JPH0736354U - Flat electrodeless discharge tube - Google Patents

Abstract

(57) [Abstract] [Purpose] A plate-shaped electrodeless discharge tube that increases the mechanical strength of the discharge tube by reducing the stress applied to the periphery of the plate-shaped electrodeless discharge tube, is less likely to be damaged, and is lightweight. To get [Structure] One or a plurality of glass columns are provided in a space formed by welding the peripheral portions of two glass plates facing each other through a glass frame.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a structure of an electrodeless discharge tube for obtaining far-ultraviolet light used in a photoexcitation process.

[0002]

[Prior art]

 The discharge tube used in the electrodeless light source device has a flat plate shape. This uses the light emitted from the discharge tube to clean and modify the surface of the irradiated object of a certain size. In this case, the flat discharge tube is installed parallel to the treated surface of the object to be irradiated, so that the irradiation is uniform and the finish is uniform.

The size of the discharge tube used is slightly larger than that of the object to be irradiated, and the end portion of the object to be irradiated has the same irradiation intensity as that of the central portion.

However, in the field of photo-cleaning that decomposes and removes organic contaminants on the surface of glass and resin, and in the field of surface modification that improves the wettability of the surface coating and the adhesion of the vapor-deposited film, etc. The size of the target has become larger, and currently, silicon wafers for semiconductors and the like are dominated by 6 to 8 inches. The flat plate discharge tube must also be sized to fit this.

FIG. 3 shows a perspective view of a conventional flat plate discharge tube, and FIG. 4 shows a structural view thereof. The structure is such that two glass plates (quartz plates) a and b are arranged so as to face each other, and a glass (quartz) frame c is sandwiched between the peripheral parts by frit glass and the peripheral parts are heated by a furnace. Welded and sealed container. In other words, the discharge space is formed by combining two quartz plates with a frame body therebetween, and keeping a slight gap between the quartz plates.

In addition, a small amount of mercury and a rare gas or halogen-containing gas of 100 torr or less are selected and enclosed in the discharge tube.

Reference numeral d denotes a quartz branch tube provided to control the mercury vapor pressure in the discharge tube during lighting. This branch pipe is inserted into a metal ring, and the metal ring is fixed to a metal water cooling board for temperature adjustment.

[0008]

[Problems to be solved by the device]

 As described above, the flat discharge tube corresponds to the size of the object to be irradiated and needs to be manufactured slightly larger than this. A small amount of mercury and a rare gas or halogen gas of 100 torr or less are selected and filled in the discharge tube. However, due to the pressure difference between the filled gas in the discharge tube and the atmosphere, the quartz plate forming the discharge tube is inside. Receives the force to be crushed. However, since the peripheral portion is fixed by welding, bending stress is eventually generated, and distortion occurs in the quartz plate and the peripheral weld portion.

As an example, when the quartz plate is 8 × 8 inches square, the force received is about 370 kg. This distortion was stronger in a discharge tube with a larger size, and sometimes the discharge tube was damaged. In order to solve this problem, the thickness of the quartz plate has conventionally been increased, but this has been a factor that increases the cost and weight of the discharge tube.

Therefore, it is necessary that the discharge tube has a structure that can withstand this stress strain without increasing the thickness of the quartz plate and that takes into consideration the mechanical strength so that strain does not easily occur at the welded portion.

[0011]

[Means for Solving the Problems]

 One or a plurality of columns are provided between the wall of the discharge tube facing the object to be irradiated and the tube wall facing the inside of the flat plate discharge tube. The stanchions are welded to one pipe wall and in close contact with the other pipe wall.

[0012]

[Action]

 Inside the flat plate discharge tube, several columns are provided between the discharge tube wall facing the irradiated body and the tube wall facing it, and the discharge tube is generated inside due to the pressure difference between the inside and outside of the discharge tube. By carrying the force of crushing with this support, the stress applied to the peripheral edge of the discharge tube can be reduced and the strain can be eliminated.

[0013]

【Example】

 FIG. 1 is a perspective view showing the inside of a flat plate electrodeless discharge tube according to the present invention. The broken line indicates the discharge space and the columns provided inside.

The difference from the conventional flat plate discharge tube is that in the discharge tube structure, some columns are provided between two quartz plates. FIG. 2 is an enlarged cross-sectional view of a column mounting portion of a flat plate electrodeless discharge tube according to the present invention, and a top perspective view thereof. a and b are quartz plates, and e is a pillar.

