Method for manufacturing cylindrical silicon ingot

Abstract

SOLUTION: To provide a method for manufacturing a cylindrical silicon ingot 30 comprising steps of: supplying a silicon raw material 10 to the inside of a crucible 100 and heating the crucible to melt the silicon raw material; supplying a seed crystal 20 having one end fastened to a seed shaft 21 to the inside of the crucible; and moving the seed crystal from the lower part of the crucible to the upper part by raising the seed crystal while rotating the crucible in one direction using the seed shaft as a reference and rotating the seed shaft in the other direction.EFFECT: The growth of a ring shaped seed crystal can manufacture a cylindrical silicon ingot, and the formation of the cylindrical silicon ingot having an inner diameter can manufacture a wafer retainer ring from the ingot without core ring work. Accordingly, the reduction of the amount of a raw material input into a crucible can reduce a cost price; the minimization of worker injuries and the reduction of process steps can improve a process speed and efficiency, not only minimize a defective rate but also reduce manufacturing cost.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for producing an ingot, and more particularly to a method for producing a cylindrical silicon ingot. [Background technology]

[0002] Silicon ingot manufacturing technology for producing wafers, which are the basic material for semiconductor devices, remains a vital part of the semiconductor industry, and is used to manufacture 12-inch wafers as well as wafer retainer rings, showerheads, and other products.

[0003] Most of the silicon ingots produced are used in the form of wafers. Wafers are made by slicing single crystal pillars (ingots) made by growing silicon (Si) or gallium arsenide (GaAs) using the Czochralski method, etc., through a wire process, and then polishing them to use them as substrates for manufacturing chips.

[0004] The showerhead is manufactured to be thicker than the wafer and has fine through holes formed on its entire surface except for the edges to allow gas to flow during semiconductor manufacturing.

[0005] In this way, the wafer and showerhead are manufactured in a cylindrical shape with no internal diameter, and only have the dimensions of an outer diameter and thickness.

[0006] However, in order to manufacture a wafer retaining ring having an inner diameter using a columnar ingot manufactured by the conventional silicon ingot manufacturing technology, various problems have arisen due to the additional process of removing the inner core. Specifically, before performing the coring process to remove the inner core to form the inner diameter of the wafer retaining ring, an additional cutting process is required to reduce the length of the ingot to fit the coring process, and if the hole cup of the core cannot maintain its perpendicularity while penetrating the ingot during the coring process, a problem occurs in which the size of the inner diameter is defective. To solve this, if the ingot is turned upside down and the coring process is performed twice, an additional process step must be added, and even if this is added, it is still not easy to align the surface accurately. In other words, there is a risk of a high defect rate during the ingot coring process. In addition, the inner material removed after the coring process is discarded in its entirety because it is too large to be used in many applications, resulting in a large amount of raw material being wasted.

[0007] In order to solve the above-mentioned problems, the present invention provides a method for manufacturing a cylindrical silicon ingot. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Republic of Korea Patent No. 10-1631368 (registered on June 10, 2016) [Patent Document 2] Republic of Korea Patent No. 10-1714751 (registered on March 3, 2017) Summary of the Invention [Problem to be solved by the invention]

[0009] A technical object of the present invention is to provide a method for manufacturing a cylindrical ingot that can manufacture a wafer retainer ring having an inner diameter without a coring operation.

[0010] Another technical object of the present invention is to provide a method for producing a cylindrical ingot by growing a ring-shaped seed crystal. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention provides a method for producing an ingot, comprising the steps of: supplying a silicon raw material into a crucible and heating the crucible to melt the silicon raw material; fastening one end of a seed crystal having a ring-shaped cross section to a seed shaft and supplying it into the crucible; and rotating the crucible in one direction based on the seed shaft and moving the seed crystal from the bottom to the top of the crucible by the seed shaft rotating in the other direction and rising. Effect of the Invention

[0012] According to the present invention, a cylindrical silicon ingot can be produced for growing a ring-shaped seed crystal.

[0013] In accordance with the present invention, a cylindrical silicon ingot is formed having an inner diameter, allowing a wafer retainer ring to be manufactured from the ingot without a coring operation.

