JP3052159B2 - Equipment for manufacturing polycrystalline silicon sheet by cast ribbon method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing a polycrystalline silicon sheet used for solar cells and other photoelectric conversion elements.

[0002]

2. Description of the Related Art Various methods for producing a polycrystalline silicon sheet have already been carried out, and the ribbon method, which is one of the methods, is carried out in an inert gas atmosphere and a crucible a as shown in FIG. The die c is immersed and raised in the existing molten silicon b, and the molten silicon b pulled out from the upper end c ′ of the die c is cooled and solidified in an inert gas atmosphere outside the die c. In the ribbon technology, since the sheet is formed using the meniscus (surface tension) of the molten silicon b, it is difficult to obtain a polycrystalline silicon sheet having a uniform thickness, and as a result, when using it as a device of a solar cell, However, there is a defect that it is difficult to apply the screen printing method even if an electrode is formed on the electrode.

[0003] Further, since the ribbon technology is intended to utilize the wetness with the molten silicon as described above, not only many consumables such as dies, filaments, and substrates are required, but also carbon with good wettability, Since SiC or the like is used, this becomes a source of impurities to the molten silicon. Furthermore, when the ribbon method is used, crystal growth
Growth of the polycrystalline silicon sheet in the drawing direction,
The growth rate of the crystal cannot be so high, and is not satisfactory in terms of quality and production efficiency.

[0004] Also, a so-called casting method (casting method) has been separately practiced. In this method, a silicon base material is heated to form a melt, which is poured into a mold corresponding to the size of a product wafer. Further, the melt is pressed and solidified by the movable part of the mold, and when the same method is used, a wafer of a predetermined shape can be obtained at a time, and although a desirable result in terms of mass productivity can be expected, The melt will be pressed down from all sides as shown. Therefore, in the same method, the upper and lower surfaces and the side surfaces of the mold suppress the growth of silicon crystal grains (grains) when the melt is solidified, and the vicinity of a portion in contact with each surface of the solidified product is very fine. Since large crystal grains cannot be obtained as crystal grains, and it is not possible to satisfy the demand for large crystal grains that is desirable in a silicon wafer for a solar cell or the like, the solar cell obtained by the wafer cannot be satisfied. The photoelectric conversion efficiency is also 2
It has a defect that is extremely bad at 3%.

In order to solve the above-mentioned difficulties, the present applicant has utilized the advantages of the casting method and supplied molten silicon to the mold nozzle. By solidifying the solidified silicon sheet continuously, it is possible to mass-produce a polycrystalline silicon sheet having a uniform thickness without the risk of contamination by impurities, and various thickness dimensions. To make it easier to get
In the device processing step, a method was proposed in which the uniformity of the thickness was not required and the yield was improved (this method is hereinafter referred to as a cast ribbon method).

This method is carried out using a manufacturing apparatus as shown in FIG. 3. In FIG. 3, reference numeral 1 denotes a furnace having an inert atmosphere 1a of an inert gas such as argon or a vacuum. Injection pipe 3 heated by heaters 2a, 2b, etc.
And a mold nozzle 5 heated by the heater 4. The silicon base material charged into the injection pipe 3 is:
After being melted by the heater 2a, the molten silicon Si receives the injection pressure P by an inert gas or the like, and the molten silicon Si is sequentially supplied to the mold nozzle 5 through the supply port 3a of the injection pipe 3 and the injection port 5a of the mold nozzle 5. 5.

Here, as shown in FIGS. 3 and 4, the mold nozzle 5 includes a lower nozzle 5b and an upper nozzle 5c, and a predetermined groove 5d is formed on the upper surface of the lower nozzle 5b. Both parts 5b, 5c with screws that are not
Are fixed in a piled state, or a pressing load is applied as shown by an arrow in FIG. 3 so that a casting path 6 having a predetermined thickness and a predetermined width is formed. Indicates a drawer jig as a drawer.

