JPH02284601A - Method and glass vessel for preventing bumping - Google Patents

Abstract

PURPOSE:To transform ebullient bubbles into stabilized superfine bubbles and to completely prevent bumping by welding a thin sheet cut out from a quartz glass ingot having fine bubbles to the surface of a glass device. CONSTITUTION:The thin sheet 3 is cut out from a quartz glass ingot 1 contg. fine bubbles having 100-500mu diameter at 100-200 units/cm<2> fine bubble distribution density. The sheet 3 is welded to a glass device 2 to provide uniform ruggednesses on the surface. Namely, since the fine bubbles in quartz glass are opened to form the rugged surface, uniform ruggednesses can be surely and easily formed on the surface of the glass device 2 by controlling the sizes and distribution density of the bubbles. Consequently, the ebullient bubbles in the device 2 are transformed into the stabilized superfine bubbles, and bumping can be completely prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the prevention of bumping in cleaning tanks made of quartz glass used in semiconductor processes and cleaning tanks that require high purity. , related to the prevention of bumping in wafer cleaning tanks in semiconductor processes, physical and chemical cleaning tanks, distillers, etc.

[Prior Art] Conventionally, it has been known to prevent bumping in glass containers by placing marbles, zeolite, etc. in the bottom of the glass container, or by welding quartz glass particles to the bottom of the glass container.

Furthermore, Japanese Patent Application Laid-Open No. 62-234554 discloses that the bottom surface of the container is made uneven by using Cicotte Plus 1 to prevent bumping.

[Problem to be solved by the invention] As a result, containers containing marbles, zeolites, etc.
This means that impurities are introduced into the glass container, causing contamination in semiconductor processes that require high purity.

In addition, in cases where quartz glass particles are welded to the bottom of the container, there is a problem in that the quartz glass particles peel off with repeated use and become mixed into the solution or chemical solution in the container.

Furthermore, in cases where the bottom surface of the container is uneven, it is not easy and troublesome to form the unevenness uniformly.

[Means for solving the problem] The above problem is solved by cutting out a thin plate from a quartz glass ingot having microbubbles (microbubbles), welding this thin plate to a glass device, and providing a --like unevenness on the surface. did.

In addition, by polishing the quartz glass thin plate portion having microbubbles, all the microbubbles were released to the surface side, and fine irregularities were created on the surface.

[Operation] When a liquid reaches a certain temperature under a constant pressure, vaporization begins not only from the surface of the liquid but also from within the liquid. This phenomenon is boiling. When the surface on which the liquid is heated is uneven, local heat concentration occurs on the uneven surface, and the thermal movement of the liquid particles becomes active.As a result, vaporization occurs from each uneven surface and fine bubbles are formed. It is assumed that this will occur.

Therefore, the unevenness on the surface of the fine bubble-filled quartz glass thin plate welded to the bottom of the glass container converts the bubbles associated with the boiling state into fine bubbles, thereby preventing bumping. In addition, since the quartz glass thin plate is completely welded to the bottom of the quartz glass container, it will not peel off during use, and the unevenness on the surface is due to the release of microbubbles, and the size of the microbubbles Since the sheath distribution density can be selected within an appropriate range, the surface can be finished with uniform surface irregularities.

In the generation of microbubbles, the bubbles attached to the uneven portions of the glass surface are first released and become bubble nuclei, and the liquid inside these bubbles further evaporates to form stable fine bubbles. therefore,
If the size of the microbubbles that make up the unevenness is larger than 500 μm, the bubbles generated from inside the liquid will become larger during boiling, and the number of core bubbles will decrease, causing droplets to form on the liquid surface. This defeats the purpose of generating stable fine bubbles and preventing bumping. On the other hand, if it is smaller than 1100 IL, it becomes difficult for bubbles attached to the uneven portions of the glass surface to be released, resulting in an overheated state and a tendency to cause bumping.

Therefore, it is necessary to appropriately control the size of the unevenness, and the size of the microbubbles mixed into the quartz glass is 100 to 50.
0 μm is preferred.

The density of the bubbles is preferably 100 to 200 bubbles/d, and is 1° [Example] Example 1 In FIG. 1, an example in which the present invention is applied to a square barrel made of quartz glass is shown.

First, a quartz glass ingot 1 having fine bubbles is prepared. This ingot 1 has fine bubbles inside. The size of the bubbles is 100 to 500 μm, and the density of the bubbles is 100 to 200 bubbles/cm 2 .

