KR102775318B1 - A method for charging silicon in a semiconductor single crystal growth device using a hopper device equipped with a hopper filter - Google Patents

Abstract

The present invention relates to a hopper filter for removing impurities or dust generated in a process of loading a solid raw material such as silicon into a hopper device in a process of charging a semiconductor single crystal growth device with the solid raw material, and a method of charging a solid raw material from which impurities or dust have been removed into a semiconductor single crystal growth device through a hopper device using the hopper filter.

Description

{A method for charging silicon in a semiconductor single crystal growth device using a hopper device equipped with a hopper filter}

The present invention relates to a hopper filter for removing impurities or dust generated in a process of loading a solid raw material such as silicon into a hopper device in a process of charging a semiconductor single crystal growth device with the solid raw material, and a method of charging a solid raw material from which impurities or dust have been removed into a semiconductor single crystal growth device through a hopper device using the hopper filter.

As a method for manufacturing single crystal semiconductors, the Czochralski method, which grows and pulls a crystal from a melted silicon or germanium crystal in a crucible, is widely known.

This Czochralski method involves filling a crucible with solid raw materials, usually polycrystalline, and heating them to melt them to create a crystal melt, then bringing a single crystal seed into contact with the crystal melt and slowly pulling it up to grow a single crystal ingot with the desired diameter.

There are three known methods for supplying solid raw materials to the crucible of a single crystal semiconductor growth device, classified by the form of the solid raw materials.

First, a method of supplying an irregularly shaped chip-shaped solid raw material directly from above the center of the crucible, second, a method of supplying a particle-shaped solid raw material directly or obliquely from above the center or obliquely from above the crucible, and third, a method of melting a rod-shaped solid raw material while slowly supplying it downward from above the center of the crucible.

These three methods each use a different type of supply device depending on the type of raw material, and each has its own advantages and disadvantages. However, the first method is most widely used because it is the easiest and cheapest to obtain raw materials and can use recycled raw materials.

The following prior arts are known regarding this first method and its device:

Figure 1 is a cross-sectional view showing a conventional semiconductor single crystal growth device and hopper device disclosed in Japanese Patent Publication No. 2004-244236.

A solid raw material supply device, also known as a hopper device (Hooper, 30), is composed of a vertical cylindrical hopper body (32) in which chip-shaped solid raw materials to be supplied to a crucible are loaded, an upper cover (56) covering the upper opening of the hopper body, a hopper cone (36) blocking the lower opening of the hopper body, and a support rod (76) connected to the upper end of the hopper cone and penetrating the inside of the hopper body to prevent the hopper cone from falling down due to the load of the solid raw material and to appropriately open the hopper cone to control the falling amount and falling speed of the solid raw material.

Here, the hopper body (32), upper cover (56), hopper cone (36) and support rod (76) are usually made of quartz or quartz glass, and the support rod is made of a heat-resistant metal such as quartz, glass or molybdenum.

In addition, the hopper cone (36) has a cone shape with the apex of the cone on the side facing the solid raw material, so that it blocks the lower opening of the hopper body (32) while being pulled upward by the support rod (76), and as the support rod (76) moves downward, the lower opening of the hopper body opens, allowing the solid raw material to be charged into the crucible (20).

The above-mentioned solid raw material supply device, the hopper device (30), can be used when initially charging solid raw materials into an empty crucible (20), but is generally used when additionally charging or recharging.

That is, the productivity of a single crystal ingot is proportional to the volume of the crucible and the amount of melt filled in the crucible. When solid raw materials are first filled and melted in an empty crucible, the volume of the melt is greatly reduced compared to the volume of the solid raw materials supplied due to the gaps between the solid raw materials.

Therefore, by performing additional charging to supplement solid raw materials, the amount of melt is increased and productivity is improved.

However, when the solid raw material loaded inside the hopper body (32) is filled into the crucible, the solid raw material hits the surface of the hopper cone (36), and this impact often causes the hopper cone (36) made of quartz or quartz glass to break.

Pieces of the hopper cone (36) that are broken in this way fall into the crucible together with the solid raw material, and as a result, quartz components are added to the high-purity crystal melt, causing contamination, making it impossible to produce high-quality single crystal ingots and causing problems such as a decrease in yield.

