JPH0569157U - Terminal for fixing heating resistor - Google Patents

Abstract

(57) [Summary] [Purpose] Prevents fusion of the heating resistor and the terminal. Prevents damage to heating resistors. Improving the ultimate temperature by the heat insulation effect. [Structure] The liner made of graphite sandwiches the heating resistor and fixes it to the terminal. In addition, the contact resistance is reduced by forming a groove in the liner, and the occurrence of thermal stress is prevented by matching the direction of thermal contraction. [Effect] Prevents fusion. Prevents damage to heating resistors. And improved thermal efficiency.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a coating device, and more particularly to a terminal for fixing a heating resistor that heats or activates an evaporation source in physical vapor deposition or chemical vapor deposition.

[0002]

[Prior Art]

 In the conventional vapor deposition equipment, a heating resistor made of tungsten or molybdenum is fixed directly to the metal terminal installed in the chamber, and the evaporation heat is used to heat and vaporize the vaporization source by the Jol heat generated by energization. .. In the hot filament method used for vapor phase synthesis of diamond, similarly, a thermal activation filament made of tungsten or tungsten carbide was fixed to a metal terminal for deposition.

[0003]

[Problems to be solved by the device]

 If the heating resistor is fixed directly to the metal terminal as described above, the following problems will occur. First, there is a problem of deformation and cracking of the evaporation boat (filament) due to the thermal expansion of the heating resistor. This is caused by thermal expansion etc. because both ends of the boat are fixed to the metal terminals. Normally, stress is relaxed by fixing the boat (filament) slightly loosely, but problems such as fusion due to sparks due to poor contact at the terminal or power failure may occur.

Next, in the synthesis of diamond by the hot filament method, it is necessary to maintain the exothermic temperature of 2000 ° C. or higher for several hours. In such a situation, there was a problem that the terminal was heated by heat conduction, and fusion with the filament often occurred and the reached temperature was low.

[0005]

[Means for Solving the Problems] In order to solve the above problems, a liner heating resistor (boat, filament) made of graphite was sandwiched, and the liner was fixed to a metal terminal. Further, in order to increase the contact area between the heating resistor and the graphite liner, a groove matching the shape of the heating resistor was formed in the graphite liner. Further, a linear groove was formed in a direction corresponding to the expansion / contraction direction of the heating resistor due to thermal expansion.

[0006]

[Action]

 Graphite is stable and has electrical conductivity even at high temperatures in a vacuum atmosphere or a reducing atmosphere. According to the Chemical Handbook (edited by The Chemical Society of Japan, Maruzen), the thermal conductivity of graphite is about 55 W / m · K at 1000 K, and the high thermal conductivity of 121 W / m · K for tungsten and 112 W / m · K for molybdenum. It is smaller than the melting point metal, and when used as a liner, it has a heat insulating effect and acts as a preventive material for fusion.

Further, by forming a groove in the liner that matches the shape of the heating resistor, the contact area with the heating resistor is increased and the contact resistance is reduced. Furthermore, since graphite acts as a solid lubricant, the grooves of the graphite liner are formed in a straight line and aligned with the direction of expansion and contraction due to the thermal expansion of the heat generating resistor, enabling the slide while maintaining electrical contact. Therefore, thermal stress is not generated on the heating resistor, and stable vapor deposition is realized without deformation or cracking.

[0008]

【Example】

 (Embodiment 1) FIG. 1 schematically shows an example of mounting the evaporation boat in the vacuum evaporation apparatus according to the present invention as a heating resistor. A vapor deposition boat 1 made of tungsten and having a width of 15 mm and a wall thickness of 0.3 mm was sandwiched by a graphite liner 2a and fixed to a fixing terminal 3a. The pair of upper and lower liners each had a width of 15 mm and a depth of about 0. A 1 mm groove 4a is formed. Therefore, even if the boat expands and contracts due to thermal expansion, it slides while being guided by the groove of the liner without damaging the electrical contact, and it is possible to deposit without deforming the shape of the boat before heating. ..