In order to carry out the above-mentioned cast ribbon method using this casting apparatus, a silicon base material is charged into an injection tube 3 formed of quartz or the like, and the silicon base material is melted (1450 ° C.) by operating a heater 2a. Then, a pressure P (0.01 to 0.1 kg / cm ² ) due to the inert gas is applied to the upper surface of the molten silicon Si. At this time, as shown in FIG. In the direction of the casting path 6 and the drawing end port 5e, the temperature of the casting path 6 is lowered so that the temperature is lowered from a temperature higher than the melting point of silicon (MP = 1420 ° C.) to about 1300 ° C. From the solidified area 5f near the drawing end port 5e toward the drawing jig 7, the temperature is set to be lower than the melting point MP in advance, and into the mold nozzle 5 under such temperature conditions. Of continuously from the inlet 5a, it is adapted to supply the molten silicon Si. As a result, the molten silicon Si is solidified from the gripping end 7a of the drawing jig 7 to the solidified region 5f in the mold nozzle 5, whereby a solidified silicon sheet MSi is formed.

Thus, the solidified silicon sheet MSi
Is formed, the drawing jig 7 is continuously drawn in the direction of the arrow F which is the longitudinal direction of the mold nozzle 5. At this time, the pressure P applied to the molten silicon Si is reduced from the initial pressure described above. It is preferable that the operating pressure is adjusted so that the length of the solidified region 5f does not change. Here, actually, the concave groove 5d has a depth of 0.5 mm and a width of 2 mm.
5 mm is about 250 mm, and carbon is used as a material of the mold nozzle, and its body surface is coated with silicon nitride or coated with Si ₃ N ₄ and SiO _2.
It is used after applying a release material such as a coating of a mixture.

However, in the case of the above-mentioned conventional apparatus, the pressing load W is applied at a required number of places using an air cylinder or the like, and at this time, the pressing load W is, of course, maintained at a predetermined value in an invariable state. Solidified silicon sheet MS
When the pressing load W is large and the pull-out force by the pull-out jig 7 is large, the solidified silicon sheet MSi may be damaged, and the pressing load W is small. And the injection pressure P of the molten silicon Si from the injection pipe 3 is excessive,
There is a defect that molten silicon leaks from a gap between the upper nozzle 5c and the lower nozzle 5b.

[0011]

SUMMARY OF THE INVENTION In view of the drawbacks of the above-mentioned conventional apparatus, the present invention provides a mold nozzle pressing load control section for pressing the upper nozzle and the lower nozzle, and a drawer jig. A withdrawal force control unit attached to the tool, a molten silicon injection pressure control unit for pressurizing the injection pipe, and a control computer, so that these control units have a mutual relationship, whereby It is possible to control the pressing load W by the mold nozzle pressing load control unit in response to the change of the drawing force, and control the injection pressure P of the molten silicon injection pressure control unit based on the embodiment of the pressing load W. By making it possible to control the pressing load W based on the actually measured value of the injection pressure P, the defect of the conventional example as described above, namely, the solidified silicon Damage to the sheet MSi, that molten silicon or accidentally leaked from the gap in the mold nozzle, is at its purpose to try to completely prevent.

According to the second aspect, not only can the object of the first aspect be achieved, but also a pulse counter is attached to the pull-out force control unit, and the output signal is sent to the control computer. By inputting, as programmed in advance in the computer, a predetermined drawing speed and a predetermined pressing load corresponding to the drawing distance are changed, thereby, for example, when starting to pull the solidified silicon sheet from a stationary state Aims to improve the yield of polycrystalline silicon sheets to be produced by automatically operating the ideal withdrawal at a low withdrawal speed and then withdrawing at a high withdrawal speed. That is the purpose.

[0013]

According to the present invention, in order to attain the intended object, the present invention resides in an inert atmosphere, and pressurizes molten silicon in an injection pipe with an inert gas. By continuously feeding this into the heated mold nozzle, the molten silicon is in the casting path of the mold nozzle, and reaches the inside of the gripping end of the drawing jig which is in contact with the drawing end. When the molten silicon in the portion near the drawing end of the mold nozzle is solidified from the gripping end and the pressure is applied to the molten silicon in the injection pipe, the drawing jig is continuously drawn out. By doing, the solidified silicon sheet solidified in the mold nozzle, the apparatus body for performing the cast ribbon method so as to be continuously drawn from the drawing end port,
A mold nozzle pressing load control unit for pressing an upper nozzle and a lower nozzle provided to form a casting path of the mold nozzle, and a pulling force control provided on an unloader shaft connected to the drawing jig. Unit, a molten silicon injection pressure control unit for pressurizing the molten silicon in the injection pipe, and a control computer, the load cell provided in the pull-out force control unit, the pull-out load actual measurement value signal of the measurement is measured. The pressing force is input to the control computer, and the pressing force instruction value signal output thereby causes the pressing force of the load power source of the mold nozzle pressing force control unit to be freely controllable. The load cell provided in the load control unit transmits the measured pressing load actual measurement value signal to the control unit. The injection pressure command value signal output from the computer controls the pressure regulating unit of the molten silicon injection pressure control unit to be controllable, and further measures the pressure by a pressure sensor provided in the molten silicon injection pressure control unit. The known injection pressure measured value signal is input to the control computer, and the pressing load instruction value signal output thereby causes the pressing force of the load power source of the mold nozzle pressing load control unit to be controlled. It is an object of the present invention to provide an apparatus for producing a polycrystalline silicon sheet by a cast ribbon method, wherein the apparatus is controllable.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, a pull-out distance actual measurement signal detected by a pulse counter attached to an unloader shaft of the pull-out force control unit is transmitted to the control unit. The computer controls the computer to input a withdrawal speed instruction value signal and a pressing load instruction value signal that are programmed in advance in accordance with the withdrawal distance, respectively, with the motor controller of the motor for the unloader shaft of the withdrawal force control unit and the mold nozzle retainer. The content is that it is input to the load power source of the attached load control unit.