Patent Document 1: Japanese Patent Publication No. 2004-244236 (Published on September 2, 2004) Patent Document 2: Domestic Patent Publication No. 10-2023-0066802 (Publication Date: 2023.05.16) Patent Document 3: Domestic Patent Publication No. 10-2015-0106204 (Publication Date: 2015.09.21) Patent Document 4: Domestic Patent Publication No. 10-2007-0029047 (Publication Date: 2007.03.13)

Accordingly, the present invention has been made to solve the above problems, and the purpose of the present invention is to remove as much glass powder or silicon dust as possible generated in the process of loading polycrystalline silicon into a hopper device before additionally charging solid raw materials into a semiconductor single crystal growth device, and then charge silicon into a crucible of a single crystal growth device, thereby eliminating adverse effects caused by contamination of the silicon melt when additional solid raw materials are added during the single crystal growth process.

In order to achieve the above object, the present invention is a hopper device for charging silicon into a semiconductor single crystal growth device, comprising: a vertical cylindrical hopper body in which silicon to be loaded into a crucible of the semiconductor single crystal growth device is loaded; an upper cover covering an upper opening of the hopper body; a hopper cone mounted to block a lower opening of the hopper body; and a connecting support rod connected to an upper end of the hopper cone and penetrating the inside of the hopper body to prevent the hopper cone from falling down due to the load of the silicon and to appropriately open the hopper cone to control the amount and speed of falling silicon;

A hopper device having a hopper filter is provided, characterized in that a hopper filter having perforations is mounted on the lower opening of the hopper body, and dust and impurities generated when silicon is loaded into the hopper body are discharged through the perforations, and then the hopper cone is mounted on the lower opening of the hopper body.

In addition, in order to achieve the above object, the present invention proposes a method for charging silicon into a semiconductor single crystal growth device by loading silicon into a hopper device, the method comprising: a step of mounting a hopper filter having perforations formed in the lower opening of a vertical cylindrical hopper body; a loading step of discharging dust and impurities generated when silicon to be supplied to a crucible of a semiconductor single crystal growth device is loaded into the hopper body through the perforations of the hopper filter; a filtering step of discharging dust and impurities through the perforations of the hopper filter by introducing gas into the hopper body loaded with the silicon; a step of mounting a hopper cone below the hopper filter to block the lower opening of the hopper body; and a step of charging the silicon loaded in the hopper body into the crucible of the semiconductor single crystal growth device while opening the hopper cone.

As described above, according to the present invention, prior to the process of charging a solid raw material such as silicon or germanium into a semiconductor single crystal growth device, a hopper filter is used as a pretreatment to remove glass powder or dust generated when loading the solid raw material into the hopper device, so that high-purity silicon from which impurities and dust have been removed can be supplied to the crucible of the semiconductor single crystal growth device, thereby preventing contamination of the silicon melt.

This enables the production of high-quality single crystal ingots and improves yield.

Figure 1 is a cross-sectional view showing a conventional semiconductor single crystal growth device and a hopper device.
Figure 2 is a cross-sectional view showing a semiconductor single crystal growth device and a hopper device of the present invention.
FIG. 3 is a cross-sectional view illustrating a state in which a solid raw material is charged into a crucible of a semiconductor single crystal growth device using the hopper device of the present invention.
FIG. 4 is a cross-sectional view of a hopper filter mounted on a hopper device according to an embodiment of the present invention and a mounting state diagram of the hopper filter.
FIG. 5 is a diagram showing a state of use for charging silicon into a semiconductor single crystal growth device using a hopper device equipped with a hopper filter according to an embodiment of the present invention.
FIG. 6 is a flow chart of a method for filling silicon into a semiconductor single crystal growth device using a hopper device equipped with a hopper filter according to an embodiment of the present invention.

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

Prior to this, terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, and should be interpreted as meanings and concepts that conform to the technical idea of the present invention based on the principle that the inventor can appropriately define the concept of the term in order to explain his or her own invention in the best way.

Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

Figure 2 is a cross-sectional view showing a semiconductor single crystal growth device and a hopper device of the present invention. In this embodiment, the semiconductor to be grown as a single crystal is described as silicon, but the present invention can be applied in the same way to crystal growth of other semiconductors such as germanium.

In addition, although the solid raw material supplied in this embodiment is described as amorphous (chip-shaped) polycrystalline silicon, it is of course true that the present invention can be applied even when supplying particle-shaped polycrystalline silicon or regenerated silicon. Furthermore, although this embodiment describes an example in which the solid raw material is additionally charged or recharged while the crystal melt remains in the crucible, it is of course true that the present invention can be applied even when filling the solid raw material into an empty crucible.

