JPS61151100A - Heater - Google Patents

Abstract

PURPOSE:A heater that is made by encapsulating electrically heating elements through spacers into a tube resistant to solutions to be used in treatments so that it is supported by the spacer, thus preventing pin-hole formation. CONSTITUTION:In an encapsulation vessel 4 which is made of a material resistant to treating solutions such as etching solution such as a quartz pipe, an electrically heating elements such as nichrome wires 5 which is allowed to pass through spacers 8 such as bored quartz beads is placed and held. Thus, the encapsulation vessel is quite free from forming pin-holes by local heating whereby the treating solution does not come into the vessel 4 to prevent the heating elements and treating solutions from being contaminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a heating technique, and particularly to a technique that is effective when used to heat a chemical solution having an etching action.

When performing cleaning before etching or diffusion on 4-body wafers during the manufacturing process of body devices, phosphoric acid, the so-called U cleaning solution (RCA cleaning solution, ammonia water, hydrogen peroxide solution, etc.) is used as the chemical solution. Etching is performed by using a chemical solution with an etching effect, such as a mixed solution of water, and by heating the chemical solution.

When heating such an etching solution, in order to prevent contamination and corrosion caused by the chemical solution, a nichrome wire as a heating element is enclosed in a quartz pipe and placed in the etching bath.

However, with this heating method, the bottom surface of the nichrome wire inside the quartz pipe is in point contact with the inner wall surface (bottom wall surface) of the quartz pipe under its own weight, so if the nichrome wire generates heat in this state, it will cause the quartz pipe to emit heat. Only the part in contact with the nichrome wire is locally heated and becomes high temperature.

As a result, the outer wall surface of only the heated portion of the quartz pipe is particularly severely etched, and pinholes are generated in that portion. As a result, its pinho++, J-,':'C
No18J+? 7'knee=l-r+X1-1'+++r-
1,9,11-/yMr'tf3, lη of the chemical solution
Produce dyeing. The present inventors have discovered that when the chemical solution is dyed with leta, the object to be processed, such as a semiconductor wafer, which is immersed in the chemical solution and undergoes etching and cleaning, is dyed with leta and generates an etching liquid.

Regarding etching using the wet method,
On April 28, 2015, “Semiconductor/I” published by Ohmsha Co., Ltd.
C terminology dictionary" page 25.

Also, examples that describe techniques for cleaning wafers include:
"Electronic Materials" November 1981 issue, published by Kogyo Research Association Co., Ltd., special edition, November 10, 1981, P95-P10
There are 2.

[Objective of the Invention J An object of the present invention is to provide a technique that can prevent pinholes from being locally etched in an enclosure enclosing a heating element.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[(renovation) of invention]

A brief overview of typical inventions disclosed in this application is as follows.

In other words, by supporting the heating element enclosed within the enclosure made of a material resistant to the processing liquid with a spacer, the enclosure is prevented from being locally heated. This prevents pinholes from being etched.

[Embodiment 1] FIG. 1 (81, (bl) is an enlarged partial sectional view of a heater according to an embodiment of the present invention and its IBIB sectional view, and FIG. 2 is a perspective view showing its usage state.

In this embodiment, the heater 1 is of the so-called immersion heater type, and as shown in FIG. 2, this heater 1 is immersed in the etching solution 3 in the etching bath 2 to heat the etching solution 3. be.

The heater 1 consists of a quartz pipe 4 (enclosed body) made of quartz so as not to be corroded by the etching liquid 3, and nichrome cotton 5 (heating element) sealed in the quartz pipe 4. The inlet portion is sealed with a sealing plug 6, and a power supply line 7 to the nichrome wire 5 is led out through this sealing plug 6.

The nichrome wire 5 is wound into a coil inside the quartz pipe 4 as shown in FIG. The nichrome wire 5 is supported on the bottom inner wall surface of the quartz pipe 4 via the spacer 8. Therefore, in this embodiment, The nichrome wire 5 is not in direct contact with the inner wall surface of the quartz pipe 4.

As a result, in this embodiment, even if the nichrome wire 5 is heated to a high temperature by applying electricity to the nichrome wire 5 in order to heat the etching solution 3 in the etching tank 2, the quartz pipe 4 is locally heated to a high temperature. This will prevent it from happening.

