JPS62270488A - Production apparatus for beltlike silicon crystal - Google Patents

Abstract

PURPOSE:To obtain a beltlike crystal having an uniform thickness, by forming an opening part and bottom of a crucible into specific shapes in lifting silicon melt in a bottomed boxlike crucible with a thin sheetlike crystal seed and a pair of filamentous supports. CONSTITUTION:The shape of a crucible 11 containing silicon melt is in the form of a bottomed box and the end part of an opening part (11a) in the width direction of a beltlike silicon crystal 15 to be grown is formed into a narrow part. Holes (12a) and (12b) for inserting a pair of filamentous supports are provided in the bottom part (11b) corresponding to the narrow part. The bottom part (11b) is formed into a convex part from the center toward the end parts relative to the crystal pulling up direction. The silicon melt 16 is contained in the crucible 11 and filamentous supports (13a) and (13b) are then passed through the holes (12a) and (12b) to lift and crystallize the silicon melt 16 with the filamentous supports (13a) and (13b) and a thin sheetlike crystal seed 14. Thereby the aimed beltlike silicon crystal 15 is produced.

Description

[Detailed description of the invention] 3. Detailed description of the invention [Purpose of the invention] (Industrial application field) The present invention relates to an apparatus for manufacturing band-shaped silicon crystals.

(Prior Art) In general, band-shaped silicon crystals have a thin plate-like shape, so unlike silicon crystals in the shape of an in-bore shape obtained by the Czochralski method, etc., a semiconductor device can be manufactured using the obtained shape. It can be used as a PC board. In other words, it is possible to realize an inexpensive semiconductor device substrate with less material loss, which is required when creating a thin plate-shaped semiconductor device substrate by slicing an in-bod-shaped silicon crystal grown by the Czochralski method or the like. becomes possible.

By the way, FIGS. 6, 7(a) and 7(b) show a conventional example of a manufacturing apparatus for a band-shaped silicon crystal (described in Japanese Patent Application Laid-Open No. 125297/1983) for growing the above-mentioned band-shaped silicon crystal. As shown in the figure, the carbon crucible 1 of this device is shaped like a box with a bottom, the opening is rectangular, and the thickness of the bottom is uniform. Through-holes 2a and 2b for inserting thread-like supports are bored.

In order to produce a band-shaped silicon crystal using such a crucible 1, a silicon raw material contained in the crucible 1 is heated and melted from the outside to obtain a silicon melt 6. Then, a pair of thread-like supports 3a, 3b are inserted into the crucible 1 so as to maintain a certain distance perpendicularly to the silicon melt 6 surface from the pair of thread-like support insertion holes 2a, 2b formed in the bottom of the crucible 1.
is inserted between the pair of filamentous supports 3a and 3b,
A thin plate crystal seed 4 is arranged so as to be in contact with the silicon melt 6. At this time, the pair of filamentous supports 3a, 3b and the thin plate crystal seed 4 are made of a substance that has good wettability with the silicon melt 6, and when the thin plate crystal seed 4 is pulled up, the silicon melt 6 in the contact area It is lifted above the melt surface, cools, and crystallizes. At this time, the thin plate-like crystal seeds 4 and the pair of thread-like supports 3a
, 3b are both attached. Therefore, the thin plate crystal W14
By pulling up the pair of filamentous supports 3a, 3b
is also pulled up, and the thin plate-like crystal seeds 4 and the pair of thread-like supports 3a
.

3b as a support, the silicon melt 6 is lifted from the melt surface in the direction F and crystallized, so that a band-shaped silicon crystal 5 is grown.

(Problems to be Solved by the Invention) When the band-shaped silicon crystal 5 is manufactured using the conventional apparatus as described above, the crystal width is defined by the thread-like supports 3a and 3b at both ends of the crystal, but the crystal width is Since there is no standard for the crystal thickness, it is difficult to make the crystal thickness uniform.