As shown in FIG. 2, the hopper device (200) of the present embodiment is mounted on the gate (170) of the growth device to supply polycrystalline silicon (400) in the form of chips to the crucible (120) of the single crystal growth device (100).

The hopper device (200) has a cylindrical hopper body (210) in which polycrystalline silicon raw material (400) is loaded, a conical hopper cone (220) that blocks an opening at the bottom of the hopper body, an upper cover (230) that blocks an opening at the top of the hopper body (210), and a connecting support rod (300) that is connected near the top of the hopper cone (220) and penetrates the inside of the hopper body (210).

The hopper body (210) has a cylindrical structure that loads polycrystalline silicon (400), which is a solid raw material, inside, and a stopper (240) that protrudes continuously or discontinuously is formed on the outer surface of the hopper body (210). When the hopper device (200) of the present embodiment is mounted on the upper part of the single crystal growth device (100), the stopper (310) serves to fix the hopper body (210) at a certain position by allowing the stopper (240) to be caught on the gate (170). The hopper body (210) is usually manufactured using quartz glass that is resistant to high heat and is transparent.

The hopper cone (220) is cone-shaped and has a diameter of the lower surface that is slightly larger than the diameter of the lower opening of the hopper body (210), so that the apex of the cone faces the inside of the hopper body (210) and completely blocks the lower opening of the hopper body (210) when mounted. It is generally made of quartz glass.

The connecting support rod (300) is connected near the cone apex of the hopper cone (220) and penetrates the interior of the hopper cone (220) and the upper cover (230) to be connected to a seed connector (not shown), thereby acting as a support wire or support rod that prevents the hopper cone (220) from falling downward due to the load of the polycrystalline silicon (400).

In addition, the connecting support rod (300) also serves to move the hopper cone (220) downward so that the lower opening of the hopper body (210) opens when filling the polycrystalline silicon (400) into the crucible (120).

When the connecting support bar (300) is made of a support wire, it is made of a high-melting point metal with high mechanical strength at high temperatures, such as molybdenum or tungsten, or an alloy thereof. When it is made in the form of a support bar, it can likewise be made of a high-melting point metal or an alloy thereof, or the same quartz glass as the hopper body (210).

The upper cover (230) is a lid that is detachably installed on the top of the hopper body (210). The upper cover (230) is usually made of quartz glass to facilitate observation, withstand high temperatures, and prevent contamination.

Meanwhile, the single crystal growth device (100) in which the hopper device (200), which is a solid raw material supply device, is installed is sealed from the outside by the lower chamber (130) and the upper chamber (140).

A crucible (120), a heater (150), and an insulator (160) are placed inside the lower chamber (130). In addition, a driving mechanism (not shown) for raising and lowering or rotating the crucible (120) may be connected to the crucible.

The upper chamber (140) extends upward from the lower chamber (130) and is cylindrically installed on the upper part of the crucible (120), and provides a space for installing a hopper device (200) or lifting a single crystal ingot through a gate (170).

Next, a method of charging polycrystalline silicon (400), which is a solid raw material, into a crucible (120) inside a single crystal growth device (100) using the hopper device (200) of this embodiment configured as described above will be described in detail.

First, the lower opening of the hopper body (210) of the hopper device (200) is blocked so that the conical apex of the hopper cone (220) faces the inside of the hopper body (210), and then the polycrystalline silicon (400), which is a solid raw material, is loaded.

At this time, the solid raw material, polycrystalline silicon (400), is usually in the form of an irregular chip or particle, with a diameter of 6 to 50 mm.

The range of the diameter of the polycrystalline silicon (400) is merely exemplary, and if the numerical precision of the hopper body (210) and the hopper cone (220) is high or the impact strength due to the size thereof is sufficiently high, the range of the diameter may be outside the range presented above.

Next, the hopper device (200) with polycrystalline silicon (400) loaded inside is mounted on the single crystal growth device (100). Specifically, the hopper cone (220) is placed downward, and the opposite end of the connecting support rod (300) is connected to the seed connector (not shown), and slowly lowered through the upper chamber (140) and the gate (170) into the lower chamber (130).

Then, the stopper (240) formed on the outer surface of the hopper body (210) is caught by the gate (170) formed by protruding on the inner wall of the upper chamber (140), so that the hopper body (210) can no longer descend and is stopped at a certain position.

At this time, the crucible (120) is filled with polycrystalline silicon (400) that has been initially charged and then melted, or contains a silicon crystal melt (110) remaining after single crystal growth.

