JP2018098240A - Ultraviolet treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultraviolet treatment device that is able to reduce an amount of expelled ozone as much as possible even though the device is able to sufficiently obtain an action by ozone and is able to highly efficiently emit light to an object to be treated.SOLUTION: An ultraviolet treatment device according to the present invention comprises: a non-sealed type treatment chamber 11; an ultraviolet light source that emits ultraviolet to a work piece W disposed in the treatment chamber 11; a gas supply system 30 that supplies treatment gas into the treatment chamber 11; a gas exhaust system 40 that expels gas in the treatment chamber 11; and control means 55 that controls one or both of an amount that the treatment gas is supplied and an amount that gas is expelled from the treatment chamber, such that oxygen concentration in the treatment chamber 11 or an oxygen concentration value detected by oxygen concentration detection means 50 contained in gas circulated in the gas exhaust system fall in the range of 0.8 to 10 vol%.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an ultraviolet treatment apparatus that is preferably used when, for example, a treatment gas is activated by irradiating ultraviolet rays with a treatment gas to act on the treatment object.

  At present, dry cleaning methods are widely used in, for example, removal processing of a resist attached to a pattern surface of a template in a nanoimprint apparatus and cleaning processing of a glass substrate for a liquid crystal or a silicon wafer. As such a dry cleaning method, an optical cleaning method using ultraviolet rays is known. In particular, a photo-cleaning method using active species such as ozone and oxygen radicals generated by vacuum ultraviolet rays radiated from an excimer lamp or the like can be used preferably because a predetermined treatment can be performed more efficiently and in a short time. Has been.

FIG. 3 is a cross-sectional view schematically showing a configuration example of a conventional ultraviolet ray processing apparatus used for the optical cleaning process of the template surface used in the nanoimprint apparatus. This ultraviolet ray processing apparatus is disclosed in Patent Document 1, for example.
This ultraviolet ray processing apparatus includes a casing 60 having a substantially rectangular parallelepiped shape having an opening on an upper wall, and an ultraviolet transmitting window 61 made of, for example, quartz glass has a frame shape in the opening in the casing 60. The fixing plate 62 is fixed and provided.

  An ultraviolet lamp 65 made of, for example, an excimer lamp is disposed inside the housing 60 so as to face the ultraviolet transmission window 61. In addition, two rectangular cylindrical gas flow path members 66 through which the cooling gas flows are provided in the housing 60. More specifically, each gas flow path member 66 has a plurality of gas flow ports 67 formed on the upper wall so as to be spaced apart from each other and aligned in the longitudinal direction, It arrange | positions and is fixed in the state which contact | connects the side wall inner surface of the housing | casing 60. FIG. Each gas flow port 67 is continuous with a gas flow path 63 that opens around the ultraviolet light transmission window 61 on the upper surface of the housing 60.

This ultraviolet ray processing apparatus is used with the ultraviolet ray transmitting window 61 disposed so as to face the pattern surface of the template 75 held by the template holding mechanism 70 via a gap.
In the ultraviolet processing apparatus, the cooling gas discharged to the outside of the housing 60 through the gas flow passage 63 is supplied to the gas flow path member 66, so that the cooling gas is discharged into the ultraviolet transmission window 61 and the template 75. It is distributed in the gap between. In this state, when the ultraviolet lamp 65 is turned on, vacuum ultraviolet rays from the ultraviolet lamp 65 are applied to the pattern surface of the template 75 through the ultraviolet transmission window 61, and the template 75 is subjected to a light cleaning process.
Here, if the cooling gas contains oxygen, ozone is generated by irradiation with vacuum ultraviolet rays. Since there is a safety problem if the generated ozone is left as it is, the gas in the processing space where the light cleaning process is performed is usually exhausted by an exhaust device via an ozone removing means.