[0015]

According to the apparatus for manufacturing a polycrystalline silicon sheet according to the first aspect, when the molten silicon which has flowed into the casting path of the mold nozzle by the cast ribbon method becomes a partially solidified silicon sheet as described above, the motor is used. When the pull-out jig is pulled out by, for example, the pull-out load at this time is measured by the load cell of the pull-out force control unit, and the measured pull-out load value signal is input to the control computer.

In this manner, the pressing load instruction value signal transmitted from the control computer controls a load power source such as an air cylinder in the mold nozzle pressing load control unit. The load is automatically reduced, preventing the solidified silicon sheet from being damaged or broken.

In the above-described mold nozzle pressing load control section, the pressing load is also measured by using a load cell, whereby the measured pressing load signal is transmitted to the control computer. The injection pressure instruction value signal which is input and transmitted thereby controls the pressure adjusting unit in the molten silicon injection pressure control unit to change the injection pressure into the injection pipe. As a result, the injection pressure is too large with respect to the pressing load on the mold nozzle, and the fact that molten silicon leaks from the mold nozzle is automatically controlled to an injection pressure corresponding to the value of the pressing load. To avoid.

Further, the injection pressure of the above-mentioned injection pipe due to the inert gas or the like is measured by a pressure sensor such as a dynamic strain gauge, and the measured injection pressure signal is also input to the control computer, based on which. Since the injection pressure instruction value signal controls the load power source in the mold nozzle pressing load control unit, when the injection pressure is large, by increasing the pressing load,
This prevents molten silicon from unintentionally leaking out of the mold nozzle.

According to a second aspect of the present invention, not only the operation of the first aspect, but also a withdrawal distance measurement value signal measured by a pulse counter in the withdrawal force control unit is input to the control computer. The pull-out speed instruction value signal controls the motor controller of the motor for the unloader shaft of the pull-out force control unit because the pull-out speed instruction value and the pressing load instruction value corresponding to the withdrawal distance are programmed in the computer. At the same time, the pressing load instruction value is adjusted to the predetermined pressing load by controlling the load power source of the mold nozzle pressing load control unit. As a result, it is possible to prevent the solidified silicon sheet from being rapidly pulled out at the start of drawing, and to damage the solidified silicon sheet.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiment shown in FIG. 1. An apparatus main body A used for performing a cast ribbon method and a mold nozzle holding member connected to the main body A in the following relationship. It comprises a load control unit B, a pull-out force control unit C, a molten silicon injection pressure control unit D, and a control computer E.

First, the apparatus main body A has substantially the same configuration as the conventional apparatus described with reference to FIGS.
, The same members are denoted by the same reference numerals. Next, the mold nozzle pressing load control unit B includes an upper nozzle 5c and a lower nozzle 5c provided for forming the casting path 6 of the mold nozzle 5. By pressing the nozzle 5b with an external force, the molten silicon Si is prevented from leaking from the gap between the nozzles 5c and 5b.

The drawer force control section C is attached to the unloader shaft A1 connected to the drawer jig 7 in the apparatus main body A, so as to draw out the drawer jig 7 in the direction of arrow F at a desired drawing speed. Things. Further, the molten silicon injection pressure controller D pressurizes the molten silicon Si in the injection pipe 3 toward the casting path 6 of the mold nozzle 5 by pumping the inert gas into the injection pipe 3 of the apparatus main body A. The control computer E performs control based on signals input from the mold nozzle pressing load control unit B, the drawing force control unit C, and the molten silicon injection pressure control unit D. Is transmitted to any of the selected control units as described in detail below.

