduced.

Next, to explain this effect using specific numbers, in a conventional example that is not partitioned by a quartz glass plate 7 or the like, the distance between the lamp and the object to be processed is 10 crn, the volume of the irradiation chamber is 15 t, and the depth is 20 crn.

In a model in which ozone with a concentration of 500 ppm is uniformly distributed inside this, the ultraviolet absorption coefficient of ozone at a wavelength of 254 nm is α = 300 atm-'・40 vL+ -', so the 254-nm ultraviolet rays will not reach the object to be treated. Approximately 80 chi will be absorbed. In contrast, the present invention
If the above model 1 is sectioned at a position 2 crn above the object to be treated, about 25 rays of ultraviolet light will be absorbed, which is a much greater effect than in the conventional example.

On the other hand, the processing speed is proportional to the flow rate of oxygen gas, but in both the conventional example and the present invention, in order to process oxygen gas gold at a flow rate of 33"/min, the conventional example requires a supply amount of i Q A11n. On the other hand, in the present invention, it was about 1.5'/rn
In, the oxygen supply amount can be saved by nearly 90%.

As understood from the embodiments described above, the present invention
The space between the ultraviolet ray source and the object to be treated is divided in such a way that the ultraviolet rays can pass through, and the gas that generates all the oxygen in the generation group by the ultraviolet rays is supplied only in the vicinity of the object to be treated, and the space containing the ultraviolet ray source is kept in a vacuum or in a vacuum. Since the gas atmosphere does not absorb ultraviolet rays, according to the present invention, it is possible to provide an ultraviolet ray treatment method that requires only a small amount of treatment scum, reduces the attenuation of ultraviolet rays, enables uniform cleaning, and has a high processing speed. . In addition to cleaning, this method can also be applied to photoresist ashing and the like.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, and Figure 2 of the body is a sectional view of another embodiment. 1...Irradiation chamber 2...Ultraviolet light beam 6...Mirror 5...Object to be treated 6...Support 7...Quartz glass plate appearance person Ushio Inc. agent Patent attorney Toranosuke Tahara

Claims (1)

[Claims] Ozone or N, 0 is decomposed by the light of the ultraviolet source, and the generated radical oxygen adheres to the surface of the W-treated body.41! This is an ultraviolet treatment method that decomposes contaminants and treats their bulk, etc., and uses quartz glass, air curtains, etc. to partition the ultraviolet source and the object to be treated so that the ultraviolet rays can pass through. In addition to supplying gas that generates oxidation by ultraviolet rays only near the body,
An ultraviolet treatment method characterized in that the space containing the ultraviolet source is a vacuum or a gas atmosphere that does not absorb ultraviolet rays.