JP 2011-155160 A

Thus, for example, in a production line such as a liquid crystal substrate, in order to save space, it is rare that a processing chamber in which an object to be processed is subjected to light cleaning processing is sealed with a shutter or the like. For this reason, although the atmosphere in the processing chamber is usually replaced with an inert gas, the oxygen concentration is high and the concentration is not controlled, and the amount of ozone generated in the processing chamber tends to increase. .
In addition, it is necessary to maintain a negative pressure in the processing chamber in order to prevent ozone from diffusing to the surroundings. For this reason, air tends to flow from the surroundings into the processing chamber, the oxygen concentration in the processing chamber tends to increase, and the amount of ozone generated in the processing chamber increases.
As described above, the gas in the processing chamber is exhausted by the exhaust device through the ozone removing means. However, when the concentration of ozone contained in the gas exhausted from the processing chamber becomes high, a large ozone removal device or the like must be attached as an ozone removal means, which increases the size of the ultraviolet treatment device as a whole. become.
On the other hand, if the oxygen concentration in the processing chamber is too low in order to reduce the amount of ozone discharged, the effect of ozone generated in the processing of the object to be processed cannot be sufficiently obtained, so that the processing efficiency decreases. End up.

  The present invention has been made based on the circumstances as described above, and is capable of sufficiently obtaining the action of ozone and performing light irradiation treatment of an object to be processed with high efficiency. It aims at providing the ultraviolet-ray processing apparatus which can reduce the quantity of the discharged | emitted ozone as much as possible.

The ultraviolet treatment apparatus of the present invention includes a non-sealed treatment chamber,
An ultraviolet light source for irradiating ultraviolet rays to an object to be processed disposed in the processing chamber;
A gas supply system for supplying a processing gas into the processing chamber;
A gas exhaust system for exhausting the gas in the processing chamber;
Oxygen concentration detection means for detecting the oxygen concentration in the processing chamber or the oxygen concentration contained in the gas flowing through the gas exhaust system;
Either or both of the supply amount of the processing gas and the exhaust amount of the gas exhausted from the processing chamber so that the oxygen concentration value detected by the oxygen concentration detection means falls within the range of 0.8 to 10 vol%. And a control means for controlling.

In the ultraviolet treatment apparatus of the present invention, the gas exhaust system includes an ozone removal means comprising an ozone removal filter,
It is preferable that the oxygen concentration detection means is for detecting the oxygen concentration contained in the gas that has passed through the ozone removal means.

  In the ultraviolet processing apparatus of the present invention, it is preferable that the gas exhaust system includes an aspirator as an exhaust apparatus for exhausting the gas in the processing chamber.

According to the ultraviolet ray processing apparatus of the present invention, since the ultraviolet ray irradiation treatment is performed in a state where the oxygen concentration in the non-sealed processing chamber is controlled, the action of ozone generated by the ultraviolet ray irradiation can be sufficiently obtained. While the ultraviolet irradiation treatment can be performed with high efficiency, the amount of ozone discharged can be reduced as much as possible.
In addition, since the amount of ozone discharged is small, it is not necessary to use a large ozone removing device as an ozone removing means provided in the gas exhaust system, and the device itself can be enlarged because it can be handled by an ozone removing filter. You can avoid that.

  Further, since the gas exhaust system is configured to include an aspirator as an exhaust device for exhausting the gas in the processing chamber, the exhaust amount of the gas exhausted from the processing chamber can be finely adjusted. The oxygen concentration in the room can be accurately controlled, and the above effect can be obtained more reliably.

It is sectional drawing which shows roughly the example of 1 structure of the ultraviolet-ray processing apparatus of this invention. It is sectional drawing cut | disconnected by the plane along the conveyance direction of a to-be-processed object which shows the structure of the process chamber in the ultraviolet-ray processing apparatus shown in FIG. It is sectional drawing which shows roughly the example of 1 structure of the conventional ultraviolet-ray processing apparatus used for the optical cleaning process of the template surface used in a nanoimprint apparatus.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a cross-sectional view schematically showing one configuration example of the ultraviolet ray processing apparatus of the present invention. FIG. 2 is a sectional view schematically showing the configuration of the processing chamber in the ultraviolet processing apparatus shown in FIG. 1 and cut along a plane along the conveyance direction of the workpiece.
This ultraviolet ray processing apparatus is provided with a housing 10 in which, for example, a workpiece loading / unloading port 12 that opens to the side is formed. It is carried into or out of the casing 10 through the article loading / unloading port 12 (in FIG. 1, the direction of conveyance of the workpiece W is indicated by a white arrow). The casing 10 is provided with, for example, a flat shutter member 25 that opens and closes the workpiece loading / unloading port 12. The shutter member 25 does not completely seal the internal space of the housing 10 from the outside air (atmosphere outside the apparatus), and a gap is formed between the inner surface of the shutter member 25 and the outer surface of the housing 10 in the closed state. Thus, the non-sealed processing chamber 11 is formed inside the housing 10. In this example, the shutter member 25 is driven up and down by a drive mechanism (not shown) to open and close.