Here, what is illustrated as the mold nozzle pressing load control unit B is located at three positions in the longitudinal direction of the mold nozzle 5, and the pressing shaft B1 is raised and lowered by a load power source B2 such as an air cylinder. By being movable, the mold nozzle 5 can be pressed, and the load power source B2 is connected to the control computer E by an electropneumatic regulator B4 connected via an indicating controller B3 connected to the control computer E. The pressing load is controlled, and the arrow G in the drawing indicates the air introduced into the electropneumatic regulator B4.

Further, the mold nozzle pressing load control section B includes a load cell B on the pressing shaft rod B1.
5 is provided so that the pressing load can be measured. The measurement result is introduced into the control computer E via the indicator B6 and the indicator controller B3, and the input signal , An instruction value signal for control is output to the molten silicon injection pressure control unit D described later in detail.

Next, the drawing force control section C is provided with an unloader shaft A1 for pulling out the drawing jig 7, and a motor C1 for driving the unloader shaft A1 is controlled by a motor controller C2. Is done. The unloader shaft A1 has a load cell C3.
The pull-out load in the pull-out force control section C is measured, and the pull-out load actual measurement value signal is input to the control computer E, and an instruction value signal for control based on this is described later in detail. As described above, the load power source B2 in the mold nozzle pressing load control section B is controlled.

In the pulling force control section C, the pulling distance of the drawing jig 7 is measured by the pulse counter C4 attached to the unloader shaft A1, and the result is input to the control computer E. The control instruction value signal transmitted based on this signal is configured to control the motor controller C2 and the load power source B2 in the mold nozzle pressing load control unit B according to a predetermined program. , C5 indicates an indicator of the load cell C3.

An instruction value signal from the control computer E is input to the instruction controller D1 in the molten silicon injection pressure control section D as described later in detail, thereby controlling the pressure adjustment section D2 by an electromagnetic valve or the like. Then, the injection pressure of the inert gas or the like in the injection pipe 3 is adjusted. Further, a pressure sensor D3 for actually measuring the inside of the injection pipe 3 is provided, which can input its output signal to the control computer E via the indicating controller D1, and control based on this is performed. Power signal B2 of the mold nozzle pressing load controller B
Are connected to control

Therefore, if the above-mentioned polycrystalline silicon sheet manufacturing apparatus is operated, the solidified silicon sheet MSi is drawn out at a predetermined speed by the draw-out jig 7 based on the previously described cast ribbon method. The pull-out force is transmitted by the pulling of the unloader shaft A1 by the driving of the motor C1.
By 3, a measured pull-out load actual measurement value signal is input to the control computer E.

Based on this, from the control computer E,
The pressing load instruction value signal is transmitted to the indicating controller B3 in the mold nozzle pressing load control unit B, whereby the air G of the electropneumatic regulator B4 is adjusted, and the load power source B2 is controlled by an air cylinder or the like. As a result, the pressing load on the mold nozzle 5 is automatically controlled to be smaller or larger depending on the magnitude of the pull-out load.

The variation of the pressing load on the mold nozzle 5 is determined by the control pressure of the mold nozzle pressing load controller B.
Is measured by the load cell B5, and is input to the control computer E as the pressing load actual measurement value signal. The injection pressure instruction value signal based on this is output to the indicating controller D1 in the molten silicon injection pressure control unit D. ,
By controlling the pressure regulating unit D2 by the electromagnetic valve or the like, the injection pressure by the inert gas or the like in the injection pipe 3 is controlled. Therefore, the injection pressure is adjusted according to the magnitude of the pressing load. The pressure is increased and reduced, and molten silicon S
An appropriate injection pressure at which i does not leak will be maintained.

Further, the injection pressure in the injection tube 3 is:
The pressure is detected by the pressure sensor D3, and this is detected as an injection pressure actual measurement value signal via the indicating controller D1 by the control computer E.
The injection pressure instruction value signal transmitted from the control computer E is fed back to the load power source B2 in the mold nozzle pressing load control section B. As a result, the pressing load corresponding to the injection pressure is automatically adjusted.

