TWI791767B - excimer lamp - Google Patents

Abstract

The object of the present invention is to provide an excimer lamp in which aluminum can be used as a material constituting the external electrodes and damage to the external electrodes can be avoided. The solution is an excimer lamp, which is equipped with a discharge vessel made of a material that transmits ultraviolet rays, and an excimer lamp is provided with an external electrode on the outside of the discharge vessel. It consists of a plurality of conductive wires patterned so as to have a size within a predetermined range, and is made of a material mainly composed of aluminum.

Description

excimer lamp

The present invention relates to an excimer lamp, and specifically, for example, to an excimer lamp in which grid-shaped external electrodes are provided outside a discharge vessel.

At present, excimer lamps are used as photoashing treatment of photoresist in the manufacturing process of semiconductors and liquid crystals, removal of photoresist attached to the pattern surface of the template of the nanoimprinting device, and for liquid crystals. The light source of the optical processing device used in the dry cleaning treatment of glass substrates and silicon wafers, the removal of smear (smear removal) in the printed circuit board manufacturing process, and the light source of ozone generators.

For example, Patent Document 1 discloses that on the outside of a flat box-shaped discharge vessel made of a material with excellent UV transmittance below 200 nm in wavelength, a pair of mesh-shaped electrodes are arranged opposite to each other across the discharge space. excimer lamps.

In this excimer lamp, it is described that a pair of electrodes are formed by, for example, screen printing, and that a metal material such as gold, silver, copper, nickel, chromium, etc. is used as a material for electrode formation.

[Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2012-195058

Then, when forming electrodes by screen printing, the electrode pattern is usually formed using a conductive paste containing metal particles, and then heated and fired at high temperature to aggregate the metal particles and reduce the resistance of the electrode pattern. However, when aluminum particles are used as the metal particles, the aluminum particles are oxidized during the firing process, so the resistance of the formed electrode pattern increases, and there is a possibility that the electrode may be damaged. For this reason, it was previously considered difficult to print electrodes using aluminum.

Also, in the above-mentioned so-called external electrode type excimer lamp, the electrodes are exposed to vacuum ultraviolet rays and ozone generated by irradiation of the vacuum ultraviolet rays. Therefore, actually, as an electrode constituting material, it is currently necessary to use gold, which has oxidation resistance, high resistance to ultraviolet rays, and low electrical resistance, and there is a problem that a desired excimer lamp cannot be manufactured cost-effectively.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide an excimer lamp in which aluminum can be used as a material constituting the external electrodes and damage to the external electrodes can be avoided.

The excimer lamp of the present invention is equipped with A discharge vessel made of materials, an excimer lamp with an external electrode provided outside the discharge vessel, is characterized in that: the external electrode has a size within a predetermined range by inputting each unit volume of the external electrode It is composed of a plurality of conductive lines formed in a pattern, and is made of a material with aluminum as the main component.

In the excimer lamp of the present invention, the numerical aperture of the external electrode is set such that the thickness of the external electrode is 0.08 mm or less, and the input size per unit volume of the external electrode is 22 W/mm ³ or less. And the electrode area of the aforementioned external electrodes is preferable.

Furthermore, in the excimer lamp of the present invention, it is preferable that the numerical aperture of the aforementioned external electrode is 40% or more.

According to the excimer lamp of the present invention, the external electrode is composed of a plurality of conductive wires patterned so that the input per unit volume becomes within a predetermined range, and a paste-like electrode mainly composed of aluminum can be used. Composition materials are used to form the external electrodes, and the resistance of the external electrodes does not increase over time when the lamp is turned on, so that damage to the external electrodes can be avoided.

10: excimer lamp

11: Discharge container

12: Peripheral wall

20: External electrode

21: Conductive thread

22: opening

30: Oscilloscope

31: Voltage probe

32: Current probe

33: Lighting power supply

G: discharge gap

V: discharge space

R: numerical caliber

S: electrode area

t: Thickness of external electrodes

P: input power

W _E : electrode width

L _E : electrode length

P _L : lamp input

P _E : electrode input

[ Fig. 1 ] A perspective view schematically showing the structure of an example of an excimer lamp of the present invention.

[Fig. 2] A schematic diagram for explaining the numerical aperture of the external electrode.

