JP2012128962A - Excimer lamp, and excimer light irradiating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an arc tube from being damaged in its early stages by accumulation of distortion caused by ultraviolet rays and distortion caused by regulating warpage, when mounting an excimer lamp including a long arc tube with the inside filled with noble gas, an electrode on its external surface, and an ultraviolet reflecting film formed on the inner wall surface of the arc tube excluding a light emitting part in an excimer irradiating device including a movement regulating body for regulating warpage of the excimer lamp caused by deformation by ultraviolet rays.SOLUTION: The center part of an arc tube 31 of an excimer lamp in the axial direction is bent so as to protrude in the direction of the light emitting part of the arc tube. In the excimer light irradiating device carrying the excimer lamp, the movement regulating part abutting with the center part of the excimer lamp from the ultraviolet reflecting film forming part side is provided in its casing, and a correction maintaining member abutting with the center part from the light emitting part side is also provided. The excimer lamp is linearly corrected and held by the correction maintaining member in the tube axis direction.

Description

  The present invention relates to an excimer lamp and an excimer light irradiation apparatus equipped with the excimer lamp, and more particularly to an excimer lamp and an excimer light irradiation apparatus in which an ultraviolet reflecting film is formed on the inner wall surface of an arc tube.

In a manufacturing process of a semiconductor or a liquid crystal substrate, a dry cleaning method using ultraviolet rays is widely used as a method for removing dirt such as an organic compound adhering to the surface of a silicon wafer or a glass substrate.
In particular, an excimer lamp mounted on an excimer light irradiation device for carrying out a cleaning method using active oxygen such as ozone using vacuum ultraviolet rays having a wavelength of 200 nm or less radiated from an excimer lamp is provided with an ultraviolet reflecting film. It is proposed in Japanese Patent Application Laid-Open No. 2010-80351 (Patent Document 1).
In Patent Document 1, in order to efficiently emit ultraviolet rays, the inner surface of the arc tube excluding the surface on the light emission direction side of the arc tube arranged linearly with respect to the object to be processed is composed of silica particles and alumina particles. An ultraviolet reflecting film is formed.

By the way, the arc tube in which the ultraviolet reflecting film is formed in this way, as the lighting time elapses, ultraviolet distortion is accumulated on the wall in the light emitting direction through which the ultraviolet rays are transmitted and contracts in the longitudinal direction. On the other hand, the wall on the side where the UV reflecting film is formed is not deformed because it is not affected by the UV distortion, and therefore the central portion of the arc tube warps to the UV reflecting film forming wall side, and the entire UV reflecting film is formed. There was a problem of warping in a convex shape toward the wall side.
When the excimer lamp is warped upward, the distance between the excimer lamp and the work surface such as the glass substrate, which is the object to be irradiated, is different between the excimer lamp and the central portion. However, there is a problem that uniform ultraviolet treatment cannot be performed.

In the above-mentioned Patent Document 1, in order to solve this problem, as shown in FIG. 7, a movement restricting body that restricts the central portion of the excimer lamp from warping due to the accumulation of ultraviolet distortion in the casing of the excimer light irradiation device. And the lower end of the movement restricting body is brought into contact with the central portion of the excimer lamp to satisfactorily solve the problem of warpage.
That is, in FIG. 7, the excimer lamp light irradiation device 1 has an excimer lamp 3 supported by a housing 2, and external electrodes 32 are provided on the upper and lower planes of the arc tube 31. Below the excimer lamp 3, the workpiece W is transported by the transport roller 6.
The movement restricting body 5 is provided substantially above the central portion of the excimer lamp 3, and the rotary roller 51 at the tip thereof is in contact with the excimer lamp 3 from above the arc tube 31. The movement restricting body 5 forcibly suppresses the deformation distortion caused by the accumulation and the central portion of the excimer lamp 3 from protruding upward.
Yes.

  However, in the above prior art, since the excimer lamp warping which is to be bent by using for a certain period of time is forcibly restricted, the total stress of the warpage regulating stress accumulated in the glass of the arc tube and the ultraviolet stress is a constant value. A new problem occurred that would lead to breakage.

JP 2010-80351 A

  The present invention has been made in view of the above-described problems of the prior art, and is arranged on a long arc tube having a sealed space in which a rare gas is sealed, and an outer surface of the arc tube. An excimer lamp comprising a pair of counter electrodes facing each other with the arc tube interposed therebetween and an ultraviolet reflecting film formed on an inner wall surface excluding the light emitting portion of the arc tube, the excimer due to deformation distortion due to ultraviolet rays. Providing a structure that prevents the arc tube from being damaged at an early stage due to the accumulation of ultraviolet ray distortion and warpage restriction strain when mounted on an excimer light irradiation device equipped with a movement restrictor that restricts lamp warping It is.

In order to solve the above problems, an excimer lamp according to the present invention is characterized in that a central portion in the tube axis direction of the arc tube is curved so as to protrude in a direction of a light emitting portion of the arc tube. To do.
In the excimer light irradiation apparatus equipped with the excimer lamp, the casing is provided with a movement restricting body that comes into contact with the ultraviolet reflective film forming part side at the center of the excimer lamp, and the correction that comes into contact with the light emitting part side. A maintenance member is provided, and the excimer lamp is straightened and held in the tube axis direction by the straightening maintenance member.