Next, when the connecting support bar (300) is lowered further, the hopper body (210) is prevented from lowering further by the stopper (240), but the hopper cone (220) is lowered further, causing the lower opening of the hopper body (210) to open.

FIG. 3 is a cross-sectional view illustrating a state in which a solid raw material is charged into a crucible of a semiconductor single crystal growth device using a hopper device of the present invention.

As illustrated, the polycrystalline silicon (400) loaded in the hopper body (210) falls into the crucible (120) through the gap between the hopper body (210) and the hopper cone (220), thereby filling the silicon (400), which is a solid raw material.

At this time, the hopper cone (220) is lowered so that it does not directly contact the crystal melt (110) contained in the crucible (120) and has a predetermined distance. The predetermined distance is a distance that prevents the crystal melt (110) from scattering due to the falling polycrystalline silicon (400) and also prevents the liquid level of the crystal melt (110) that increases due to the filling of the polycrystalline silicon (400) from contacting the hopper cone (220). This distance can be appropriately optimized by considering the size of the solid raw material, the falling time, the volume of the crucible, etc.

The movement between the hopper body (210) and the hopper cone (220) is a relative concept. As described above, the lower opening of the hopper body (210) is opened by lowering the hopper cone (220) using the connecting support bar (300) while the hopper body (210) is fixed by the stopper (170). However, the lower opening of the hopper body (210) can also be opened by raising the hopper body (210) while the position of the hopper cone (220) is fixed.

In addition, the hopper body (210) and the hopper cone (220) and the crucible (120) may be continuously or intermittently moved during the charging of the polycrystalline silicon (400) to maintain a predetermined distance as needed, thereby increasing the distance between the hopper cone (220) and the crucible (120).

In this way, when all of the polycrystalline silicon (400) loaded in the hopper body (210) is filled into the crucible (120), the hopper device (200) including the hopper body (210) is raised toward the upper chamber (140) and taken out, and a seed for single crystal growth is connected to a seed connector (not shown) to proceed with a full-scale single crystal silicon growth process.

In general, when the diameter of polycrystalline silicon (400) is greater than 45 mm and the nugget size is loaded into the hopper device (200), glass powder is generated due to collision between the silicon (400) and the hopper body (210) or the hopper cone (220), or dust is generated due to collision between silicon (400).

In addition, when the chip size of the polycrystalline silicon (400) is 6 to 45 mm in diameter and is loaded into the hopper device (200), the generation of glass powder is relatively small, but dust is generated due to collisions between the dust from the silicon (400) itself and the silicon (400).

However, the hopper device (200) has a structural disadvantage in that it has no opening other than the lower opening of the hopper body (210), making it impossible to remove impurities and dust.

Therefore, glass powder and silicon dust generated when loading polycrystalline silicon (400) into the hopper device (200) may be introduced into the crucible of the single crystal growth device (100) together with silicon, which may cause contamination of the silicon crystal melt (110) and may be a physical cause of dislocation during single crystal growth.

Accordingly, in the present invention, glass powder and silicon dust generated when loading polycrystalline silicon (400) into a hopper device (200) are removed as much as possible and fed into a crucible of a single crystal growth device (100) together with silicon, thereby eliminating the adverse effects of solid raw materials as raw materials in the single crystal growth process.

FIG. 4 is a cross-sectional view of a hopper filter mounted on a hopper device according to an embodiment of the present invention and a mounting state diagram of the hopper filter.

Referring to the drawing, the hopper filter (500) of the present invention is manufactured according to the shape of the hopper cone (220) and is configured to be mounted on the hopper body (210).

The hopper filter (500) can be made of molybdenum, but when considering the high purity of the semiconductor single crystal ingot, the material may be quartz glass, which is the same material as the hopper body.

To explain in detail, like the hopper cone (220), the hopper filter (500) is also cone-shaped with a diameter of the lower surface slightly larger than the diameter of the lower opening of the hopper body (210) so that the apex of the cone faces the inside of the hopper body (210) so that when mounted, it is mounted in the lower opening of the hopper body (210).

In addition, the hopper cone (220) is configured to be inserted into the lower side of the hopper filter (500), and the inclination angle (θ) of the joint between the hopper filter (500) and the hopper body (210) is configured to be the same as the inclination angle (θ) of the joint between the hopper body (210) and the hopper cone (220) of FIG. 4(a) so that the hopper cone (220) is inserted along the inner surface of the hopper filter (500).