[ Fig. 3 ] A diagram schematically showing an example of a structure for measuring lamp input.

Hereinafter, embodiments of the present invention will be described in detail.

Fig. 1 is a perspective view schematically showing the structure of an example of an excimer lamp of the present invention. The excimer lamp 10 includes a discharge vessel 11 made of a material that transmits ultraviolet rays (vacuum ultraviolet rays) having a wavelength of 200 nm or less, for example. The discharge vessel 11 of this example can be in the shape of a flat cuboid as a whole, and a discharge space V is formed inside.

As a material constituting the discharge vessel 11, for example, silicon glass such as synthetic quartz glass, sapphire glass, or the like can be used.

In the discharge space V, a luminescent gas that forms excimers by excimer discharge is sealed.

As the light-emitting gas, for example, a rare gas such as xenon gas, argon gas, and krypton gas, or a mixed gas of a rare gas mixed with a halogen gas such as bromine, chlorine, iodine, or fluorine, or the like can be used. For example, when xenon gas is used as the light-emitting gas, vacuum ultraviolet rays having a center wavelength of 172 nm can be obtained. Also, when a mixed gas of krypton and chlorine is used, vacuum ultraviolet rays with a center wavelength of 222 nm can be obtained. Furthermore, when a mixed gas of argon and fluorine is used, vacuum ultraviolet rays with a center wavelength of 193 nm can be obtained.

The sealing pressure of the luminescent gas is, for example, 1~100kPa.

On each outer surface of a pair of peripheral wall portions 12, 12 extending along the flat surface direction of the discharge vessel 11, a pair of external electrodes 20, 20 are formed along the The tube axis of the discharge vessel is arranged opposite to each other.

The external electrodes 20, 20 are constituted by a plurality of conductive wires patterned so that the input per unit volume has a size within a predetermined range.

The external electrode 20 of this example is as shown in FIG. The light-transmitting portion is formed by the opening 22 where the conductive line 21 is not formed. In this example, the intersecting conductive lines 21 are orthogonal (the shape of the opening 22 is, for example, a square shape), but the crossing angle of the conductive lines 21 is not particularly limited.

In addition, the external electrode 20 may be constituted by a plurality of conductive wires 21 extending parallel to each other in a linear electrode pattern as shown in FIG. 2( b ).

In the aforementioned excimer lamp 10, the external electrodes 20, 20 are formed of a material mainly composed of aluminum. Specifically, the external electrodes 20 and 20 use a conductive paste (aluminum paste) containing conductive powder mainly composed of aluminum and glass powder, which is coated on the outside of the discharge vessel by, for example, screen printing and then dried. , Those formed by firing.

As mentioned above, for the external electrode 20, the numerical aperture is R[%], the electrode area is S[mm ² ], the thickness is t[mm], and the input power of the excimer lamp 10 is P[ W], the pattern is formed so that the input _PE per unit volume represented by P/[t×S] becomes a size within a predetermined range.

Specifically, for example, the size of the numerical aperture R of the external electrode 20 and the electrode are set so that the thickness of the external electrode 20 is within the range of 0.08 mm or less and the input size per unit volume is 22 W/mm ^{or less} . The size of the area S.

The thickness t of the external electrode 20 is preferably 0.005-0.08 mm, more preferably 0.02-0.05 mm.

In addition, the input _PE per unit volume of the external electrode 20 is preferably set to 0~22W/mm ³ , more preferably 0.1~10W/mm ³ .

By forming the external electrode 20 in such a conditional pattern, as shown by the results of the experimental example described later, even if the external electrode 20 is printed and formed using a material mainly composed of aluminum, the external electrode 20 when the lamp is turned on The electrical resistance does not increase rapidly over time, and damage to the external electrodes 20 can be reliably avoided.

The numerical caliber of the external electrode 20 refers to the ratio of the area of the opening 22 to the unit area of each electrode including the opening 22 . When the electrode pattern of the external electrode 20 is, for example, a lattice as shown in FIG. In formula (1) described later, a is the opening width, and b is the line width of the conductive line 21 .