In this example, the internal space of the housing 10 is partitioned by a plate-like window member 18 provided in a horizontally extending state above the workpiece loading / unloading port 12, and the lower space portion is treated. The upper space is a light source arrangement chamber 15 in which an ultraviolet light source is arranged. As the ultraviolet light source, for example, a rod-shaped ultraviolet lamp 20 is used. The ultraviolet lamp 20 is arranged in such a posture that its central axis extends horizontally, and ultraviolet rays from the ultraviolet lamp 20 are irradiated toward the workpiece W through the window member 18. The window member 18 is made of a material that transmits ultraviolet rays from the ultraviolet lamp 20, for example, synthetic quartz glass.
In addition, in the ultraviolet-ray processing apparatus of this invention, the to-be-processed object W may be directly irradiated with the ultraviolet-ray from the ultraviolet lamp 20, for example. That is, the configuration may be such that the window member 18 is not provided, and in this case, the ultraviolet lamp 20 has a separation distance of, for example, 1 to 10 mm from the workpiece W disposed in the processing chamber 11. It is set as the structure arrange | positioned in the position.

  As the ultraviolet lamp 20, it is preferable to use a lamp that emits vacuum ultraviolet rays (ultraviolet rays having a wavelength of 200 nm or less). Specifically, for example, a low-pressure mercury lamp that emits vacuum ultraviolet rays of 185 nm, a xenon excimer lamp that emits vacuum ultraviolet rays having a center wavelength of 172 nm, or a xenon gas sealed in the arc tube, and the inner surface of the arc tube, for example, A fluorescent excimer lamp formed by applying a phosphor that emits vacuum ultraviolet rays of 190 nm can be exemplified.

  In the processing chamber 11, a gas supply system 30 that supplies a processing gas into the processing chamber 11 through a processing gas supply port 13 formed in the housing 10, and a gas exhaust system 40 that exhausts the gas in the processing chamber 11. And are connected.

  In the gas supply system 30, a processing gas supply pipe 31 is connected by piping to a processing gas supply port 13 formed at one end of the housing 10, and a processing gas supply source 32 is connected to the other end of the processing gas supply pipe 31. It is configured to be connected through 33.

  The processing gas is introduced to dilute the oxygen concentration in the processing chamber 11, and for example, an inert gas or a gas obtained by mixing oxygen with an inert gas is used. For example, nitrogen gas or argon gas can be used as the inert gas.

  As the flow rate control means 33, for example, a mass flow controller can be used.

  The gas exhaust system 40 is, for example, a rectangular cylindrical exhaust gas flow path member 41 provided in the vicinity of the workpiece loading / unloading port 12 in the processing chamber 11, and the exhaust gas flow path member 41. A gas exhaust pipe 42 connected to a gas exhaust port 14 formed in the housing 10 at a position on one end side in the lengthwise direction, and a gas exhaust apparatus connected to the gas exhaust pipe 42 via an ozone removing means 43 It is comprised by.

  The exhaust gas flow path member 41 is formed, for example, with a plurality of gas inlets 41a arranged on the bottom wall and spaced apart from each other in the length direction, for example, above the workpiece loading / unloading port 12. In the position. The gas in the processing chamber 11 that flows into the exhaust gas flow path member 41 through each gas inlet 41a of the exhaust gas flow path member 41 flows toward one end in the length direction and is a gas discharge port. 14 (shown by arrows filled in black in FIGS. 1 and 2). As described above, the exhaust gas flow path member 41 is provided in the vicinity of the workpiece loading / unloading port 12 so that the air taken in from the outside can be directly discharged into the exhaust gas flow path. Since it can be caused to flow into the member 41, it becomes easy to prevent particles from entering the processing chamber 11 from the outside.