As a result, the outer wall surface corresponding to the high temperature portion of the quartz pipe 4 is subjected to an etching action due to the local high temperature/crystallization of the quartz pipe 4, and the generation of pinholes is finally suppressed. As a result, the etching liquid 3 is prevented from penetrating into the quartz pipe 4 through the pinhole, causing corrosion of the nichrome wire 5 and contamination of the etching liquid 3.
It is possible to prevent contamination of the liquid (as shown in the figure) and improve yield.

Note that when fitting the spacer 8 of the nichrome wire 5, the end of the nichrome wire 5 is passed through the hole of the spacer 8 and the spacer 8 is inserted.
The nichrome wire 5 can be moved along the length of the nichrome wire 5 to a desired position.

[Embodiment 2] FIG. 3 is a sectional view of a heater which is another embodiment of the present invention.

In this embodiment, the heating element is made of a plate-shaped plate heater 15, and the enclosure is constructed as a sealed box 14 by bending a quartz plate. And plate heater 1
5 is a quartz round bar 18 welded to the inner wall surface of the sealed box 14.
It is enclosed and supported within the sealed box 14 via a spacer.

In this embodiment as well, the quartz round rod 18 as a spacer is used.
The presence of the plate heater 15 prevents the sealed box 14 from becoming locally heated when the plate heater 15 generates heat, thereby extending the life of the heater.

〔effect〕

(1) The heating element is enclosed and supported via a spacer in the enclosure made of a material resistant to processing liquids, so that the heating element does not come into direct contact with the enclosure and the enclosure is heated. It is possible to prevent pinholes from occurring due to localized high temperatures, and to extend the service life.

(2) The fil prevents the processing liquid from entering the enclosure, thereby preventing contamination and corrosion of the heating element.

(3) According to (2) above, it is possible to prevent contamination of the processing liquid by the heating element, thereby preventing contamination of the object to be processed in the processing liquid and improving the yield.

(4). Due to the above (3), when the object to be processed is an object that requires extremely strict cleanliness, such as a semiconductor wafer, an extremely shape-retaining effect can be achieved.

(5) By constructing 1 heating element with nichrome wire and fitting the spacer so that it can be moved and supported on the nichrome wire, direct contact between the heating element and the enclosing body is prevented, The effects (1) to (4) above can be achieved.

Moreover, as an economical effect, in the present invention, if the nichrome wire breaks, it can be repaired by replacing parts except for the most expensive quartz enclosure, which is economical. On the other hand, heaters in which magnesium oxide or the like is filled between the nichrome wire and the enclosure, as seen in sheath heaters, cannot be repaired and are expensive.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, the structures of the heating element, the enclosure, the spacer, etc. may be different.

In addition, the material of the inclusion body and spacer may be other than quartz, such as a ceramic material that is resistant to processing liquid, but it is recommended that the inclusion body and spacer be made of materials with similar coefficients of thermal expansion. preferable.

[Application field]

In the above explanation, the invention made by the present inventor was mainly applied to the field of application, which is the field of application, which is a heater for etching or cleaning semiconductor wafers, but the present invention is not limited to this, for example, It can be widely applied to heaters used to heat processing liquids that have an etching effect or the like.

Brief explanation of page 1 Fig. 1 (a), (bl is an enlarged partial sectional view of a heater that is an embodiment of the present invention and its sectional view taken along the line IB-1, and Fig. 2 is a perspective view showing its usage condition) FIG. 3 is a sectional view of a heater which is another embodiment of the present invention.

1... Heater 1. 2... Etching tank, 3... Etching liquid, 4... Quartz pipe (inclusion body), 5...
2〃ROM (regular output) fl,, life sealing plug, 7... power supply line, 8... spacer, 14... sealed box (inclusion body)
, 15... Plate heater (heating element), 18... Quartz round bar (spacer).

Claims (1)

[Claims] 1. A heater used by being immersed in a processing liquid,
A heater characterized in that a heating element is enclosed and supported via a spacer in an enclosure made of a material resistant to processing liquids. 2. The heater according to claim 1, wherein the heating element is made of a nichrome wire, and the spacer is a perforated member movably fitted onto the nichrome wire. 3. The heater according to claim 1, wherein the heating element is a plate-shaped heater, and the spacer is a quartz member provided on the inner wall of the enclosure.