Formula (1) R=〔a/(a+b)〕 ² ×100

Moreover, when the electrode pattern of the external electrode is, for example, linear as shown in FIG. In formula (2) described later, a is the opening width, and b is the line width of the conductive line 21 .

Formula (2) R=〔a/(a+b)〕×100

The numerical aperture of the external electrode 20 is based on the viewpoint of light extraction efficiency from the excimer lamp 10, for example, 40% or more is preferable, and 60-90% is more ideal.

The size of the opening width a and the line width b of the conductive line 21 can be appropriately set so that the numerical aperture R becomes within the aforementioned numerical range. However, in order to form a uniform electrode pattern to obtain a stable discharge, the opening width a should be For example, it is set to a size within a range of 1 to 4 mm, and the line width b of the conductive wire 21 is set to, for example, 0.4 mm or less, preferably within a range of 0.1 to 0.3 mm.

The electrode area S of the external electrode 20 is not the area of the electrode forming region on the outside of the discharge vessel 11, but the area of the portion on the outside of the discharge vessel 11 that contacts the conductive wire 21. Specifically, the electrode area S [mm ² ] of the external electrode 20 is represented by the following expression (2). In Equation (2) described later, W _E is the width direction dimension (electrode width) [mm] of the electrode formation region, _LE is the tube axis direction dimension (electrode length) [mm] of the electrode formation region, and R is the external electrode 20 numerical caliber [%].

Formula (2) S=W _E ×L _E ×(100-R)/100

The dimension in the width direction (electrode width) W _E of the electrode formation region is, for example, 10 to 80 mm, and the dimension in the tube axis direction (electrode length) L _E of the electrode formation region is, for example, 10 to 3000 mm.

In this excimer lamp 10, by supplying a high-frequency AC power from a high-frequency AC power source between a pair of external electrodes 20, 20, a potential difference is periodically generated between the external electrodes 20, 20, thereby creating a discharge space. Excimer discharges are generated in V. Then, excimers are formed by excimer discharge, and the light emitted from the excimers passes through the discharge vessel 11 and is emitted through the light-transmitting parts (openings 22 ) of the grid-shaped external electrodes 20 .

Then, according to the aforementioned excimer lamp 10, since the external electrode 20 is patterned so that the input _PE per unit volume becomes within a predetermined range, a paste-like electrode mainly composed of aluminum can be used. The external electrode 20 is formed by printing with the constituent materials, and the resistance of the external electrode 20 does not increase rapidly over time when the lamp is turned on, so that the damage of the external electrode 20 can be avoided.

In addition, since cheaper aluminum can be used than gold or the like which is ideally used as a constituent material of the external electrodes in the conventional excimer lamp, the desired excimer lamp 10 can be advantageously manufactured. Furthermore, if it is an external electrode formed by arranging metal wires in a grid shape, there is a possibility that the defect of discharge instability may occur due to deformation of the mesh due to external force. However, according to the above-mentioned excimer lamp 10 In addition, since the external electrodes 20 are made of printed electrodes, such defects can be avoided, and desired electrode patterns can be easily formed. Furthermore, since the external electrode 20 can be formed flat, it is easy to incorporate into a light irradiation device and the like and has excellent handling properties.

As mentioned above, although one embodiment of the excimer lamp of this invention was demonstrated, this invention is not limited to the said embodiment, Various changes can be added.

For example, the method of forming the external electrodes by printing is not limited to the screen printing method. Also, the external electrodes may be formed by drawing and coating electrode constituting materials.

In addition, the excimer lamp of the present invention is not limited to a structure in which a pair of external electrodes are provided on the outside of the flat discharge vessel as described above.

[Example]

Hereinafter, specific examples of the excimer lamp of the present invention will be described, but the present invention is not limited to these examples.

[Example 1]

Referring to the structure shown in FIG. 1 , 15 types of excimer lamps (hereinafter referred to as "lamp tube 1" to "lamp tube 15") equipped with external electrodes (20) having electrode patterns shown in Table 1 below were produced. The material of the discharge vessel (11) is quartz glass, the dimension in the width direction is 36 mm, the dimension in the tube axis direction (full length) is 350 mm, the thickness is 1.6 mm, and the discharge gap (G) is 11 mm. Also, as the luminescent gas, a mixed gas of krypton gas (sealed pressure 10 kPa) and chlorine gas (sealed pressure 0.6 kPa) was used.