  As the ozone removing means 43, for example, an ozone removing filter in which an ozone removing catalyst made of, for example, manganese dioxide is supported on a substrate made of a honeycomb structure formed of inorganic fiber paper can be used.

  As the gas exhaust device, for example, a device that creates a decompressed state and exhausts the gas in the processing chamber 11 is used. In this example, as the gas exhaust device, an aspirator 45, in particular, a device using a driving gas such as dry air or clean dry air (CDA) (ejector) is used. As the gas exhaust device, for example, a pump or the like can be used. However, since the exhaust amount of the gas discharged from the processing chamber 11 can be finely adjusted by controlling the supply amount of the driving gas, the aspirator 45 is used. Is preferred. In FIG. 2, 46 is a driving gas supply source for the aspirator 45, and 47 is a flow rate control means for controlling the amount of driving gas supplied to the aspirator 45.

  Thus, in the above-described ultraviolet processing apparatus, oxygen concentration detecting means 50 for detecting the oxygen concentration in the processing chamber 11 or the oxygen concentration contained in the gas flowing through the gas exhaust system 40 is provided, and the processing is performed. Control means 55 is provided for controlling the gas supply amount or the gas exhaust amount exhausted from the processing chamber 11 based on the oxygen concentration value detected by the oxygen concentration detection means 50.

The oxygen concentration detection means 50 is not particularly limited. For example, it is preferable to use a zirconia oxygen sensor because it has a high response speed and is not affected by, for example, CO ₂ gas.
In the case of detecting the oxygen concentration contained in the gas flowing through the gas exhaust system 40, the oxygen concentration detecting means 50 is for detecting the oxygen concentration contained in the gas that has passed through the ozone removing means 43. Is preferred. That is, it is preferable that the oxygen concentration detection means 50 is provided at a position on the downstream side (discharge side) of the ozone removal means 43 in the gas flow direction. With such a configuration, the gas introduced (sampled) into the oxygen concentration detection means 50 is in a state in which ozone is removed or the ozone concentration is reduced. Can be reduced.
When detecting the oxygen concentration in the processing chamber 11, it is preferable to sample the gas in the vicinity of the workpiece W in the processing chamber 11.

The control means 55 selects either the supply amount of the processing gas or the exhaust amount of the gas exhausted from the processing chamber 11 so that the oxygen concentration value detected by the oxygen concentration detection means 50 falls within the range of 0.8 to 10 vol%. It has a function of controlling either or both. Moreover, it is preferable that the oxygen concentration value in the process chamber 11 is set within a range of 1 to 10 vol%.
Specifically, the control means 55 determines the processing gas so that the detection signal according to the oxygen concentration output from the oxygen concentration detection means 50 corresponds to a specific oxygen concentration value set within the above range. It is desirable to have a function of performing feedback control on one or both of the supply amount and the gas exhaust amount.
The processing gas supply amount and the gas exhaust amount are set on the basis of the oxygen concentration value detected by the oxygen concentration detection means 50, and the operating conditions of the gas supply system 30 and the gas exhaust system 40 are input to the control means 55. For example, it may be controlled manually.

  When the oxygen concentration in the processing chamber 11 is lower than 0.8 vol%, the action of ozone generated by irradiating oxygen with vacuum ultraviolet rays from the ultraviolet lamp 20 is not sufficiently obtained, and the processing of the workpiece W is performed. Efficiency is reduced. On the other hand, when the oxygen concentration in the processing chamber 11 is higher than 10 vol%, the vacuum ultraviolet light from the ultraviolet lamp 20 is absorbed by oxygen, and the amount of vacuum ultraviolet light applied to the processing object W is reduced. W processing efficiency decreases.

