JPS5849689A - Production unit for crystal substrate - Google Patents

Abstract

PURPOSE:The titled device for pulling up a wide ribbonlike crystal, wherein a crystal melt is fed from pockets attached to the both ends of a bridge-shaped heater having wetting properties to the crystal melt to a channel set on the top of the heater and a seed crystal is brought into contact with the melt. CONSTITUTION:The die 11 is heated by applying electricity, a solid raw material consisting of Si powder is fed to the pockets 15a and 15b at its both ends, melted, and a crystal melt is prepared. The crystal melt is made to flow in the channel 14 by the wetting properties of the die 11, and the channel 14 is filled with it. In this state, a seed crystal is brought into contact with the crystal melt at the top channel part 14 of the bridge part 13, the seed crystal is pulled up at a fixed speed, and a crystal is grown under the seed crystal. In growing crystal, its size is restricted by the top size of the channel 14, consequently a ribbonlike crystal is prepared. Therefore the desired wide ribbonlike crystal substrate can be easily made by lengthening the channel 14.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a crystal substrate manufacturing apparatus useful for manufacturing semiconductor substrates for solar cells.

Recently, the demand for solar cells has increased, and it is desired to inexpensively manufacture wide band-shaped crystal substrates that serve as substrates for solar cells. However, this type of band-shaped crystal substrate has conventionally been generally manufactured using the apparatus shown in FIG. This device consists of 4 pieces of quartz heated by a heater 1.
A silicon melt 3 is accommodated in the silicon melt 3, the lower part is immersed in this melt 3, and a predetermined slit is formed to stop the valve through the slit of a pair of capillary dies 4a and 4b arranged facing each other. A belt-shaped crystal substrate 5 is obtained by blending seed crystals as shown in the figure into the melt 3 and pulling the seed crystals under predetermined temperature conditions and at a predetermined speed. The width of the crystal substrate 5 manufactured by this apparatus is, in principle, regulated by the width of the tips of the capillary dies 4a, 4b.

However, in order to widen the width of the band-shaped crystal substrate 5 to meet the above requirements, it is necessary to widen the widths of the dies 4a and 4b, a large-diameter quartz rug 2 is required, and the equipment is large. Take shape. Furthermore, the heating capacity of the heater 1 must also be increased, which increases its power consumption. There were problems in terms of this bundling, the high production cost of the band-shaped crystal substrate 5, and the industrialization of Taiyo Usuiike production.

The present invention has been made in consideration of these circumstances, and its purpose is to provide a practical method for manufacturing a wide band-shaped crystal substrate, which is ideal as a substrate for solar cells, at low cost and with good mass production. An object of the present invention is to provide a manufacturing apparatus for a highly crystalline substrate.

The outline of the present invention is to provide a groove on the upper surface of a bridge-shaped heater that has wettability to the crystal melt, and to melt the solid raw material through grooves that communicate with the groove and are provided at both ends of the heater. By supplying a crystalline melt and pulling up the melt that has been adapted to the seed crystals in the groove, a wide band-shaped crystal substrate is grown there, thereby effectively achieving the above-mentioned purpose. It is.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a perspective view of a main part showing a schematic structure of the apparatus according to the embodiment, and FIGS. 3(a) to (c) are views showing the structure of a die which is a component of the mounting part.

The die 11 is made of a material that is wettable with silicon melt, such as carton, and has flat plate portions 12a and 12b at both ends.

It has a general structure in which two parts 12b are connected by a bridge body part 13. That is, the bridge body portion 13 has a shape similar to that of a rod-shaped body with both ends bent downward, and the flat plate portions 12 a and 72 b are integrally provided at right angles to the lower ends of the bent pieces. . The upper part of the longitudinal side surface of the rod-shaped body forms an inclined surface forming an acute angle with the upper surface thereof. A groove 1 is formed on the top surface of the rod-shaped body that is the top of these slopes.
There are four predetermined widths and depths. This groove 14 is formed along the wall surface of the bent piece in the flat plate part 12g.
, 12b are provided with crystal melt charge pockets 1-15a, respectively.

15b. Charge pocket 15h, 1
Reference numeral 5b denotes a supplementary edition of the bridge body portion 13 of each of the flat plate portions 12h and 12b, which is provided on the upper surface of each flat plate portion 12h. It melts and stores it. The flat plate portions 12a and 12b are provided with screw holes 17a and 17b, respectively.
a, screw 18 & inserted through 17b.

18b are fastened and fixed to electrode terminals 19a and 19b of the power source, respectively. These electrode terminals 19a, 19b are connected, for example, from the flat plate part 12m to the bridge body part 13, and then to the flat plate part 1.
A predetermined current is passed through the die 2b to heat the die 11. Tsumashi, this die 11 is overall 1
It forms two heaters. The groove 14 is formed on the upper surface of this heater, pockets 15m at both ends thereof,
15b.

