JP2533686B2 - Semiconductor single crystal manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a semiconductor single crystal production apparatus for producing a homogeneous semiconductor single crystal from a raw material melt in a crucible.

(Prior Art) A CZ (Czochralski pulling) method for growing a columnar crystal from a raw material melt in a crucible is widely used for growing a semiconductor single crystal.

Usually, when growing a semiconductor single crystal, in order to maintain high quality of the grown single crystal, a crucible is installed in a chamber that has been evacuated to a predetermined vacuum degree, and a crystal is produced from the raw material melt in this crucible. The method of raising while raising is adopted.

For example, as shown in FIGS. 4 to 5, the semiconductor single crystal growth apparatus is composed of a chamber 1 and a pulling cylinder 2 connected to the chamber 1, and a heater H and a crucible R are installed in the chamber 1. The seed crystal is immersed in the crucible and pulled up to grow a single crystal.

By the way, the grown single crystal is pulled up onto the pulling cylinder 2, and when the single crystal after pulling out is taken out from the chamber, a door (not shown) on the upper side of the pulling cylinder 2 is opened. At this time, in order to prevent cold outside air from reaching the raw material melt in the chamber, in this device, a gate valve 4 is provided between the pulling cylinder 2 and the chamber 1 to hold the pulling single crystal in the pulling cylinder 2. In this state, the gate valve 4 is closed to separate the vapor phase of the pulling cylinder 2 from the vapor phase of the chamber 1, and a door (not shown) above the pulling cylinder 2 is opened to take out the single crystal. It is taken.

As shown in FIGS. 5 (a) to 5 (c), the structure of this gate valve is such that the gate valve 4 is moved by a support rod 8 which is interlocked with a rotating shaft 7, and an O-ring 6 is provided on a flange 5. The vapor phase of the pull-up cylinder 2 and the vapor phase of the chamber 1 can be separated from each other, or the vapor phase of the two can be made to communicate with each other by removing the vapor phase from the flange 5.

In such a device, high-temperature gas containing silicon oxide (SiO) reaches the chamber inner wall and the pulling cylinder,
There was a problem that this was cooled and condensed and adhered.
When such deposits fall, dislocations often occur in the grown single crystal, which often causes quality deterioration.

In order to solve this problem, an inert gas such as argon (Ar) is introduced into the chamber from below to prevent the high temperature gas containing silicon oxide (SiO) from reaching the inner wall of the chamber and the pulling cylinder. Proposed.

(Problems to be solved by the invention) However, in this structure, since the gas inlet is provided below the chamber, it is not possible to forcibly form a downward flow, and a high temperature gas containing SiO It reaches the valve where it is cooled, condensed and deposited.

For this reason, when the gate valve is moved, the deposit may drop and mix into the raw material melt, which has been a cause of preventing dislocation-free growth of the grown single crystal.

Further, the O-ring for enhancing the airtightness when the gate valve is closed is apt to deteriorate due to the heat in the chamber, which causes the shortening of the life of the apparatus.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a semiconductor single crystal manufacturing apparatus capable of obtaining a highly reliable semiconductor single crystal with few crystal defects such as crystal dislocations.

[Structure of Invention]

(Means for Solving the Problem) Therefore, in the present invention, the gate valve is provided with the inert gas introducing means so that the inert gas is introduced into the chamber from the gate valve.

That is, in the present invention, a chamber provided with a crucible for filling a raw material, a heater for melting the raw material in the crucible to form a raw material melt, and the crucible openably and closably connected to the chamber via a gate valve. A pulling part for dipping a single crystal by immersing a seed crystal in the molten raw material therein, a shield plate arranged on the raw material melt side at a predetermined distance from the gate valve to shield radiation, and the gate valve And an inert gas introducing means configured to flow an inert gas along the inner wall of the chamber, wherein the inert gas introducing means includes a substantially central portion of the gate valve and the shielding plate. When the inert gas flow is formed between the gate valve and the shielding plate along the inner wall of the chamber, the inert gas supply port is provided at a position penetrating the central part of Moni, and forming an inert gas stream downwardly from the central portion of the shielding plate.