[0014] According to the present invention, since the wafer retainer ring is manufactured from a cylindrical ingot, the amount of raw material put into the crucible can be reduced, thereby reducing the cost.

[0015] According to the present invention, by producing a cylindrical ingot using a small amount of raw material, the size of the crucible is reduced, and accordingly, the size of the refractory material and heater surrounding the crucible is also reduced, thereby minimizing the construction costs of the manufacturing equipment.

[0016] According to the present invention, a cylindrical silicon ingot having an inner diameter is formed, eliminating the need for a coring process, thereby minimizing injury to workers, reducing process steps to improve process speed and efficiency, minimizing the defect rate, and reducing manufacturing costs. [Brief description of the drawings]

[0017] [Figure 1] 1 is a flow chart of a method for producing a cylindrical ingot according to the prior art. [Diagram 2] 1 is a flow chart of a method for producing a cylindrical ingot according to an embodiment of the present invention. [Diagram 3] 1A and 1B are perspective and cross-sectional views of a seed crystal according to an embodiment of the present invention. [Figure 4] 1 is a perspective view of an ingot produced according to the prior art and an embodiment of the present invention; FIG. [Diagram 5] 1 is a diagram showing steps of a method for manufacturing a cylindrical ingot according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The objects and advantages of the present invention will become clearer through the detailed description below, but the objects and advantages of the present invention are not limited to the following description. In addition, in the description of the present invention, if it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted.

[0019] Generally, single crystal growth involves growing a crystal by contacting a single crystal seed with a polycrystal melt.

[0020] At this time, the characteristics of the single crystal are formed depending on the seed used, and unit crystals are formed based on this.

[0021] The seed is generally provided in the form of a square rod having a width, length and length of 10 mm and a length of 100 mm, and the seed is connected to the upper rotating shaft of a crucible and brought into contact with the molten liquid to grow into an ingot.

[0022] In the present invention, instead of the general square rod-shaped seed as described above, a cylindrical ingot is manufactured by growing a crystal using a seed having a ring-shaped cross section with an inner diameter.

[0023] Furthermore, the present invention is not limited to growing a polycrystalline molten solution, and can be carried out using any silicon raw material, regardless of whether it is a single crystal or a polycrystal.

[0024] Specifically, a seed shaft to which the seed is fastened and a crucible shaft supporting a crucible containing molten material rotate in opposite directions, and the seed shaft is pulled upward to form a single crystal ingot.

[0025] At this time, if the ingots become larger due to the capillary effect, the inner diameter will disappear and the lower part will become a rod shape with no inner diameter, but this can be prevented by adjusting the rotation speed and pulling speed of the seed shaft.

[0026] In addition, since the ingot manufacturing method according to the present invention uses a ring-shaped seed crystal, the rotation speed and pulling speed of the ingot are increased by 10 to 40% compared to the conventional manufacturing method, and the ingot can be grown at a shape that eliminates the inner diameter.

[0027] Hereinafter, a method for manufacturing a cylindrical ingot according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0028] In the drawings, in order to clearly disclose the present invention, parts that are not related to the present invention are omitted, and the same or similar reference numerals in the drawings indicate the same or similar components.

[0029] This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0030] FIG. 1 is a flow chart of a method for producing a cylindrical ingot according to the prior art, and FIG. 4 is a perspective view of an ingot produced according to the prior art and an embodiment of the present invention.

[0031] Referring to FIG. 1, the method for manufacturing a cylindrical ingot according to the prior art includes a melting step (S100), a supplying step (S200) and a growing step (S300) like the method for manufacturing an ingot according to an embodiment of the present invention.

[0032] However, since the conventional technique uses a seed crystal 20' in the shape of a square rod, it produces a cylindrical ingot 30' having only a first diameter d1 which is the outer diameter, rather than a cylindrical ingot having an inner diameter d3.

[0033] Specifically, in Fig. 4 1, an ingot 30' produced by the ingot production method according to the prior art is produced in a cylindrical shape having a first diameter d1.

[0034] On the other hand, in Fig. 4 1, an ingot 30 produced by a method for producing an ingot according to an embodiment of the present invention is produced in a cylindrical shape having a second diameter d2 and an inner diameter d3.

