JP3122476U - Sealing structure of the end of a sheath heater for a disk-shaped wafer heating device - Google Patents

Abstract

To prevent a reduction in the degree of vacuum in a chamber due to a crack in a metal tube of a sheath heater.
SOLUTION: At the end of a sheath heater inserted into a disk-shaped portion of a disk-shaped wafer heating apparatus that performs chemical vapor deposition processing by heating a wafer adsorbed on the upper surface, the length is intermediate between a metal tube 233 and a heating wire 231. The heat-resistant rubber 235 is filled over 20 to 30 mm to improve the sealing performance.
[Selection] Figure 1

Description

  According to the present invention, in the manufacturing process of a semiconductor wafer such as a silicon wafer, an end of a sheath heater inserted into a disk-shaped portion of a disk-shaped wafer heating apparatus that performs chemical vapor deposition (CVD) by heating the wafer adsorbed on the upper surface. The present invention relates to a sealing structure.

In the manufacturing process of silicon wafers and the like, chemical vapor deposition is performed by adsorbing a wafer as a material on the upper surface of a disk-shaped wafer heating device (also referred to as a susceptor) in a vacuum chamber and heating the wafer.
A chemical vapor deposition apparatus described as “conventional technology” in Patent Document 1 will be briefly described with reference to the drawings.

FIG. 3 is a cross-sectional view showing an example of a chemical vapor deposition apparatus. 1 is a vacuum chamber, 11 is a gas supply hole for supplying gas into the vacuum chamber, 12 is an exhaust hole, 2 is a disk-shaped wafer heating device, and 21 is a disk. Shaped plate-like body, 22 is a cylindrical body supporting the plate, 23 is a resistance heating element, 24 is its power supply terminal, 25 is a lead wire, 26 is a temperature detection means such as a thermocouple, 27 is its lead wire, W is It is a wafer.
In this chemical vapor deposition apparatus, the inside of the vacuum chamber is depressurized by a vacuum pump (not shown), while a reaction gas of a film component is supplied into the vacuum chamber, and a desired surface is applied to the surface of the wafer W adsorbed on the plate-like body 21. A film is formed. In the case of plasma chemical vapor deposition, a voltage is further applied to the vacuum chamber to cause plasma discharge. The plate-like body 21 and the cylindrical body 22 are made of metal such as stainless steel or aluminum alloy, or ceramic.

A sheath heater is often used as the resistance heating element. The sheath heater is a tubular heater that is manufactured by putting a resistance heating wire in a metal sheath (pipe), filling a gap with an insulator such as magnesia (magnesium oxide) at a high density, and rolling. By rolling the whole after filling with the insulator, the heat conduction of the insulator is increased, and the temperature difference between the heating wire and the metal is reduced. The outer diameter of the metal sheath is, for example, 12 mm, and the tube thickness is 1 mm.
JP 2001-237051 A

  FIG. 4 is a cross-sectional view showing a main part of a conventional chemical vapor deposition processing apparatus in which the disk-shaped wafer heating apparatus 2 is made of metal and a sheath heater is used as a resistance heating element. The plate-like body 21 has two metal plates 21a and 21b welded all around at the end face position indicated by symbol A, and a sheath heater 23 is embedded in the mating surface of the two metal plates 21a and 21b. By the way, the disk-shaped wafer heating apparatus 2 repeats high-speed temperature rise and high-speed temperature decrease from room temperature to a high temperature of about 300 degrees in the operation cycle. Cracks are likely to occur. The leading part of the generated portion is a welded portion indicated by a symbol A. Even if some cracks are generated, the chemical vapor deposition process is not immediately disabled. However, if cracks are generated from this, and if the sheath heater also cracks, the airtightness in the vacuum chamber is impaired, and the vacuum chamber passes through the sheath heater. There is a problem that the quality of chemical vapor deposition deteriorates due to the intrusion of air into the interior. Incidentally, the structure of the conventional sheath heater end is shown in FIG. 231 is a resistance heating wire, 232 is magnesia, and 233 is a metal sheath. Although a sealing resin 234 is applied in order to suppress peeling of magnesia on the end face, the structure is not sufficiently airtight.