Desirably, the introduction of the inert gas is controlled in association with the opening and closing of the gate valve.

(Operation) That is, the gate valve is provided with an inert gas introducing means, the inert gas is introduced into the chamber from the central portion of the gate valve, and the shield plate is provided on the melt side of the raw material, and the gap between the shield plate and The inert gas is satisfactorily guided therethrough to the inner wall of the chamber so that a downward flow is formed along the inner wall of the chamber. On the other hand, the inert gas supplied through the central part of the shielding plate also forms a descending flow that descends directly from the upper part of the chamber, effectively preventing high temperature gas containing silicon oxide from reaching the chamber inner wall and the pulling cylinder. To do.

Therefore, according to the above configuration, even if the high temperature gas containing silicon oxide (SiO) reaches the inner wall of the chamber and the pull-up cylinder by this gas flow, it does not adhere and is forcibly returned to the lower part in a gaseous state. Therefore, it is possible to obtain good crystals with few crystal defects without mixing foreign matter in the raw material melt.

In addition, due to the flow of such an inert gas, it is possible to prevent the high temperature gas from staying in the upper part of the chamber and to prevent the radiant heat from being shielded by the shielding plate, so that the gate valve can be prevented from reaching a high temperature. The deterioration of the O-ring is prevented.

If the introduction of the inert gas is controlled in conjunction with the opening and closing of the gate valve, it becomes possible to grow a high-quality single crystal with good workability.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Example 1 A single crystal growing apparatus of a first example of the present invention has a main part of a single crystal manufacturing apparatus 11 and a pulling tube provided above the single crystal manufacturing apparatus main body 11 as shown in FIG. 1 and FIG. Argon gas introducing means 19 is installed in a gate valve 14 provided between the gate valve 12 and the gate valve 14.

The argon gas introducing means 19 passes through the inside of the gate valve from the center of the rotating shaft 18 for opening and closing the gate valve, and the radiation shielding plate 20 and the gate valve installed at a predetermined interval on the chamber 11 side of the gate valve. Argon gas is ejected from an opening O1 located between the opening O1 and the opening 14 and the radiation shielding plate 20 and an opening O2 located at the center of the opening.

This argon gas introducing means 19 is a spirally formed flow that enters from the outer peripheral side of the circular gate valve 14 through the support shaft 18 from the rotating shaft 17 as shown in the gas flow path inside the gate valve in FIG. Argon gas is injected through the opening O1O2 in the center through the passage.

The argon gas introducing means 19 is switched between on and off in synchronization with the opening and closing of the gate valve 14, and the gas is injected only when the gate valve is closed.

Other parts are configured similarly to the conventional single crystal growth apparatus shown in FIGS. 4 and 5. Crucible,
The pulling device and the like are omitted. Reference numeral 15 is a flange and 16 is an O-ring.

Next, a method for growing a silicon single crystal using the single crystal manufacturing apparatus of FIG. 1 will be described.

First, the chamber 11 and the pull-up cylinder 12 are evacuated while the gate valve 14 is open to 10 ⁻² to ⁻³ Torr.

Then, the heater for heating the crucible (not shown) in the chamber 11 is turned on to obtain the raw material melt.

Then, a seed crystal is immersed in the raw material melt, and a single crystal is grown by pulling it at a predetermined speed by a pulling unit (not shown).

After completion of the growth, the grown crystal is raised in the pulling cylinder, the gate valve 14 is first closed in the same manner as when mounting the seed crystal, and argon gas is allowed to flow into the chamber 11 from the argon gas introducing means 19, while the pulling cylinder The vacuum is released, the upper door (not shown) is opened, and the grown crystal is taken out.