As a comparison with the conventional example, 3 g of silver was vapor-deposited under an ultimate vacuum of about 0.000001 Torr. In the conventional structure in which the boat is fixed with the screw of the terminal, a large amount of bending is generated in the lead 5 portion by one-time evaporation. Due to the curvature, the distance from the object to be vapor-deposited changes, the deposition rate changes, and the boat tilts to cause the melt to move to one side, which prevents uniform vapor deposition. Since the boat after use becomes brittle compared to before heating, it cannot be reused after modifying its shape. It should be noted that, with the terminal fixed, it was fractured when vapor deposition was performed four times in succession. On the other hand, in the vapor deposition using the graphite liner of the present invention, it was confirmed that the lead was not bent and cracked (broken), and vapor deposition was possible 10 times or more.

Since the heating temperature is relatively low in the vapor deposition of silver, the conventional method has no problem in fusing the terminal and the boat. (Example 2) An example of a hot filament method for diamond synthesis will be described. FIG. 2 shows a schematic view of the filament fixing part of the synthesizer. The filament 6 has a diameter of 1. A 5 mm tungsten round bar is used, and both ends thereof are sandwiched by a pair of graphite liners 2b having semicircular round grooves 4b and fixed to the terminal 3b. The circular groove 4b formed in the liner guides expansion and contraction of the filament due to thermal expansion, and maintains electrical contact even when it slides.

A filament heating test was performed for 1 hour in a hydrogen atmosphere (30 Torr) using a power supply device of 2 kVA (10 V 200 A). First, with the conventional structure, the filament was fixed to the terminal with screws and the energization was started. However, it was interrupted because a spark was generated due to poor contact on the way. After lightly polishing the terminal and filament with sandpaper, they were firmly fixed again with screws to turn on electricity. The optical pyrometer measured only a maximum output of about 1900 ° C. After cooling, the filament was broken due to heat shrinkage, and the chucking portion was fused to the copper terminal. Next, a similar test was conducted using the liner of the present invention. At about 80% power, the filament temperature reached about 2000 ° C, which is required for diamond synthesis. Even after cooling, there was no bending of the filament and no fusion between the terminal and the liner and between the liner and the filament. No filament breakage or fusion occurred even in the temperature rising test conducted five times.

In the first and second embodiments, the case of a single line is carried out, but it is possible to supply power to a large number of heating resistors by installing a plurality of similar liners or forming a plurality of grooves. It is self-explanatory.

[0013]

[Effect of the device]

 By making a liner that sandwiches the heating resistor with graphite, which is inexpensive and has excellent workability, the present invention prevents fusion between the terminal and the heating resistor, and also allows expansion and contraction of the heating resistor due to thermal expansion. It has been confirmed that the accompanying stress can be released without impairing the electrical contact, and the effect of extending the life of the heating resistor is extended. Also, since the energy loss due to heat conduction to the terminal is reduced, the effects of improving the heat generation efficiency and increasing the reached temperature are clarified.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a terminal for fixing a heating resistor according to the present invention.

FIG. 2 is an exploded perspective view of a terminal for fixing a heating resistor according to another embodiment of the present invention.

[Explanation of symbols]

 1 Vapor Deposition Boat 2a, 2b Liner 3a, 3b Terminal 4a, 4b Groove 5 Lead 6 Filament 7 Holding Metal 8 Fixing Screw

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Mizuaki Suzuki 6-31-1, Kameido, Koto-ku, Tokyo Seiko Electronics Industry Co., Ltd.

Claims (3)

[Scope of utility model registration request] 1. A heating resistor fixing terminal for fixing a heating resistor used for heating or thermal activation and supplying power in a vacuum or reducing atmosphere, wherein graphite is used between the heating element and the fixing terminal. Terminal for fixing heat-generating resistor, characterized in that a liner is provided. 2. The heating element fixing terminal according to claim 1, wherein a groove for increasing a contact area with the heating resistor is formed on the graphite liner. 3. The groove formed in the graphite liner according to claim 2 is in the same direction as expansion and contraction due to thermal expansion of the heating resistor, and the heating resistor can slide while maintaining electrical contact. The terminal for fixing a heating resistor according to claim 1.