  An object of this invention is to suppress the quality fall of a chemical vapor deposition process by improving the airtightness of this sheath heater edge part.

  In the present invention, at the end of the sheath heater inserted into the disc-shaped portion of the disc-shaped wafer heating apparatus that heats the wafer adsorbed on the upper surface and performs chemical vapor deposition, it is long between the metal tube of the sheath heater and the heating wire. It is a sealing structure at the end of a sheath heater for a disk-shaped wafer heating device, characterized by being filled with heat-resistant rubber over a length of 20 to 30 mm, preferably a metal tube and heating wire behind the heat-resistant rubber filling portion of the sheath heater The sealing structure of the end portion of the sheath heater for the disk-shaped wafer heating apparatus, which is formed by inserting ceramics in the middle.

  According to the present invention, even if a crack occurs in the welded portion of the plate-like body 21 or the metal tube 233 portion of the sheath heater, this does not immediately impair the airtightness in the vacuum chamber, and the quality of the chemical vapor deposition process is reduced. There is an excellent effect that can be suppressed.

  According to the present invention, the powdery magnesia filled in the end portion of the sheath heater is removed over a predetermined length, and the sealing performance can be improved by filling the heat resistant rubber in this portion. Since the heat-resistant rubber is pasty at the filling stage, it can be filled without gaps, and is cured and united after filling.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a sealing structure of an end portion of a sheath heater for a disk-shaped wafer heating apparatus according to the first embodiment. 231 is a resistance heating wire, 232 is magnesia, 233 is a metal sheath, 234 is a resin, 235 is a heat-resistant rubber. It is. That is, the magnesia 232 in the metal sheath is removed over a length of 20 to 30 mm, and instead, heat resistant rubber is filled between the metal tube and the heating wire. It is desirable to apply the resin 234 on the surface as before. The heat-resistant rubber requires 20-30 mm as described above and has a sufficient length.

  FIG. 2 is a cross-sectional view showing the sealing structure of the end portion of the sheath heater according to a modified embodiment, and 236 is ceramics. If the solid ceramic 236 is inserted after the magnesia 232 is removed, the bottom portion is stabilized when the paste-like heat-resistant rubber is filled, and the resistance heating wire 231 is not eccentric. Other parts are the same as those in FIG.

It is sectional drawing which shows the sealing structure of the sheath heater edge part of this invention Example. It is sectional drawing which shows the sealing structure of the sheath heater edge part of this invention modification. It is sectional drawing which shows an example of the well-known chemical vapor deposition processing apparatus concerning this invention. It is sectional drawing which shows the principal part of the chemical vapor deposition processing apparatus in a prior art. It is sectional drawing which shows the structure of the sheath heater edge part in a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Disk-shaped wafer heating apparatus 11 Gas supply hole 12 Exhaust hole 21 Plate-shaped body 22 Cylindrical body 23 Resistance heating element 24 Power supply terminal 25 (For power supply) Lead wire 26 Temperature detection means 27 (For temperature detection) Lead wire 231 Resistance heating wire (heating wire)
232 Magnesia 233 Metal sheath (metal tube)
234 Resin 235 Heat-resistant rubber 236 Ceramic W wafer

Claims (2)

  At the end of the sheath heater that is inserted into the disc-shaped portion of the disc-shaped wafer heating apparatus (2) that heats the wafer (W) adsorbed on the upper surface and performs chemical vapor deposition, the sheath heater metal tube (233) and heating wire ( 231) and a heat-resistant rubber (235) filled in a length of 20 to 30 mm in the middle.   The disk-shaped wafer heating device according to claim 1, wherein ceramics (236) is inserted between the metal tube (233) and the heating wire (231) at the back of the filling portion of the heat-resistant rubber (235) of the sheath heater. Sealing structure at the end of the sheath heater.

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