According to this apparatus, the high temperature gas containing silicon oxide (SiO) reaches the inner wall of the chamber and the pulling tube by the flow of the gas which is made to flow into the chamber 11 from the argon gas introducing means 19 provided in the gate valve 14. Even
Since it is forcibly returned to the lower part in a gaseous state without adhering, no foreign matter is mixed in the raw material melt,
A good crystal with few crystal defects can be obtained.

Further, by the inflow of this gas, the gate valve can be cooled in a route from the outer peripheral side of the circular gate valve 14 through the spirally formed flow path to the opening O1O2 in the central portion. Since the heat from the crucible is shielded by the presence of the radiation shielding plate 20, it is possible to prevent the gate valve 14 from reaching a high temperature and prevent the O-ring 16 from being deteriorated.

In this way, it becomes possible to grow a highly reliable single crystal for a long period of time.

In the above embodiment, the argon gas introducing means is operated in conjunction with the opening / closing of the gate valve.
The argon gas introducing means may be manually operated.

Further, if argon gas is caused to flow inside the gate valve and a pipe for water cooling is provided, the cooling effect can be further enhanced and the life of the O-ring 16 can be further extended.

Further, the present invention is not limited to the above-described embodiment,
It is also applicable to various application examples, for example, growth of single crystals other than silicon.

Second Embodiment Next, as a second embodiment of the present invention, as shown in FIG. 3, an argon gas inlet 30 is provided outside the chamber,
You may make it connect with a gate valve using the flexible tube 29.

In the description of this embodiment, the same components as those of the first embodiment of the present invention will be designated by the same reference numerals, and duplicated description will be omitted.

〔The invention's effect〕

As described above, according to the present invention, since the inert gas is allowed to flow from the gate valve into the chamber, a good crystal with few crystal defects can be obtained and the life of the device is increased. be able to.

[Brief description of drawings]

FIG. 1 is a principal part view of an apparatus for producing a single crystal showing a first embodiment of the present invention, FIG. 2 is a view showing an upper surface of a gate valve of the apparatus, and FIG. 3 is a second embodiment of the present invention. FIG. 4 is a diagram showing a conventional single crystal growing apparatus, and FIG. 4 and FIG. 1 ... Chamber, 2 ... Lifting cylinder H ... Heater, R ... Crucible, 3 ... Gate, 4 ... Gate valve 5 ... Flange, 6 ... O-ring 7 ... Rotating shaft, 8 ... Support Rod 11 …… Chamber, 12 …… Pulling cylinder 13 …… Gate, 14 …… Gate valve 15 …… Flange, 16 …… O-ring 17 …… Rotating shaft, 18 …… Support rod 19 …… Argon gas introduction means 20 ...... Radiation shield 29 ...... Flexible tube 30 ...... Argon gas inlet.

Claims (2)

(57) [Claims] 1. A chamber provided with a crucible for filling a raw material, a heater for melting the raw material in the crucible to form a raw material melt, and a chamber which is openably and closably connected to the chamber via a gate valve. A pulling part for dipping a single crystal by immersing a seed crystal in the molten raw material, a shield plate arranged on the raw material melt side at a predetermined distance from the gate valve, and a shielding plate for shielding radiation; And an inert gas introducing means configured to flow an inert gas along the inner wall of the chamber, wherein the inert gas introducing means includes substantially the central portion of the gate valve and the shielding plate. An inert gas supply port is provided at a position penetrating the central portion, and an inert gas flow is formed along the inner wall of the chamber from between the gate valve and the shielding plate. Semiconductor single crystal manufacturing apparatus characterized by forming an inert gas stream downwardly from the central portion of the shield plate. 2. The inert gas introducing means switches the introduction of the inert gas in conjunction with opening and closing of the gate valve, and introduces the inert gas only when the gate valve is closed. The semiconductor single crystal manufacturing apparatus according to claim 1, wherein