JPS58208194A - Method for holding seed crystal for growing single crystal - Google Patents

Abstract

PURPOSE:To hold stably a single crystal with the growth of a large sized crystal, by forming a seed shaft for rotating and moving a single crystal upward to a convergent taper bisected at the forward end and fitting and mounting a cylindrical seed crystal having a convergent taper to said end. CONSTITUTION:The forward end part of a seed shaft 7 is formed to a bisected jig having a convergent taper internally and a cylindrical seed crystal 6 having a convergent taper is fitted and mounted in said forward end part and is fastened by means of an Mo wire or the like 8 in a seed crystal producing device which grows a silicon single crystal by heating and melting single crystal silicon of high purity with a graphite heating element 2 to form a melt 5 in a crucible 1 consisting of two layers; a quartz crucible 3 and a graphite crucible 4, and immersing the seed crystal 6 mounted to the forward end of the shaft 7 in said melt and pulling the single crystal while rotating the shaft 7 in the direction opposite to the crucible 1. There is no possibility of slipping down or failure in the seed crystal 6 in the stage of growing a large-sized crystal.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a method of growing ayu crystals, particularly to a method of growing a seed crystal within the seed axis.

lb) Technology background Semiconductor integrated circuits are made of silicon (Sl), gallium arsenide (G
aA, s) are formed on any single crystal substrate, but these single crystals are produced using the pulling method (also known as the Czochralski method, abbreviated as the C2 method) or the floating Teijyoku ML method (also known as the floating zone method). It is made by the FZ method (abbreviated as FZ method).

Here, the CZ method is characterized by its ability to increase the size and diameter, and the FZ method is characterized by the fact that it is easy to obtain high-purity products, but currently single crystals obtained by the CZ method are not used for applications with large tβ. There are n.

FIG. 1 shows a cross-sectional view of the pulling mechanism of a resistance heating type C2 furnace.The seed crystal holding method of the Hayabusa crystal production apparatus according to the present invention will be explained below by taking the pulling of a solicon single crystal as an example.

The C2 furnace shown in FIG. 1 has a graphite heating element 2 outside the crucible 1, and the crucible 1 is heated by this. Here, the crucible 1 is made up of a combination of a quartz crucible 3 on the inside and a black button crucible 4 on the outside.High purity polycrystalline silicon is put in the former, and the graphite heating element 2 is made into the crucible 1. By heating, the polycrystalline silicon is melted to form a melt 5. Here, a reduced pressure atmosphere of argon (Ar) was maintained in the furnace to prevent oxidation, and the temperature of the melt was kept at 4 degrees Celsius using a Nobu Seko pyrometer and held in a canopy at a temperature below ±02 degrees Celsius. There are n.

Now, to grow a single crystal 1'', the seed crystal 6 is set at the source, and the seed crystal 6 is gradually lowered to the liquid 5, but the temperature of the melt 5 at this time is 41 crystals. The temperature is set at such a temperature that the tip of the 6F is maintained at a temperature that maintains equilibrium while dissolving the WA in a bottle, and after reaching equilibrium, the temperature is raised at 3 to 5 h+1:] 6F81 and the crystal is thinned at 4 degrees. Dislocations in the seed crystal are expelled to the outer periphery, and the generation of dislocations is suppressed to eliminate dislocations.

Next, the pulling stray suction of the seed shaft 7 is lowered, and the temperature is also constantly lowered to increase the diameter K to the desired diameter and to grow early bound crystals in the longitudinal direction.

Incidentally, in order to uniformly stir the melt 5 and keep the temperature uniform during the growth of a fine product, the seed shaft 7 holding the seed crystal 6 and the crucible 1 are rotated in opposite directions. In the CZ furnace that takes structure metal, Saki is growing from the demand of Omagari and diameter enlargement.
Normally, viscous crystals have a diameter of 4 inches, and 5-inch diameters are now being produced.

Now, as explained above, single crystal growth by the CZ method is
This is done by rotating and pulling up the sheet @ 7 on which the crystal 6 is fixed, and the salt peak of the Si content crystal, which has a diameter of 5 inches and a length of 80 [α], reaches 20 [~]. The fixing of the seed crystal 6 to the assembly seed shaft 7 must be done with sufficient strength, and until now, recasting due to slipping or breakage has easily occurred.

(c) Conventional techniques and problems In order to grow a small single crystal with a diameter of 2 to 3 inches, there is a conventional shape identification method shown in Fig. 2.
ing. /'A and existing B crystal 6 into a prismatic fjJAll
At the same time, the tip of a cylindrical seed shaft 7 made of molyphdenum (MO), stainless steel, etc. was cut in such a way that the crystals were covered, and the two were made to match and then fixed using MO class 8. It's tied up.