Thus, according to the present device having such a structure, the die 11 is electrically heated and the pockets 15a, 15 at both ends thereof are heated.
When a solid raw material made of silicon powder is supplied to b, the raw material is heated and melted to become a crystalline melt. Then, due to the wettability of the die 11, the silicon melt permeates into the groove 14 and fills the groove 14. In this state, the seed crystal is blended into the crystal melt in the groove 14 on the upper surface of the 5-bridge body part 13, and the seed crystal is pulled up at a predetermined speed, thereby growing a crystal under the seed crystal.

The shape of the grown crystals is regulated by the size of the groove 14 on the upper surface of the bridge body 1a, and therefore becomes a band-shaped crystal. Therefore, by increasing the length of the grooves 14, it becomes possible to easily manufacture a desired wide band-shaped crystal substrate. In addition, the pocket 15 that decreases as this band-shaped crystal grows.
a.

The crystal melt in 15b is the same as in 15a.

15b can be replenished by continuously feeding solid feedstock. Therefore, it becomes possible to continuously grow the band-shaped crystals.

Also, unlike the conventional device shown in Figure 1, this device uses quartz lubrication. does not require. Therefore, even if it is difficult to grow a wide band-shaped crystal by increasing the length of the groove 14, the other device components do not become larger, and the overall device can be made compact. Moreover, even if the groove 14 is lengthened in this way, the power supply capacity for heating the die 1 by electricity will not increase by much. Still pocket 15a.

Since 15b is incorporated into the die 11, that is, on the heater, the heating energy can be used effectively, resulting in energy savings.

Incidentally, when growing the above-mentioned band-shaped crystals, it goes without saying that the pulling speed of the yuzu crystals and the temperature of the crystal melt should be controlled to the daylight temperature.

By the way, in the structure of the die 11 shown in FIGS. 3(a) to 3(c), the dimensions of each part were set as shown below to grow a band-shaped crystal.

a = 140 (agony), b = 30 (m)c
-5 (throat), d = 5 (japanese) e = 1.5 (mm), f = 0.5 (
mm) g = 1.5 (key), θ = 300 When a die with these dimensions was heated with electricity, there was a difference of 0 between the resistance of the die and the resistance when the crystal melt was supplied.
．． It was confirmed that a resistance value change of 1 to 0.040 occurred. Therefore, it is possible to first sufficiently heat the die 11 to a predetermined temperature, and then gradually supply the silicon raw material to the pockets 15&, 15b while changing the heating storage to stabilize the crystal melt temperature at a predetermined value. desirable. Furthermore, since the amount of melt decreases as the crystal grows, it is desirable to continuously supply the silicon raw material, thereby stably and accurately controlling the temperature. Under these control conditions, this device has a width of 75 columns and a length of 101,000 W.
It was confirmed that a very good strip crystal substrate for solar cells with a thickness of 0.5 ran could be manufactured.

Comparing the features of this device explained above with a conventional device for growing band-shaped crystals with the same specifications, we found that first, the device configuration is simple, and the size can be reduced to about 1/3, making it compact. . In addition, the results showed that the heater heating power could be reduced to about 1/10. Furthermore, the cost of the device can be significantly reduced, resulting in tremendous effects such as lower manufacturing costs.

Note that the present invention is not limited to the above embodiments. For example, the shape and dimensions of the die, the depth of the groove, etc. may be determined according to the specifications, and in short, the present invention can be practiced with various modifications without departing from the gist thereof.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing an example of a conventional device, Fig. 2 is a perspective view of the main part of the device showing an embodiment of the present invention, and Fig. 3 (,)
-(c) are diagrams showing the configuration of a die in the same example. J1...Die, 12a, 12b-flat plate portion, 13...Bridge-shaped body, 14...Groove, 15. h, 15b
...Charge pocket, 16a, 16b...Raw material supply pipe, 17a, 17b...Screw hole, 18 a r 1
8 b = Screw, 19a, 19b... Electrode terminal. Applicant's representative Patent attorney Takehiko Suzue 9-1. 'Chief of the Agency Shima [■Haruki-Den. 1. Indication of small matter Patent application No. 1983 (No. 45808 2, title of invention Crystal substrate manufacturing apparatus 3, Relationship with famous cases requiring supplementary market patent applicant (307) Tokyo Shibaura Electric Co., Ltd. 495-

Claims (1)

[Claims] a bridge-shaped heater that has wettability to the crystal melt; a means for heating the heater with electricity; and a heater provided at both ends of the heater for melting the supplied solid raw material and storing it as the crystal melt. a pocket, a groove provided in communication with the upper surface of the heater and the pocket; and a seed crystal is blended into the crystal melt guided from the pocket to the upper surface of the heater through the groove. 1. An apparatus for producing a crystal substrate, comprising a pulling means.