After the hopper filter (500) is mounted on the hopper body (210), when the hopper cone (220) is mounted on the hopper filter (500), the connecting support rod (300) is connected near the cone apex of the hopper cone (220) and penetrates the inside of the hopper cone (220) and the upper cover (230) to be connected to a seed connector (not shown), thereby acting as a support wire or support rod that prevents the hopper cone (220) from falling downward due to the load of the polycrystalline silicon (400).

In addition, holes (510) are formed at regular intervals or randomly on the outer surface of the hopper filter (500), so that even when the hopper filter (500) is mounted on the hopper body (210), the lower opening of the hopper body (210) forms a part that is opened through the holes (510) of the hopper filter (500), thereby enabling the removal of impurities and dust.

A hopper filter (500) having perforations (510) formed is mounted in the lower opening of the hopper body (210) so that dust and impurities generated when silicon is loaded into the hopper body (210) are discharged through the perforations (510), and then a hopper cone (220) is mounted in the lower opening of the hopper body (210) so as to completely block the lower opening.

FIG. 5 is a diagram showing a state of use for charging silicon into a semiconductor single crystal growth device using a hopper device equipped with a hopper filter according to an embodiment of the present invention. FIG. 6 is a flowchart showing a method for charging silicon into a semiconductor single crystal growth device using a hopper device equipped with a hopper filter according to an embodiment of the present invention.

Referring to the drawing, this relates to a method of loading silicon (400) into a hopper device (200) and charging it into a semiconductor single crystal growth device (100).

First, a hopper filter (400) with a perforation (510) formed in the lower opening of a vertical cylindrical hopper body (210) is mounted. (S100)

Next, the dust and impurities generated when silicon (400) to be supplied to the crucible (120) of the semiconductor single crystal growth device is loaded into the hopper body (210) are discharged through the perforations (510) of the hopper filter (400). (S200)

In addition, dust and impurities can be additionally discharged through the perforations (510) of the hopper filter by introducing gas into the hopper body (210) loaded with silicon (400). (S300)

That is, the present invention primarily filters out impurities and silicon dust generated when loading polycrystalline silicon (400) into the hopper body (210) of the hopper device (200) through the perforations (510) by using the hopper filter (400), and after the silicon (400) is loaded, a step is added to additionally remove impurities and dust remaining inside by introducing gas (e.g., argon gas, dry air, etc.) into the hopper body (210).

Next, a hopper cone (220) is mounted on the lower side of the hopper filter (500) to block the lower opening of the hopper body (S400).

Next, polycrystalline silicon (400) loaded in the hopper body (210) is charged into the crucible (120) of the semiconductor single crystal growth device (100) by opening the hopper cone (220).

That is, the connecting support rod (300) penetrates the inside of the hopper body (210) and is connected to the top of the hopper cone (220), thereby preventing the hopper cone (220) from falling down due to the load of the polycrystalline silicon (400), and also controls the falling amount and falling speed of the silicon (400) by appropriately opening the hopper cone (220).

In addition, when the hopper cone (220) of the hopper device (200) is opened and the polycrystalline silicon (400) loaded in the single crystal growth device (100) falls due to gravity, additional dust may be generated due to contact between the falling polycrystalline silicon (400). The dust generated at this time can settle between the hopper filter (400) and the hopper cone (220), thereby minimizing the dust from entering the interior of the single crystal growth device (100).

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

100: Single crystal growth device 110: Silicon crystal melt
120: Crucible 130: Lower Chamber
140: Upper chamber 150: Heater
160: Insulation 170: Gate
200: Hopper device 210: Hopper body
220: Hopper cone 230: Top cover
240: Stopper
300: Connecting support bar
400: Silicone
500: Hopper filter 510: Perforated

Claims (2)

delete A method for loading silicon into a hopper device and charging it into a semiconductor single crystal growth device,
A step of mounting a hopper filter having perforations formed in the lower opening of a vertical cylindrical hopper body;
A loading step in which dust and impurities generated when silicon to be supplied to a crucible of a semiconductor single crystal growth device is loaded into the hopper body are discharged through the perforations of the hopper filter;
A filtering step for discharging dust and impurities through the perforations of the hopper filter by introducing gas into the hopper body loaded with the silicon;
A step of mounting a hopper cone on the lower side of the hopper filter to block the lower opening of the hopper body; and
A method for charging silicon into a semiconductor single crystal growth device using a hopper device having a hopper filter, characterized in that it comprises a step of charging silicon loaded in a hopper body into a crucible of the semiconductor single crystal growth device while opening the hopper cone.

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