Silence/P Riko's method of erasure is that one crystal is 2-3 [
4], but it is unsuitable for large crystals with Mt as high as 20 (immediately), as there is a risk of smearing. Therefore, conventionally, as shown in FIG. 3, the tip of the seed crystal 6 and the seed crystal 7 were used as key parts to prevent the dropout. However, in this method, the key part 9 of the sand crystal 6
Due to the load applied to it, cracks were likely to occur in some parts of the ridgeline crystal 6 and damage was likely to occur.

fdJ OBJECTS OF THE INVENTION It is an object of the present invention to provide a method for maintaining the stock status of a seed axis that can sufficiently withstand the growth of large crystals in a single crystal growth method.

tel Structure of the Invention The purpose of the present invention is to fix a seed crystal by forming a jig divided into two parts, the tip of which has an internal taper. By employing a nearly crystalline holding structure characterized by the use of cylindrical seed crystals arranged one after the other, it is possible to produce a crystal.

(fJ Invention Example M4
The 5th section is a diagram of the seed crystal beads attached to the crown, and the 6th section is a perspective view showing the holding structure provided at the tip of the sheet shaft.

Uninventively, as shown in FIG. 5, the seed crystal 6 has a cross-sectional shape in the same direction as the moxibustion direction, or has a smaller cross-sectional shape in the opposite direction. There is a taper part 10 going south, and the upper part of the V holding capital is cut 7jfJ so that it becomes a large concentric circular discrepancy, and the upper part 1 of the cylindrical part 11 is also 0.
2 is shaved off.

tP:,:Eni Seed Crystal 6 Upper Cylindrical Part 11σ Diameter Reduction Approximately 10
(m+s) and has a length of about 10 [p, r;], and the lower cylindrical part has a diameter of about 8 [1z] and a length of about 90 [dragon].

Next, as shown in Fig. 6, the tip of the seed @7 is divided into two parts by inserting a slit 13 in the center of the seed shaft, and the Sugitsugi seed crystal shown in Fig. 5 is placed in the inside t1. Nikiri 61
” It is machined and grooved. As for the thickness of the seed shaft 7, a harpoon with a diameter of about 20 [11I doors] is used. Here, divide the tip of the seed shaft 70 into two and use p-1tQ.
The reason why 13 is provided is to prevent the seed crystal 6 from being damaged and the IVIO that constitutes the seed axis 1.

Its role is to prevent loss of food crystals due to the difference in the number of expansion threads between the stainless steel metal and the seed crystal.

The reason why the part 12 of the upper cylinder 11 of the cylindrical crystal 6 is removed is due to the reed cutting 7 of the crystal 6 while manipulating the crystal's pull.
It comes out to prevent tripping. In addition, as shown in the tip part d*41i71c of the seed shaft divided into two, it is secured by MO kneading 8 or the like. When such a fixed structure is adopted, the RI strand crystal 6 is held by the upper cylinder 11 having a taper 10, so it is stably held even in the pigeonhole where large ff1M crystals are grown. There is no risk of damage due to double cracking and there is no chance of damage.

(g) Effects of the Invention By implementing the present invention, even when pulling a large Si single crystal with a length of IL and 5 inches, the seed crystal can be stably fixed to the seed shaft and can be broken without falling. We were able to eliminate long-term failures.

[Brief explanation of drawings]

Figure 1: WT view of CZ furnace pulling machine ellipse, interior of cram school 2 and Figure 3 #-i: explanatory diagram of conventional 1f-IikS crystal-retaining violet construction,
The 4th surface to the 6th factor are seed M crystal holding structures according to the present invention;
Figure LLT curve diagram, Figure 5 is a perspective view of the Muku crystal, and Figure 6 is a perspective view of the tip of the seed shaft.

Claims (1)

[Claims] # in the crucible melting in the crucible? [In a single crystal manufacturing apparatus in which a single crystal is epitaxially grown using the m crystal as a core by immersing a seed crystal provided at the tip of a heseed shaft and rotating and raising the seed shaft while maintaining equilibrium, the ridge δ,
The tip of the seed shaft for fixing the 5 crystals is formed from a two-part stem with a tapered inner part, and a cylindrical spear knot 77 with a taper of 9 is fitted and attached to the tip. A method for holding seed crystals for blood crystal growth, characterized in that the method is used as a seed crystal for blood crystal growth.