  According to the present invention, when an excimer lamp that is curved so that the central portion protrudes toward the light emitting portion side is mounted on the excimer light irradiation device, the tube axis is fixed by the correction maintaining member that contacts the lamp from the light emitting portion side. In the initial lighting, the mechanical strain due to this correction acts in a direction that is alleviated by ultraviolet rays, and the warp regulating stress is eliminated after the mechanical strain disappears after a predetermined time. Therefore, the elapsed time until the arc tube is damaged due to the accumulation of the combined stress of the warpage restricting stress and the ultraviolet stress is greatly extended, and the failure life of the lamp is reduced. Greatly improved.

Explanatory drawing of the excimer lamp which concerns on this invention. The side view of the axial direction of FIG. 1 is an overall view of an excimer light irradiation apparatus of the present invention. The principal part enlarged view of FIG. AA sectional drawing of FIG. The graph showing the effect of this invention. Conventional excimer lamp light irradiation device.

FIG. 1 shows an excimer lamp 3 according to the present invention. FIG. 1 (A) is a perspective view from the lower surface side, and FIG. 1 (B) is a transverse sectional view thereof. The arc tube 31 of the excimer lamp 3 has a rectangular shape in cross section and is elongated in the longitudinal direction, and external electrodes 32 and 32 are provided on the upper and lower surfaces thereof.
As shown in FIG. 1B, the inner surface of the arc tube 31 is coated with an ultraviolet reflecting film 33 on the upper surface side and the side surface to form an ultraviolet reflecting film forming portion 35, and an ultraviolet reflecting film is formed on the lower surface side. Is not formed, and the portion forms the light emitting portion 34.
As shown in FIG. 2, the arc tube 31 is curved so that the central portion thereof projects slightly by an amount L toward the light emitting portion 34 in the longitudinal axis direction.
The shape of the arc tube 31 is not limited to a flat shape having a square cross section, and may be a round shape or a so-called double tube structure.
Moreover, although the ultraviolet reflective film 33 showed what was formed in 3 surfaces of the arc_tube | light_emitting_tube 31, it is not restricted to this, You may form only in the upper surface.

An example of a method for manufacturing the arc tube 31 will be described as follows.
First, an arc tube having a predetermined cross-sectional shape is manufactured. At this time, the arc tube is not bent in the longitudinal direction.
Next, an ultraviolet reflecting film is formed on the inner surface of the arc tube excluding the light emitting portion.
Thereafter, the arc tube is sealed.
Next, both ends in the longitudinal direction of the arc tube are supported so that the light emitting part side is downward, and the center portion is pressed down by an amount corresponding to the amount L to be bent, and the entire arc tube is heated in this state. At this time, the heating temperature is raised until the arc tube is deformed and fixed in a curved state by a predetermined amount. Thereby, the light emission part which protruded below is formed.
Thereafter, electrodes are formed on the upper and lower surfaces of the curved arc tube.
Next, a predetermined discharge gas such as xenon is sealed in the arc tube to complete the lamp.

An excimer light irradiation apparatus 1 equipped with the curved excimer lamp 3 is shown in FIG.
3 is an overall view thereof, FIG. 4 is an enlarged view of a main part of FIG. 3, and FIG. 5 is a cross-sectional view taken along line AA of FIG.
As shown in FIG. 3, both ends of the excimer lamp 3 that is curved so that the central portion in the longitudinal axis direction protrudes downward, that is, the light emitting portion 34 side, are attached to the lamp holder 4.
Then, as shown in FIGS. 4 and 5, the correction maintaining member 8 comes into contact with the central portion of the excimer lamp 3 from the lower light emitting portion 34 side, and the excimer lamp 3 is forced to bend by raising it. To maintain a straight line in the longitudinal direction.
In the excimer lamp 3 that has been straightened in the axial direction in this way, the rotation roller 51 at the tip of the movement restricting body 5 provided at the center is in contact with the ultraviolet reflecting film forming portion 35 side at the center thereof. become.
In this case, the excimer lamp 3 and the rotation roller 51 of the movement restricting body 5 may have a gap of about 0.5 mm, for example.
Further, the correction of the curved excimer lamp 3 is not performed by the correction maintaining member 8 but is pushed up from below by a separate pressing means (not shown) to form a straight line, and thereafter the correction maintaining member 8 is contacted. You may make it maintain a linear state.
As shown in FIG. 5, the correction maintaining member 8 is composed of a pair so as to come into contact with both sides of the long side of the excimer lamp 3, and is brought out by contacting with avoiding the electrode 32. It can be used effectively without blocking the incident light, and uneven illuminance on the irradiated object W surface does not occur.