The external electrodes ( 20 ) are formed by screen printing using an aluminum paste composed of aluminum and low-melting glass mainly composed of silver, silicon oxide, zinc oxide, and borax.

The thickness of the external electrode (20) was measured using a laser microscope (manufactured by KEYENCE: VK-X150).

By applying an AC voltage of 6-10kVpp, 60-120kHz between a pair of external electrodes (20), the manufactured lamp tubes 1-15 are turned on. Then, the resistance of the external electrode (20) was measured at a time point of 100 hours after lighting the lamp, and the degree of change in the resistance of the external electrode (20) relative to the initial lighting of the lamp was investigated.

The resistance of the external electrode (20) is measured with 4 terminals using a digital multi-purpose meter ("Digital Multi-meter 7562" manufactured by Yokogawa Electric Corporation) and a probe ("Needle Test Lead 9770" manufactured by Hioki Electric Corporation) method to measure.

Expressed as a percentage, the resistance value increase rate [(r1/r0)×100] of the value obtained by dividing the resistance value (r1) after 100 hours by the resistance value (r0) at the beginning of lamp lighting is less than 300% The situation is rated as "○", and the situation of 300% or more is rated as "×". The results are shown in Table 2 below.

The lamp input _PL [W] in Table 2 is a value measured as follows. First, the measurement system shown in FIG. 3 is constructed, and the voltage across the excimer lamp (10) and the current flowing through the excimer lamp (10) are measured with an oscilloscope (30). Then, the obtained voltage waveform is multiplied by the current waveform, integrated for one cycle, and then multiplied by the frequency, thereby measuring the lamp input _PL input to the excimer lamp (10). In FIG. 3 , 31 is a voltage probe, 32 is a current probe, and 33 is a lighting power supply.

As shown in the above results, the external electrode (20) patterned so that the thickness t is 0.08 mm or less and the input per unit volume (electrode input P _E ) is 22 W/mm ³ or less In each of lamp tube 3 to lamp tube 9 and lamp tube 11 to lamp tube 14, it was confirmed that even in the case of using a material mainly composed of aluminum when forming the external electrode (20) by printing, the external electrode (20) ) resistance value will not increase rapidly over time, which can avoid the damage of the external electrode (20).

On the other hand, among lamp tubes 1 to 2, lamp tube 10, and lamp tube 15 with external electrodes (20) patterned in such a way that the electrode input P _E exceeds 22W/mm ³ , it can be confirmed that any of them is due to resistance The value rises sharply, causing the conductive wire constituting the external electrode (20) to be disconnected, and the lamp tube becomes unlit. The cause is presumed to be as follows.

That is, when the lamp tube is turned on, the electrons moving in the external electrodes collide with the aluminum atoms to exchange kinetic energy, thereby causing electron drift in which ions gradually move. It is presumed that when the electrode input _PE exceeds 22W/mm ³ , the amount of movement of ions increases with the passage of time, and the resistance value of the external electrode increases, thereby causing damage to the electrode (disconnection of the conductive wire). Also, as the electrode input _PE becomes larger, the current density also becomes higher, so the amount of electrons moving in the external electrodes also increases. Therefore, it can be presumed that a defect of electrode damage due to electron drift appears remarkably.

10‧‧‧excimer lamp

11‧‧‧Discharge vessel

12‧‧‧peripheral wall

20‧‧‧External electrodes

Claims (2)

An excimer lamp is equipped with a discharge vessel made of a material that transmits ultraviolet rays, and an excimer lamp is provided with an external electrode outside the discharge vessel. It is characterized in that: the aforementioned external electrodes are formed by using each It is composed of a plurality of conductive lines patterned so that the input per unit volume becomes a size within a predetermined range, and is made of a material mainly composed of aluminum; the thickness of the aforementioned external electrodes is 0.08mm or less, and the thickness of the aforementioned external electrodes The size of the numerical aperture of the aforementioned external electrodes and the electrode area of the aforementioned external electrodes are set so that the input size per unit volume becomes 22 W/mm ³ or less. In the excimer lamp as described in claim 1, the numerical aperture of the aforementioned external electrodes is 40% or more.

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