The thickness of this ingot 1 is 1 to 1.5 am, depending on the shape of the quartz glass container 2 in which the bumping prevention device is provided.

Cut with a diamond cutter to a width of 10 to 15 mm.

Let it be thin plate 3. By cutting out the ingot, most of the microbubbles are cut, and the microbubbles are opened on the surface of the quartz glass thin plate, forming a finely uneven surface on the thin plate surface.

Then, pure water and 1 to 2% of anionic surfactant were added to the joint surface of the quartz glass plate material constituting the bottom plate 4 of the quartz glass container 2 and the microfoamed quartz glass thin plate 3 cut out from the ingot into an ultrasonic cleaner. Wash with the solution for 20 minutes at about 30°C. After washing with water, it is immersed in a 5-10% hydrogen fluoride (HF) solution for 10 minutes, further washed with distilled water, and dried.

Next, the thin plate 3 and the quartz glass plate 4 are baked for 3 minutes in a hydrogen flame using air as a combustion aid.

Therefore, a thin plate 3 having fine bubbles is placed on a quartz glass plate 4, and an oxyhydrogen flame is emitted from a burner, and the heating power is gradually increased from the end of the thin plate 3 to complete welding.

This is sufficient to prevent bumping, but if you want to make the unevenness on the surface of the thin plate 3 uniform over the entire surface, mask it with vinyl or paper after cooling, leaving the part of the thin plate 3 that has fine bubbles. and the air pressure is 2 kg.
The surface of the thin plate is polished with silicon carbide fine particles (#30 abrasive grains) at /, ffl. Then, the bubbles near the surface of the thin plate 3 are released on the surface side, and -like unevenness is formed on the surface.

As for the polishing means, the same effect can be obtained not only by sandblasting but also by other means such as grinding with a grindstone.

Further, polishing may be performed in advance before welding the thin plates.

The square barrel shown in the figure is made using the bottom cutout thus obtained.

When this square barrel was heated with an electric heater, when it reached a boiling state, only fine bubbles were generated from the uneven thin plate part, but no bumping occurred.

Example 2 Next, an example of application to a heater tube will be explained with reference to FIG.

On the surface of the circular heater tube 5, a thin plate 3 is cut out from the microfoamed quartz glass ingot 1 in the same manner as in the previous embodiment.
Perform ultrasonic cleaning. and.

When the thin plate 3 is placed on the surface of the heater tube 5 and an oxyhydrogen flame is applied, the thin plate 3 is softened by heat, bent to match the curved surface of the heater tube 5, and then welded. Next, masking is performed in the same manner as in the previous embodiment, and only the surface of the thin plate 3 is polished by sandblasting to release air bubbles near the surface and form a uniform uneven surface on the surface.

When pure water was heated using this heater tube 5, as in the previous example, when it reached a boiling state, fine bubbles were generated from the thin plate 3 having an uneven surface, but no bumping occurred. This heater tube made it possible to heat the liquid without causing bumping.

[Effects] As described above, according to the present invention, the microbubbles of quartz glass are released to form an uneven surface on the surface. It has become possible to reliably and easily obtain various irregularities, convert boiling bubbles into stable generation of extremely fine bubbles, and completely prevent bumping.

In addition, since the thin plate with microbubbles is completely welded to the surface of the glass equipment, there is no possibility of it peeling off during use, unlike conventional bumping prevention devices.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example in which the present invention is applied to a square barrel. FIG. 2 is a perspective view showing an example in which the present invention is applied to a heater tube. 1: Quartz glass ingot with microbubbles 2: Quartz glass container 3: Thin plate 4: Bottoming of quartz glass container 5: Heater tube M 1 Figure Patent applicant Nippon Quartz Glass Co., Ltd.

Claims (4)

[Claims] (1) A bumping prevention method characterized by welding a thin plate cut from a quartz glass ingot having microbubbles to the surface of a glass device. (2) The bumping prevention method according to claim 1, wherein the diameter of the microbubbles is 100 to 500 μm, and the distribution density of the microbubbles is 100 to 200 pieces/cm^2. (3) The method for preventing bumping according to claim 1 or 2, in which only the portion of the thin silica glass plate having microbubbles is polished to release the microbubbles on the surface side. (4) A quartz glass container in which a thin quartz glass plate in which microbubbles with a diameter of 100 to 500 μm, which are open to the surface side, are distributed at a distribution density of 100 to 200 pieces/cm^2 is welded to the bottom surface.