Therefore, when actually operating the above-described apparatus, first, the pull-out load is first set to, for example, the first zone (0 to 10 kgf), the second zone (10 to 20 kgf),
The first band (8 kgf), the second band (7 kgf), and the third band (7 kgf) of the pressing load corresponding to the third band (20 to 30 kgf) are preliminarily divided into predetermined bands as shown in FIG. 6 kgf) ‥‥‥, and the first zone of the injection pressure (60 gf /
cm ² ), the second band (50 gf / cm ² ), and the third band (40 gf / cm ² ).

With the above arrangement, the pull-out load actually changes as L with respect to the pull-out distance as shown in FIG. And the pull-out load L
Increases from the first band to the second and third bands (10
kgf → 20 kgf → 30 kgf), the pressing load is changed to the first zone, the second zone and the third zone (8 kg).
f → 7 kgf → 6 kgf), whereby the solidified silicon sheet MSi and the mold nozzle 5
Is reduced, and the pull-out load is reduced, so that undesired pull-out force is not applied to the solidified silicon sheet MSi.

Further, the above pressing load is reduced,
1st band, 2nd, 3rd band (8kgf → 7kgf → 6k
gf), the molten silicon easily leaks from the mold nozzle 5, but at this time, the injection pressure of the molten silicon Si is increased in the first zone, the second zone, and the third zone due to the decrease in the pressing load. Band (60 gf / cm ² → 50 gf / cm ² → 4
Since the pressure is reduced to 0 gf / cm ² ), the above-mentioned leakage can be prevented. Of course, when the withdrawal load is reduced as in the third zone, the second zone, and the first zone, the above-described operation is reversed, and an automatic transition to the most desirable state is always performed. In this manner, as shown in FIG. 3, the pressing load W and the injection pressure P are automatically adjusted in accordance with the pull-out load L.

Next, in claim 2, a predetermined program is further set in the control computer E,
Automatic operation according to the above program can be performed by a predetermined pressing load and a predetermined drawing speed corresponding to the drawing distance of the drawing jig 7.

That is, when the withdrawal distance actual value signal from the pulse counter C4 in the withdrawal force control section C is input to the control computer E, the withdrawal speed is calculated based on the program set therein. Then, a withdrawal speed instruction value signal is output to the motor controller C2, whereby the rotation speed of the motor C1 is controlled to obtain a predetermined withdrawal speed, and at the same time, a pressing load instruction determined in accordance with the withdrawal distance. The load power source B2 of the mold nozzle pressing load control unit B is controlled by the signal, and the predetermined pressing load is automatically controlled throughout the drawing process.

[0037]

According to the present invention, the pressing load on the mold nozzle is automatically adjusted according to the variation of the pull-out load. This eliminates the problem that a certain polycrystalline silicon sheet is pulled out with excessive force and is damaged or broken.

Further, between the above-mentioned pressing load and the injection pressure of the molten silicon, an automatic adjustment function corresponding to each variation can be provided, so that the pressing load is too small or the injection pressure is too large. By doing so, it is possible to correct the conventional difficulty that the molten silicon leaks from the mold nozzle. Also, as compared with the conventional device that requires many trials to find the pull-out force that is appropriate for the pressing load as before,
It will be a big place that contributes to productivity improvement.

According to the second aspect, not only the effect according to the first aspect but also the drawing distance over the entire drawing process from the start to the completion of the drawing of the drawing jig based on the program by the control computer. Therefore, the most ideal production of polycrystalline silicon is always performed uniformly, and the yield of products can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an overall configuration of a polycrystalline silicon manufacturing apparatus according to the present invention, which is partially longitudinally illustrating an embodiment thereof.

FIG. 2 is a table showing respective fluctuation values of a drawing load, a pressing load, and an injection pressure with respect to a drawing distance of a drawing jig when the manufacturing apparatus is operated.

FIG. 3 is a vertical sectional front view showing a conventional apparatus for manufacturing a polycrystalline silicon sheet by a cast ribbon method.

FIG. 4 is an enlarged vertical sectional side view of the mold nozzle in FIG. 3;

FIG. 5 is a vertical sectional front view showing a conventional apparatus for manufacturing a polycrystalline silicon sheet by a ribbon method.

