JPS6024549B2 - Heater for melting semiconductors or metals - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heater for melting semiconductors or metals.

For example, in a single crystal pulling apparatus, a resistance heating type cylindrical heater is provided surrounding a crucible containing a semiconductor such as silicon to be melted, and the semiconductor in the crucible is melted by the heating of the heater. is being explored.

By the way, in order to energize this kind of heater,
A method using three-phase alternating current and a method using single-phase alternating current or direct current have been proposed, but these conventional heating methods have the following drawbacks. That is, first, there is a method using three-phase alternating current, but in this case, a molten liquid of a semiconductor such as silicon, heated by a heater, is guided in a fixed direction in a crucible by three-phase alternating current. There is a direction in which the crucible is rotated and is damaged, and when such damage occurs, if the crucible is rotated in the opposite direction, the temperature distribution becomes flat and crystal growth does not occur. If this becomes impossible and rotation in the same direction is applied, the wave effect will be reduced, but the movement of the molten semiconductor in the crucible will become faster, and a wave-making effect will occur between it and the crystal grown from the seed. , and stable crystal growth cannot be expected. On the other hand, methods using single-phase AC or DC can avoid the problems described above when using three-phase AC, but because the heater is supported at two points in the secondary structure, the following problems occur: You will run into problems like this. In other words, if you try to fill a crucible with a large amount of semiconductor and process it,
A large-diameter crucible must be used, and the diameter of the heater must also be increased accordingly.
If a heater with such a large diameter is to be supported at two points as in the past, the support of the heater will inevitably become unstable. In this way, if the support of the heater becomes unstable, it is obvious that, for example, this type of heater is generally energized by a large current.
It is easy to understand that the lifespan of the heater will be shortened and the reliability of the furnace itself will be impaired. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a heater which is energized by single-phase alternating current or direct current, and which can be stably supported even if it is constructed with a large diameter.

Embodiments of the present invention will be described below with reference to the drawings.
Referring first to FIG. 1, a heater according to an embodiment of the present invention is indicated generally by the numeral 1.

In this embodiment, the heater 1 is constructed as a cylindrical body with both ends open, made of any suitable resistive material such as graphite, and the cylindrical heater 1 is inserted into the cylindrical heater alternately from both end faces in the axial direction of the cylindrical heater. Moreover, the slits 2a and 2b are formed in a substantially parallel relationship with each other by extending halfway. Furthermore, on the lower end surface of the heater 1, as shown in FIG. Moreover, the shield is installed parallel to the marker line of the heater. FIG. 3 is an electrical equivalent circuit diagram of the heater shown in FIGS. 1 and 2, with connection points 4a, 4b, 4c and 4d corresponding to the above-mentioned terminals 3a, 3b, 3c and 3d, respectively. , resistances R, , R2, R3 and R4 represent the resistance of the heater itself between each terminal. As shown in FIG. 3, the heater 1 according to the present invention has the terminals 3a to 3d protruding, so that four resistors R, to R4 are connected to each other at the protruding positions of the terminals, respectively, as shown in FIG. It should be noted that a bridge circuit consisting of the following is equivalently formed within the heater. In order to mount the above-described heater of the present invention at a predetermined location, each terminal is attached to the upper end of a water-cooled conductive pipe (not shown) that is stably provided and corresponds to each of the above-mentioned terminals. Just insert it. In this case, for example, these conductive tubes are connected such that the terminals 3a to 3d and therefore the connection points 4a to 4d have the relationship shown in FIG. 3. In this way, the terminals located in a positional relationship facing each other, that is, 3a and 3c, 3b and 3d, are connected to each other, and power supply terminals 5a and 5b are led out from these connection points. Those power supply terminals 5
By supplying single-phase AC or DC power to a and 5b, the heater is energized and generates heat. As can be understood from the above explanation, according to the present invention, since the heating method uses single-phase alternating current or direct current, it is possible to avoid the movement of kudzu liquid in the crucible that would occur when using three-phase alternating current. Moreover, since the heater has a four-point support structure, even if the heater has a large diameter, it can be stably supported.

Thus, it will be understood that according to the present invention, the problems of the secondary technology described at the beginning can be solved all at once.

[Brief explanation of drawings]

FIG. 1 is a side elevational view of a heater according to an embodiment of the present invention;
2 is a bottom view of FIG. 1, and FIG. 3 is an electrical equivalent circuit diagram of the heater of FIG. 1. 1...Heater, 2a, 2b...Slit, 3a to 3d
...Terminal, R, ~R4...Resistance of the heater itself. Younger brother l figure 2 figure 3

Claims (1)

[Claims] 1 A cylindrical heater made of an electrically resistive material, in which four terminals are protruded from the lower end surface of the cylindrical heater at substantially equal angular intervals, and the protruding terminals ,
A bridge circuit consisting of four resistance elements each having connection points at these terminal protruding positions is formed equivalently within the cylindrical heater, and the terminals act as support means for the heater. The four terminals are connected to each other in opposing positions, and heat is generated by supplying single-phase AC or DC current between the connection points. A heater for melting semiconductors or metals, characterized in that the heater is made to melt semiconductors or metals.