FIG. 6 shows the experimental results of the present invention.
FIG. 6 is a diagram showing the relationship between the lighting elapsed time and the stress (MPa), and there is no bending (conventional example 1), L = 3 mm bending (present invention 1Δ), L = 5 mm bending (present invention 2 ○). ), Stress applied to the entire lamp bent at L = 10 mm (present invention 3 □), and stress (♦) due to ultraviolet distortion alone.
The lamp used in the experiment is an excimer lamp having a flat square arc tube made of quartz glass having a length of 2380 mm, a height of 18 mm, and a width of 71 mm, and xenon is enclosed in the arc tube.
The ultraviolet distortion stress (♦) is a stress value when the lamp is not corrected by being physically pushed and is measured purely by ultraviolet distortion alone. This ultraviolet distortion is accumulated in proportion to the lamp lighting time and reaches 10.3 MPa in 2000 hours and 23.9 MPa in 4000 hours.

The conventional example (■) is a total stress value applied to the lamp when the lamp is not bent. As the lighting time elapses, in addition to the ultraviolet distortion, the upper part, that is, the light emitting part side contracts and warps so that the ultraviolet reflection film forming part side protrudes, so that correction stress is applied by the movement restricting body. . It reached 29.8 MPa in 2000 hours and 49.8 MPa in 5000 hours.
General quartz glass may be damaged when the stress value is 50.0 MPa or more, and the state after 5000 hours in a conventional lamp is dangerous.

The present invention 1 (Δ) is a total stress value applied to a lamp that is bent downward by 3 mm. A certain amount of stress is generated by the correction from the lower side by the central support portion from the lighting initial stage. If this is deformed so as to curve upward as the lighting time elapses, the correction stress from the lower side acts to decrease, and the total total stress temporarily decreases.
The shape protruding downward from the lamp protrudes upward due to the accumulation of ultraviolet distortion, and once becomes a linear shape. At this time, the stress due to the correction is almost negligible, and the stress value due to the ultraviolet stress alone is matched. This is the point where “Invention 1” and “UV stress” lines intersect on FIG.
After that, the correction stress by the movement restricting body is applied by warping upward. Although it reached 18.9 MPa in 2000 hours and 49.1 MPa in 4000 hours, the stress value in the state where the same lighting time has passed is smaller than in the conventional example.

The present invention 2 (◯) is a total stress value applied to a lamp that is bent downward by 5 mm. Also in this case, the same behavior as that of the lamp of the first aspect of the invention is exhibited, and the stress value once decreases at the beginning of lighting and then increases due to the accumulation of ultraviolet distortion.
And it reached 10.4 MPa in 2000 hours and 40.4 MPa in 4000 hours, but in the state where the same lighting time has elapsed, the stress value is smaller than that of the conventional example and even more than the present invention 1. ing.
Invention 3 (□) is a total stress value applied to a lamp that is bent downward by 10 mm. In the case of this lamp, it reached 10.6 MPa in 2000 hours (same as the ultraviolet stress), and reached 33.9 MPa in 4000 hours. It has become.

As described above, according to the present invention, when the excimer lamp is mounted on the excimer light irradiation apparatus by bending the excimer lamp so that the light emitting portion side on which the ultraviolet reflecting film is not formed protrudes, Since the curve is straightened and mounted, the mechanical stress due to this correction is applied in the opposite direction to the stress due to the restriction of the movement restricting body, and this initial stress is relaxed and reduced at the beginning of lighting. The warpage restricting stress by the movement restricting body is accumulated after a predetermined time has elapsed.
That is, a negative stress is initially applied, and this acts so as to gradually become 0 when the lamp is turned on, and then works positively.
Therefore, the same stress standard is reached as compared with the case where the warpage regulating stress that regulates deformation due to ultraviolet rays increases from the beginning as in the conventional example, that is, when it works immediately positive from the initial zero. Thus, it is possible to lengthen the time until the lamp is operated, thereby extending the life of the lamp.

DESCRIPTION OF SYMBOLS 1 Excimer light irradiation apparatus 2 Case 3 Excimer lamp 31 Light emission tube 32 Electrode 33 Ultraviolet reflective film 34 Light-emitting part 35 Ultraviolet reflective film formation part 4 Lamp holder 5 Movement control body 51 Rotating roller 6 Conveying roller 8 Correction maintenance member W Processed object

Claims (3)

A long arc tube having a sealed space made of translucent glass and enclosing a rare gas therein, and a pair of counter electrodes disposed on the outer surface of the arc tube and facing each other with the arc tube interposed therebetween In an excimer lamp comprising an ultraviolet reflecting film formed on the inner wall surface excluding the light emitting portion of the arc tube,
An excimer lamp, wherein a central portion of the arc tube in the tube axis direction is curved so as to protrude in a direction of a light emitting portion of the arc tube.   The excimer lamp according to claim 1, wherein the arc tube has a rectangular cross section perpendicular to the tube axis. An excimer light irradiation apparatus comprising a housing and an excimer lamp held separately from the housing on the lower side of the housing,
The excimer lamp is an excimer lamp according to claim 1 or 2, wherein the casing is provided with a movement restricting body that comes into contact with the ultraviolet reflective film forming portion side at the central portion of the excimer lamp, and from the light emitting portion side. An excimer light irradiating apparatus comprising a correction maintaining member that abuts, wherein the excimer lamp is linearly corrected and held in the tube axis direction by the correction maintaining member.

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