[Explanation of symbols]

 Reference Signs List 1a Inert atmosphere 3 Injection pipe 5 Mold nozzle 5b Lower nozzle 5c Upper and lower nozzle 5e Extraction end 6 Casting path 7 Drawer jig 7a Grip end A Main body A1 Unloader shaft B Mold nozzle pressing load control unit B2 Load power source B5 Load cell C Pull-out force controller C1 Motor C2 Motor controller C3 Load cell C4 Pulse counter D Molten silicon injection pressure controller D2 Pressure regulator D3 Pressure sensor L Pull-out load MSi Solidified silicon sheet P Injection pressure W Pressing load

────────────────────────────────────────────────── ─── Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C01B 33/02-33/039 C30B 15/06-15/08 C30B 29/06 JICST file (JOIS)

Claims (2)

(57) [Claims] In an inert atmosphere, molten silicon in an injection tube is pressurized with an inert gas, and is continuously delivered into a heated mold nozzle to mold the molten silicon into a mold. In the casting path of the nozzle, it flows into the gripping end of the drawer jig which is in contact with the drawout end, and the molten silicon in the gripping end near the drawout end of the mold nozzle solidifies from the gripping end. At that point, while applying pressure to the molten silicon in the injection tube,
By continuously pulling out the drawer jig, the solidified silicon sheet solidified in the mold nozzle is
An apparatus body for performing the cast ribbon method which is continuously drawn from the drawing end port, and a mold nozzle for pressing an upper nozzle and a lower nozzle provided for forming a casting path of the mold nozzle. A pressing load control unit, a pull-out force control unit attached to an unloader shaft connected to the draw-out jig, a molten silicon injection pressure control unit for pressurizing molten silicon in the injection pipe, and a control computer. A load cell provided in the pull-out force control unit inputs a measured pull-out load actual measurement value signal to the control computer, and the press-down load instruction value signal output thereby causes the mold nozzle pressing load to be determined. The holding power of the control unit is controlled freely with respect to the load power source. An actual measured value of the pressing load is input to the control computer by a load cell provided in the load control unit, and the injection pressure instruction value signal output from the control computer is used to control the molten silicon injection pressure control unit. The pressure unit is made controllable, and further, an injection pressure actual measurement value signal measured by a pressure sensor provided in the molten silicon injection pressure control unit is input to the control computer, and a pressing load output thereby is output. An apparatus for producing a polycrystalline silicon sheet by a cast ribbon method, wherein a pressing power of a load power source of the mold nozzle pressing load control section can be controlled by an instruction value signal. 2. The molten silicon in an injection pipe is pressurized with an inert gas in an inert atmosphere, and is continuously delivered into a heated mold nozzle to mold the molten silicon into a mold. In the casting path of the nozzle, it flows into the gripping end of the drawer jig which is in contact with the drawout end, and the molten silicon in the gripping end near the drawout end of the mold nozzle solidifies from the gripping end. At that point, while applying pressure to the molten silicon in the injection tube,
By continuously pulling out the drawer jig, the solidified silicon sheet solidified in the mold nozzle is
An apparatus body for performing the cast ribbon method which is continuously drawn from the drawing end port, and a mold nozzle for pressing an upper nozzle and a lower nozzle provided for forming a casting path of the mold nozzle. A pressing load control unit, a pull-out force control unit attached to an unloader shaft connected to the draw-out jig, a molten silicon injection pressure control unit for pressurizing molten silicon in the injection pipe, and a control computer. A load cell provided in the pull-out force control unit inputs a measured pull-out load actual measurement value signal to the control computer, and the press-down load instruction value signal output thereby causes the mold nozzle pressing load to be determined. The holding power of the control unit is controlled freely with respect to the load power source. An actual measured value of the pressing load is input to the control computer by a load cell provided in the load control unit, and the injection pressure instruction value signal output from the control computer is used to control the molten silicon injection pressure control unit. The pressure unit is made controllable, and further, an injection pressure actual measurement value signal measured by a pressure sensor provided in the molten silicon injection pressure control unit is input to the control computer, and a pressing load output thereby is output. According to the instruction value signal, the pressing force of the load power source of the mold nozzle pressing load control unit can be controlled, and the pull-out distance measured by a pulse counter attached to the unloader shaft of the pull-out force control unit. An actual measurement value signal is input to the control computer, and a pre-programmed pull-out corresponding to the pull-out distance is performed. The speed instruction value signal and the pressing load instruction value signal are input to the motor controller of the motor for the unloader shaft of the pull-out force control unit and the load power source of the mold nozzle pressing load control unit, respectively. An apparatus for producing a polycrystalline silicon sheet by a cast ribbon method.