JPH0311214Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a manufacturing tray used for manufacturing polycrystalline silicon wafers used in solar cells, other photoelectric conversion elements, and the like.

Conventionally, the most common method for producing the above-mentioned polycrystalline silicon wafers is to once cast an ingot of a predetermined shape from a silicon base material and then slice the ingot to obtain the wafer.

As methods that do not involve slicing, a ribbon method and a casting method have already been implemented.

However, with the slicing method mentioned above, not only does the slicing process take a lot of time, but also about 50% of the ingot is lost during slicing.
The product cost is high and mass production is not possible.

In addition, the above-mentioned ribbon method and casting method have the disadvantage that large-sized solar cell materials cannot be obtained, and furthermore, in the casting method, the silicon crystal grains become extremely fine and large crystal grains cannot be obtained, so the wafer The photoelectric conversion efficiency of the solar cell obtained by this method is also extremely poor at 2 to 3%.

Therefore, the applicant has already developed a method for manufacturing polycrystalline silicon wafers that can improve the defects of the above-mentioned methods, by melting a silicon base material and using this melt as a method of manufacturing polycrystalline silicon wafers made of quartz or carbon and in a rotating state. A method in which a thin layer of melt with a desired expanded diameter is layered by dripping onto a production plate, etc. by effectively utilizing centrifugal force, and this is peeled off from the production plate after solidification (hereinafter referred to as the spin method) ) was proposed.

Regarding this spin method, as shown in Figure 1A, this application prepares a single plate body a,
A cross-shaped wafer molding groove b is formed on the upper surface of the dish body a, the bottom surface of which serves as a wafer molding plane c, and a square wafer molding part d is formed on the end side of the groove b. A lid body f is formed by forming four through holes e in the center as shown in FIG.
into the dish body a as shown in FIG. 2,
A manufacturing pan is proposed in which a thin layer of melt is formed by injecting and filling the melt through the through hole e into the wafer molding space g defined by the lid f and the pan main body a.

The above-described spin method using this manufacturing pan has many excellent features, but when using the manufacturing pan, the melt injected and filled from the through-hole e can be Although the flow once flows down into the central portion b' of the groove b, it flows into the wafer forming space g direction due to rotational centrifugal force.
According to the shape, it is difficult for the melt in the central portion b' to flow toward the wafer forming space g, and as a result, the same space g
In some cases, the melt did not flow to the end of the mold, resulting in defects that made it difficult to obtain a product with a satisfactory shape.

The present invention was devised in view of the current situation, and its purpose is to position each wafer molding part formed on the end side of the concave groove of the dish body at a desired deviation position in the above-mentioned manufacturing dish. At the same time, the central injection part into which the melt is injected is configured to communicate with each wafer molding part through a communication neck that does not deviate, thereby preventing the flow of the silicon melt due to rotational centrifugal force. The present invention aims to provide a production pan that can improve the flow rate, make it possible to flow uniformly over the entire area of the wafer molding part, and also make it possible to increase the size of the wafer molding part, thereby producing a large silicon sheet with a desired layer thickness. That's what we're trying to offer.

Below, the present invention will be described in detail based on the illustrated embodiment.A production plate A is composed of a plate main body 1 as shown in FIG. 3A, and a lid body 2 as shown in FIG.
These members are made of quartz SiO ₂ or carbon, which has little reactivity with silicon.

The plate main body 1 has an upper surface 3 formed on the same day.
A concave groove 4 having a substantially eccentric cross shape in plan is formed, the bottom surface of which serves as a wafer molding plane 5, and four wafer molding portions 6, which are rectangular in the illustrated embodiment, are formed on the end side of the groove 4. has been done.

Each of these wafer molding parts 6... communicates with an injection part 7 at the center, and each of these wafer molding parts 6...
At the continuous part of the injection part 7, there is a weir 8 that is approximately perpendicular to the communication direction and protrudes from one side.
are formed, respectively, so that the injection part 7 communicates with each wafer molding part 6 through communication neck parts 7', 7', which are formed narrower than the wafer molding part 6. ing.

As shown in FIG. 4, the lid 2 is removably fitted onto the upper surface 3 of the dish main body 1 with screws 9. A hole 10 is formed corresponding to the injection part 7 of the groove 4 in the dish body 1, and a hole 10 is formed in the bottom surface 1 of the lid body 2.
1 is formed smoothly so as to be in close contact with the upper surface 3 of the dish main body 1.

In order to assemble the plate body 1 and lid body 2 formed in this way to construct the production plate A, first the plate body 1 is placed on a turntable (not shown), as shown in FIG. And a recessed hole 12 provided on the bottom surface...
is fixed by engaging with a connecting bolt (not shown) of the turntable, and then the lid body 2 is stacked on the top surface 3 of the dish main body 1, and these are removably fixed with screws 9. Ru.

Therefore, in the above composition state, a wafer molding space 13 is defined by each wafer molding part 6 at the end of the groove 4 in the dish body 1 and the lower surface 11 of the lid 2, and each wafer molding space 13 is defined by the lower surface 11 of the lid 2. The spaces 13 are configured to communicate with the through holes 10 of the lid body 2 through the injection portion 7 and the communication portions 7', 7', .

Here, in the present invention, each wafer molding part 6 in the groove 4 of the dish body 1 is further arranged along a straight line The center position is shifted to the right or left side in the circumferential direction from Y-Y'.