That is, in the above case, the silicon melt 6 surface before seeding is almost flat and is in the state shown in FIG. 7(a). When the crystal seed 4 is pulled up, the silicon melt 6 at the contacting portion is lifted above the melt surface, and the cooled portion crystallizes, as shown in FIG. 4(b). However, since heat dissipation is larger at the crystal edges than at the crystal center, the temperature distribution at the solid-liquid interface becomes lower at the crystal edges, and a solid-liquid interface 7 is formed as shown in FIG. 7(b), and a meniscus 8 is higher at the center of the crystal than at the ends of the crystal, and is convex in the crystal pulling direction. Therefore, the end portions of the crystal are thicker than the central portion of the crystal, and a band-shaped silicon crystal 5 having a bell-shaped cross section as shown in FIG. 3(b) is grown.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an apparatus for manufacturing band-shaped silicon crystals that can easily obtain band-shaped silicon crystals with uniform thickness.

[Structure of the Invention (Means for Solving Problems) This invention provides a crucible containing a silicon melt, and a crucible in which holes are formed at approximately equal intervals to the width of the band-shaped silicon crystal to be grown at the bottom of the crucible. a pair of thread-like supports inserted through the holes, and a pair of thread-like supports arranged perpendicularly to the silicon melt surface through which the silicon melt is inserted into the through holes,
By bringing a thin plate crystal seed into contact with the pair of R- filamentous supports and the silicon melt, and pulling up the crystal seed, the silicon melt is stretched between the pair of filamentous supports by surface tension. is continuously crystallized to obtain band-shaped silicon crystals. In the production of band-shaped silicon crystals, the shape of the crucible is such that the opening is narrow at the end in the width direction of the band-shaped silicon crystal to be grown, and the pair of through-holes for inserting the thread-shaped supports are formed in correspondence with this narrow portion. This is an apparatus for producing a band-shaped silicon crystal, in which the bottom part is convex from the center toward the ends in the pulling direction, so that the surface of the silicon melt during crystal growth is flat.

(Function) In this invention, the shape of the crucible containing the silicon melt narrows the widthwise end of the band-shaped silicon crystal to be grown, and raises it above the surface of the silicon melt in that part by capillary action. , the bottom of the crucible is convex in the opposite direction to the pulling direction to flatten the surface of the silicon melt during crystal growth, so that a band-shaped silicon crystal with a uniform thickness can be obtained. be.

(Embodiment) Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. That is, an apparatus for manufacturing a band-shaped silicon crystal according to the present invention includes:
It is constructed as shown in FIGS. 1 and 2 (a) and (b), and 11 is a crucible in which a silicon melt 16 is accommodated.

The shape of this crucible 11 differs from the conventional row described above, in that it is shaped like a box with a bottom, the opening 11a is formed narrowly at the end in the width direction of the band-shaped silicon crystal 15 to be grown, and the eaves 11b extends in the pulling direction. On the other hand, it is formed in a convex shape from the center toward the ends, so that the surface of the silicon melt 16 becomes flat during crystal growth. Furthermore, the bottom portion 11b of the crucible 11
A pair of through holes 12a and 12b for inserting thread-like supports are bored at approximately equal intervals to the width of the band-shaped silicon crystal 15 to be grown. The positions of the through holes 12a and 12b correspond to the narrow widthwise ends of the opening 11a. During use, a pair of filamentous supports 13a and 13b are inserted into the through holes 12a and 12b, and are arranged perpendicularly to the surface of the silicon melt 16 through the silicon melt 16.

Now, in order to produce a band-shaped silicon crystal using the apparatus of the present invention as described above, a silicon raw material is placed in the crucible 11 and heated to melt the silicon raw material. The surface of the silicon melt 16 before being brought into contact is as shown in FIG. 2(a). That is, since the opening 11a of the crucible 11 is narrowed at both ends in the width direction, the sides of the silicon melt 16 at both ends rise higher than the sides of the silicon melt 16 at the center of the crucible 11 due to capillary action.
The liquid surface shape becomes convex in the opposite direction to the pulling direction. , In this state, the through hole 12 bored in the bottom 11b of the crucible 11
A, 12b are passed through filamentous supports 13a, 13b, and the thin plate-shaped crystal seed 14 is brought into contact therewith. When this thin plate-shaped crystal seed 14 is pulled upward, the surface of the silicon melt 16 in the crystal growth region is lifted, but the opening 1 in the crucible 11
By narrowing both ends of 1a, the silicon melt 16 at both ends rises higher than the center, so the surface of the silicon melt 16 at this time becomes flat as shown in FIG. 2(b). Moreover, the solid-liquid interface 17 also becomes flat.

That is, the surface of the silicon melt 16 during crystal growth becomes flat.