Further, in the above-described ultraviolet processing apparatus, a state where the exhaust amount of the gas exhausted from the processing chamber 11 is slightly larger than the supply amount of the processing gas, that is, the inside of the processing chamber 11 is in a negative pressure state with respect to outside air. As described above, the operations of the gas supply system 30 and the gas exhaust system 40 are preferably controlled by the control means 55. Thereby, the oxygen concentration in the processing chamber 11 can be controlled to a lower concentration within the above-described concentration range, and high processing efficiency can be obtained as shown in the results of an experimental example described later.
As a specific example, for example, when the amount of processing gas supplied to the processing chamber 11 having a volume of 2 liters is 20 liters / min, the amount of gas exhausted from the processing chamber 11 is, for example, 22-30. Liter / min.

  The operation of the ultraviolet processing apparatus will be described. First, in a state where the workpiece W is carried into the processing chamber 11 and the shutter member 25 is closed, the supply of processing gas controlled by the flow rate control means 33 is performed. The gas is supplied into the processing chamber 11 in an amount and the aspirator 45 is driven, and the gas existing in the processing chamber 11 is exhausted from the processing chamber 11 through the exhaust gas passage member 41 with a controlled exhaust amount. Thereby, the atmosphere in the processing chamber 11 is replaced and maintained in a predetermined negative pressure state, for example.

  In this state, the oxygen concentration contained in the gas flowing through the gas exhaust system 40 is detected by the oxygen concentration detection means 50, for example. 2, the oxygen concentration in the processing chamber 11 may be detected by the oxygen concentration detection means 50. Then, either the supply amount of the processing gas or the exhaust amount of the gas exhausted from the processing chamber 11 is controlled by the control means 55 so that the oxygen concentration value detected by the oxygen concentration detection means 50 becomes a value within a predetermined concentration range. Either or both are feedback controlled.

In a state where the oxygen concentration in the processing chamber 11 is maintained at a predetermined level, the ultraviolet lamp 20 is turned on, so that the vacuum ultraviolet rays from the ultraviolet lamp 20 are directed toward the workpiece W through the window member 18. Irradiated. Thus, the treatment of the workpiece W by the action of the vacuum ultraviolet rays reaching the workpiece W and the action of the active species and ozone generated by irradiating the vacuum ultraviolet rays to the oxygen in the treatment chamber 11, for example, A cleaning process is performed.
On the other hand, the gas in the processing chamber 11 containing the generated ozone is exhausted from the processing chamber 11 through the exhaust gas flow path member 41. And after ozone contained in the said gas is removed by the ozone removal means 43, it is discharged | emitted outside the apparatus.

Thus, according to the above-described ultraviolet treatment apparatus, the ultraviolet irradiation treatment is performed in a state where the oxygen concentration in the non-sealed processing chamber 11 is controlled to a size within a specific range. The amount of ozone discharged can be reduced as much as possible while the effect of the ozone to be obtained can be sufficiently obtained and the ultraviolet irradiation treatment can be performed with high efficiency.
Further, since the amount of ozone discharged is small, it is not necessary to use a large ozone removing device as the ozone removing means 43 provided in the gas exhaust system 40, and it can be dealt with by an ozone removing filter. Can be avoided.

  Further, since the gas exhaust system 40 includes an aspirator 45 as an exhaust device for exhausting the gas in the processing chamber 11, fine adjustment of the exhaust amount of the gas exhausted from the processing chamber 11 is possible. Therefore, the oxygen concentration in the processing chamber 11 can be accurately controlled, and the above effect can be obtained more reliably.

[Example 1]
In accordance with the configuration shown in FIGS. 1 and 2, an ultraviolet processing apparatus having the following specifications was produced.
Dimensions of the processing chamber (11) (length × width × height): 210 mm × 280 mm × 32 mm, volume of the processing chamber (11): about 2 liters Material of the processing object (W): synthetic quartz glass, processing target ( W) dimensions (length x width): 152 mm x 152 mm
Ultraviolet lamp (20): xenon excimer lamp with an output of 50 W Distance between window member (18) and workpiece (W): 3 mm
Gas exhaust device: Aspirator using clean dry air as driving gas Ozone removal means (43): Ozone removal filter in which an ozone removal catalyst made of manganese dioxide is supported on a substrate made of a honeycomb structure formed of inorganic fiber paper , Dimensions: 50 × 50 × 75mm
Oxygen concentration detection means (50): Zirconia type oxygen sensor Processing gas: Nitrogen gas