That is, when the production plate A is rotated in the direction of the arrow B shown in FIG. Formed by shifting clockwise in the circumferential direction, and opposite to arrow B
When rotated in the direction, it is formed so as to be shifted in the circumferential direction to the left. And each of the above weirs 8
If each of the wafer molding parts 6 is provided shifted to the right, it should be formed so as to protrude from the shifted side of the continuous part, as shown in the figure, and contrary to the above, it should be formed to the left. In the case where they are provided offset, they are formed to protrude in the opposite direction from the side opposite to that shown in the figure, and furthermore, the communicating necks 7', 7'...
The silicone solution injected and dropped into the central position of the injection part 7 of the rotating production plate A, which is placed on a predetermined radial line Y-Y' without being substantially deviated, is caused by the rotation. The wafer molding section 6 is aligned in the direction of the arrow in FIG.
This makes it easy for the melt to flow evenly throughout the...

Furthermore, if the tip of each of the weirs 8 is provided with an inclined surface 8a in the direction in which the silicon melt flows in as indicated by the arrow in FIG. It can be done.

In the above configuration, when manufacturing silicon wafers using this, manufacturing plate A shown in FIG.
may be placed on a turntable (not shown) and rotated at a desired speed, while injecting the silicon melt through the through hole 10 of the lid 2. At this time, in the illustrated embodiment, the production plate A is Rotate in the direction of arrow B in Figure 3 A.

If the melt is injected from the through hole 10,
The melt is injected and dropped into the center position of the injection part 7 on the wafer forming plane 5, and the melt is applied to each wafer from each communication neck 7', 7', etc. by the centrifugal force of the rotating production plate A. The wafer molding spaces 13 flow into the wafer molding spaces 13 by increasing the diameter of the wafer forming parts 6..., but at this time, the communication neck parts 7', 7' Since there is a weir 8 protruding in the direction shown in the figure, the melt flows in the direction of the arrow shown in FIG. 5, that is, in the same space 13...
The silicon solution flows from the left to the right, and the silicon solution flows uniformly over the entire area of each wafer forming space 13, forming a thin layer of melt in the wafer forming space 13. Thereafter, by cooling and solidifying this, four silicon wafers can be formed at the same time in the illustrated example.

Note that this manufactured silicon wafer has a communication neck 7' between the wafer molding section 6 and the injection section 7,
By folding using the points 7'..., the product wafers are divided into rectangular product wafers.

The wafer manufactured in this way has its front and back surfaces and outer peripheral surface surrounded by the groove 4 of the dish body 1, the wafer molding plane 5 of the dish body 1, and the lower surface 11 of the lid body 2. These surfaces suppress the unevenness that occurs on the surface when the thin melt layer is cooled and solidified, so that a wafer with a smooth surface is formed.

Further, the remaining portion of the thin melt layer formed in areas other than the wafer molding section 6 is melted again and used.

As explained above, according to the production plate according to the present invention, the plate body 1 has the wafer molding portion 6 formed on the end side of the groove 4 provided on the upper surface, and the through hole 10 in the center.
and a lid body 2 which surrounds the wafer molding space 13 by opening and fitting onto the dish body 1, and the wafer in the concave groove 4 rotates in a desired atmosphere. The melt of the silicon base material is supplied from the through hole 10 to the injection part 7 on the molding plane 5, and a thin layer of the melt is formed by rotational centrifugal force, and this is solidified to form a polycrystalline silicon wafer. In the manufacturing pan that is manufactured, a wafer molding portion 6 of a desired shape is provided on the tray main body 1 or on the end side of the groove 4 thereof, and is offset to the left or right side in the circumferential direction from a predetermined diameter line. , 6... are formed, respectively, and these wafer molding parts 6, 6... are communicated with the injection part 7 through communication neck parts 7', 7'... formed on the desired diameter line. The silicon melt injected into the injection part 7 of the rotated wafer molding plane 5 curves and flows from the communicating neck part 7 into the wafer molding part 6, and the silicon melt is sufficiently diffused. Therefore, by uniformly flowing the melt over the entire wafer forming space 13, a thin layer of the melt having a desired shape and uniform layer thickness is formed, and this is solidified. High quality silicon wafers can be manufactured.

Furthermore, since sufficient diffusion of the silicon melt can be made possible as described above, the dimensions of the wafer molding section 6 can be made considerably larger than those of the current production tray, and large silicon wafers can be processed. can also be easily manufactured.

[Brief explanation of the drawing]

Figures 1A and 2B are plan views of the dish main body and lid of the production dish already proposed by the applicant, Figure 2 is a longitudinal side view of the same production dish, and Figure 3A and 3B are according to the present invention. Each plan view of the dish main body and lid body in the production dish concerned, 4th
The figure is a longitudinal sectional side view of the same manufacturing dish, and FIG. 5 is an explanatory view showing the diameter-expanding flow state of the silicon melt in the same manufacturing dish. A...Production plate, 1...Dish body, 2...Lid, 4...Concave groove, 5...Wafer molding plane, 6...Wafer molding part, 7
...Injection part, 7'...Communication neck part, 10...Wafer molding space.

Claims (1)

[Scope of utility model registration request] A dish body having a concave groove formed on the top surface and whose bottom face is a wafer forming plane, and a through hole formed approximately in the center to fit into the dish body, thereby surrounding a wafer forming space. The melt of the silicon base material is supplied from the through hole to the injection part on the wafer molding plane that rotates in a desired atmosphere, and a thin layer of the melt is formed by rotational centrifugal force. In a manufacturing pan that is used for manufacturing polycrystalline silicon wafers by layering and solidifying the layers, in the tray body, on the end side of the groove, there is a groove on the left or right side in the circumferential direction from a predetermined diameter line. A manufacturing dish comprising forming wafer molding parts having desired shapes that are deviated toward the injection molding part, and communicating these wafer molding parts with the injection part through a communication neck formed on the predetermined diameter line.