In this example, when a band-shaped silicon crystal with a width of 10 cm and a thickness of 400 μm was pulled, it was possible to obtain a band-shaped silicon crystal with a substantially uniform thickness as shown in FIG. 3(a).

(Modification 1) In the above embodiment, the filamentous supports 13a and 13b are placed in the crucible 1.
1 through the narrow part of the frontage 11a. However, when the temperature of the silicon melt 16 is lowered in order to pull the band-shaped silicon crystals at a higher speed, the inner wall of the crucible 11 and the filamentous supports 13a and 13b are close to each other, so that solidification immediately occurs on the inner wall of the crucible 11. It progressed to solidification and crystal growth was interrupted.

Therefore, as shown in FIG.
The narrowed portions at both ends of a are connected to thread-like supports 13a, 13
The band-shaped silicon crystal was pulled from b, that is, from the outside of the crystal to be grown.

In this case, although the surface of the silicon melt 16 during growth did not become flat as in the above example, it was possible to obtain a band-shaped silicon crystal with a fairly uniform thickness.

(Modification 2) As shown in FIGS. 5(a) and 5(b), if the tops of both ends of the crucible 11 are made sharp and the top of the crucible 11 is covered with a heat shield material 18, the result will be more than the case of the above embodiment. It was possible to obtain band-shaped silicon crystals with uniform thickness at a pulling rate of 1.5 to 2.0 times.

[Effects of the Invention] According to the present invention, the shape of the crucible 11 containing the silicon melt 16 is such that the opening 11a is narrow at the end in the width direction of the growing band-shaped silicon crystal, and the bottom 11b is narrow in the pulling direction. On the other hand, since the silicon melt 16 is made convex from the center to the end so that the surface of the silicon melt 16 is flat during crystal growth, it is possible to obtain a band-shaped silicon crystal 15 with a uniform thickness.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) show a crucible of an apparatus for producing band-shaped silicon crystals according to an embodiment of the present invention, in which (a) is a plan view, and (b) is (a>, l-A'). 2(a) and (b) are sectional views cut along the line and viewed in the direction of the arrow; FIGS. 2(a) and 2(b) are sectional views showing the state in which a band-shaped silicon crystal is manufactured using the manufacturing apparatus of the present invention; FIG. a>, (b) are cross-sectional views showing crystal cross sections of band-shaped silicon crystals obtained using the present invention and each conventional device, and FIGS. 4(a) and (b) are related to a modification of the present invention. An apparatus for producing band-shaped silicon crystals is shown, (a
) is a plan view, (b) is a sectional view taken along the line AA' in (a) and seen in the direction of the arrow, and FIGS. FIG. 6 is a perspective view showing a conventional belt-shaped silicon crystal production apparatus, and FIG. 7(a) is a perspective view and an exploded perspective view. (b) is a cross-sectional view showing a state in which a band-shaped silicon crystal is manufactured using a conventional manufacturing apparatus. 11... Crucible, 11a... Opening, 11b...
Bottom part, 12a, 12b...Thread-like support insertion hole, 1
3a, 13b... Thin-like support, 14... Thin crystal seed, 1... Band-shaped silicon crystal, 16... Silicon melt, 17... Solid-liquid interface, 18... Heat shield material . Applicant's representative Patent attorney Takehiko Suzue Figure 2 Figure 3 Figure 6 Figure 7

Claims (1)

[Claims] (1) A crucible containing a silicon melt, a pair of through holes for inserting thread-like supports, which are bored at the bottom of the crucible at approximately equal intervals to the width of the band-shaped silicon crystal to be grown; A pair of filamentous supports are inserted and arranged perpendicularly to the surface of the silicon melt through the silicon melt, and a thin plate crystal seed is brought into contact with the pair of filamentous supports and the silicon melt, and the crystal is In an apparatus for producing a band-shaped silicon crystal, in which a band-shaped silicon crystal is obtained by continuously crystallizing the silicon melt stretched between the pair of filamentous supports by surface tension by pulling up a seed, the crucible is The shape is a box with a bottom, and the opening is narrow at the end in the width direction of the band-shaped silicon crystal to be grown, and the pair of through holes for inserting the thread-shaped supports are located corresponding to this narrow part, and the bottom part is narrow. is convex from the center to the end in the pulling direction,
1. A device for manufacturing a band-shaped silicon crystal, characterized in that the device is configured so that a silicon melt surface is flat during crystal growth.