In the present invention, the force to crush the discharge tube caused by the pressure difference between the pressure inside the discharge tube and the atmosphere is pushed back from the inside according to the law of action and reaction, and the stress applied to the quartz plate and the peripheral weld To reduce the distortion.

As a result, the discharge tube is less likely to be damaged. Since a thin quartz plate (glass plate) can be used, the plate-shaped electrodeless discharge tube is lightweight and inexpensive.

In the embodiment, one end face of the column is welded and fixed to the pipe wall, and the other end face is in close contact with the pipe wall. This can be done by directly applying the burner flame to the welded part when welding the support to one quartz plate, but when covering the contact part with the support by covering the welded part with the quartz plate. This is because heating must be performed through the combined quartz plate. In such a case, it is difficult to obtain sufficient temperature for the fused connection of quartz glass, the contact part does not completely fit and becomes an incomplete welded state, and on the contrary, the force supported by the column makes it necessary for glass. The above force may be applied.

In the above embodiment, as the material of the discharge tube, only the glass plate b on the treated surface side of the object to be irradiated is made of synthetic quartz, and the other glass plate a, the frame body c, the pillar e, and the branch pipe d are used. It was made of fused quartz. Here, the synthetic quartz means quartz produced from silicon halide as a raw material, and the fused quartz means quartz produced by melting silicic acid anhydride or quartz. Compared with fused silica, synthetic quartz is superior in its short-wavelength light transmission required for photocleaning and photomodification, but it is expensive and the discharge tube is different. This is a factor that increases costs. If a material like this example is adopted, the synthetic quartz part can be reduced without lowering the irradiation intensity, and a cheaper flat plate electrodeless discharge tube can be obtained. It does not matter if it is made of quartz.

Further, in the above embodiment, the discharge space is formed by the two flat glass plates and the frame body. However, one or both of the two glass plates facing each other has the peripheral edge protruding portion. With a tray-shaped glass plate, the discharge space can be formed without using a frame. Of course, even in this case, it is possible to reduce the cost by making only the glass plate on the processed surface side of the irradiated object from synthetic quartz.

Further, the shape of the glass plate is not limited to the quadrangle as shown in the figure, and may be circular or polygonal in consideration of the shape of the irradiated body.

[0021]

[Effect of device]

 As explained above, the flat plate electrodeless discharge tube of the present invention pushes inward between the quartz plate (glass plate) facing the object to be irradiated and the quartz plate facing it by the pressure difference inside and outside the discharge tube. It was possible to reduce the stress applied to the periphery of the discharge tube by providing some columns to support the quartz wall against the force of crushing. As a result, the discharge tube has increased mechanical strength, is not damaged, and is lightweight and inexpensive.

Furthermore, by making only the glass plate on the treated surface side of the irradiated object from synthetic quartz and the remaining part from fused silica, the synthetic quartz part can be reduced without lowering the irradiation intensity. It has become possible to provide a less expensive flat plate electrodeless discharge tube.

[Brief description of drawings]

FIG. 1 is a perspective view showing the inside of a flat plate electrodeless discharge tube according to the present invention.

FIG. 2 is an enlarged cross-sectional view and a top perspective view of a column mounting portion of a flat plate electrodeless discharge tube according to the present invention.

FIG. 3 is a perspective view of a conventional flat electrodeless discharge tube.

FIG. 4 is a structural diagram of a conventional flat electrodeless discharge tube.

[Explanation of symbols]

 a, b glass plate (quartz plate) c frame body d branch pipe e pillar

Claims (5)

[Scope of utility model registration request] 1. A flat plate-shaped blank, wherein a column made of glass is provided in a space formed by welding peripheral portions of two glass plates facing each other through a frame made of glass. Electrode discharge tube. 2. One or both of the two glass plates facing each other are tray-shaped glass plates having a peripheral projection, and the peripheral parts of the two glass plates facing each other are directly welded to each other. A plate-shaped electrodeless discharge tube, characterized in that a column made of glass is provided in the formed space. 3. A support column, wherein one end face is welded and fixed to one of the glass plates, and the other end face is arranged so as to be in close contact with the inner face of the other glass plate. The flat plate electrodeless discharge tube according to claim 2. 4. Of the two glass plates facing each other, the glass plate facing the treated surface of the object to be irradiated is made of synthetic quartz, and the other glass plate, the frame and the branch pipe are made of fused silica. The flat plate electrodeless discharge tube according to claim 1. 5. The glass plate facing the treated surface of the object to be irradiated, of the two glass plates facing each other, is made of synthetic quartz, and the other glass plate and the branch pipe are made of fused silica. The flat plate electrodeless discharge tube according to claim 2.