In the above-described ultraviolet processing apparatus, oxygen in the processing chamber is appropriately controlled by appropriately controlling one or both of the processing gas supply amount to the processing chamber and the exhaust amount of the gas discharged from the processing chamber (the driving gas supply amount to the aspirator). In a state where the concentration was controlled to a concentration value according to the following Table 1, the xenon excimer lamp was turned on to perform ultraviolet irradiation treatment on the workpiece.
For example, when the processing gas supply amount to the processing chamber is controlled to 20 liters / min, the driving gas supply amount to the aspirator is set to 38 liters / min, and the exhaust amount of gas discharged from the processing chamber is controlled to 22 liters / min. In addition, the oxygen concentration in the processing chamber detected by the zirconia oxygen sensor could be controlled to 3 vol%.
In the ultraviolet irradiation treatment, the ultraviolet irradiation time was 120 sec.

Then, the contact angle theta ₁ with pure water of the surface of the workpiece after the ultraviolet irradiation treatment was measured, the difference between the contact angle theta ₀ with pure water on the surface of the object before the ultraviolet irradiation treatment ([Delta] [theta] = Using θ ₁ −θ ₀ ) as the processing performance, the relationship between the oxygen concentration in the processing chamber and the processing performance was examined. As a result, when the oxygen concentration was controlled within the range of 0.8 to 10 vol%, Δθ was 10 ° or more, and it was confirmed that high cleaning performance was obtained.
Further, when the concentration of ozone contained in the gas discharged from the processing chamber during the ultraviolet irradiation treatment was measured, the ozone concentration was 0. 0 in a state where the oxygen concentration was controlled within the range of 0.8 to 10 vol%. It was within the range of 2 to 3.3 ppm.

  As is clear from the above results, when the ultraviolet irradiation treatment is performed in a state where the oxygen concentration in the non-sealed processing chamber is controlled to a size within the range of 0.8 to 10 vol%, the ultraviolet irradiation treatment is performed. It has been confirmed that the amount of ozone discharged can be reduced as much as possible.

DESCRIPTION OF SYMBOLS 10 Housing | casing 11 Processing chamber 12 Workpiece carrying in / out opening 13 Processing gas supply port 14 Gas discharge port 15 Light source arrangement chamber 18 Window member 20 Ultraviolet lamp 25 Shutter member 30 Gas supply system 31 Processing gas supply pipe 32 Processing gas supply source 33 Flow control means 40 Gas exhaust system 41 Exhaust gas flow path member 41a Gas inlet 42 Gas exhaust pipe 43 Ozone removal means 45 Aspirator 46 Drive gas supply source 47 Flow rate control means 50 Oxygen concentration detection means 55 Control means 60 Housing 61 Ultraviolet light transmission window 62 Fixed plate 63 Gas flow path 65 Ultraviolet lamp 66 Gas flow path member 67 Gas flow port 70 Template holding mechanism 75 Template W Workpiece

Claims (3)

An unsealed processing chamber;
An ultraviolet light source for irradiating ultraviolet rays to an object to be processed disposed in the processing chamber;
A gas supply system for supplying a processing gas into the processing chamber;
A gas exhaust system for exhausting the gas in the processing chamber;
Oxygen concentration detection means for detecting the oxygen concentration in the processing chamber or the oxygen concentration contained in the gas flowing through the gas exhaust system;
Either or both of the supply amount of the processing gas and the exhaust amount of the gas exhausted from the processing chamber so that the oxygen concentration value detected by the oxygen concentration detection means falls within the range of 0.8 to 10 vol%. And a control means for controlling the ultraviolet ray processing apparatus. The gas exhaust system includes an ozone removing means including an ozone removing filter,
2. The ultraviolet processing apparatus according to claim 1, wherein the oxygen concentration detection means detects an oxygen concentration contained in a gas that has passed through the ozone removal means. The ultraviolet processing apparatus according to claim 1, wherein the gas exhaust system includes an aspirator as an exhaust apparatus that exhausts the gas in the processing chamber.

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