[0035] Typically, the wafer retainer ring used in the 12 inch wafer manufacturing process has an inner diameter of 296 mm, so it would be preferable for the ingot 30 manufactured by the ingot manufacturing method according to one embodiment of the present invention to also be formed so that the inner diameter d3 is 296 mm.

[0036] Also, the second diameter d2 would preferably be formed to have a value of 350 mm.

[0037] Hereinafter, the shape of a seed crystal and a method for manufacturing an ingot according to an embodiment of the present invention for manufacturing the cylindrical ingot as described above will be described in detail with reference to FIGS. 2, 3 and 5. FIG.

[0038] FIG. 2 is a flowchart of a cylindrical ingot manufacturing method according to one embodiment of the present invention, FIG. 3 is an oblique view and a cross-sectional view of a seed crystal according to one embodiment of the present invention, and FIG. 5 is a stage diagram of a cylindrical ingot manufacturing method according to one embodiment of the present invention.

[0039] First, referring to FIG. 5, a cylindrical ingot manufacturing method according to one embodiment of the present invention includes a melting step (S100), a supplying step (S200) and a growing step (S300), and the growing step (S100) may be performed including a first speed control step (S310) and a second speed control step (S320).

[0040] The melting step (S100) is a step of supplying a silicon raw material 10 into a crucible 100 and heating the crucible 100 to melt the silicon raw material 10, and the supplying step (S200) is a step of supplying a seed crystal 20, one end of which is fastened to a seed shaft 21, into the crucible.

[0041] In this case, it is preferable that the seed crystal 20 has a ring-shaped cross section and its lower surface has an inner diameter in the range of 270 to 290 mm and an outer diameter in the range of 350 to 600 mm.

[0042] A specific shape of the seed crystal 20 will be described later with reference to FIG.

[0043] The growth step (S300) is a step in which the crucible 100 rotates in one direction based on the seed axis 21, and the seed axis 21 rotates in the other direction and rises, thereby moving the seed crystal 20 from the bottom to the top of the crucible 100.

[0044] As a preferred embodiment, the growth step (S300) may be performed to further include a first speed adjustment step (S310) of adjusting the speed at which the seed shaft 21 rotates in the other direction so that the seed crystal 20 forms an ingot according to a preset shape, and a second speed adjustment step (S320) of adjusting the speed at which the seed shaft 21 moves from the bottom to the top of the crucible 100.

[0045] At this time, it is preferable that the rotation speed is in the range of 10 to 30 rpm and the pulling speed is in the range of 0.3 to 0.8 mm / min.

[0046] In this manner, by providing the first speed control step (S310) and the second speed control step (S320), it is possible to prevent the ingots 30 growing in the growth step (S300) from becoming larger than each other due to the capillary effect, which would cause the inner diameter to disappear, and to form the ingot 30 according to a preset shape.

[0047] In order to form a cylindrical ingot 30 having an inner diameter, the seed crystal 20 according to an embodiment of the present invention is provided so that its cross section has a ring shape.

[0048] Specifically, the cross section of the seed shaft 21 cut perpendicularly to the longitudinal direction thereof has a ring shape.

[0049] More specifically, the seed crystal 20 is shown in FIG. 3, the upper surface of the flattened hemispherical shape may be implemented as shown in FIG. 3, may be implemented to have a frustoconical profile, as shown in FIG. <c>As shown in FIG.

[0050] Thus, the seed crystal 20 of the present invention is not limited in its external shape, but may simply be provided with a cavity formed therein and with a cross section cut perpendicular to the longitudinal direction of the seed axis 21 having a ring shape.

[0051] Furthermore, since the seed shaft 21 rotates, the cross section of the seed crystal 20 does not have to be ring-shaped, but may be formed so that a cavity is formed inside and the cross section has an outer diameter and an inner diameter.

[0052] It may also be preferable for the seed crystal 20 to be provided with one or more hollows H passing through at least one of the periphery or top surface.

[0053] Specifically, the seed crystal 20 is< / c> and 3, when the seed crystal 20 has a hemispherical or truncated conical shape, the hollow H is formed so as to penetrate the peripheral surface of the seed crystal 20. <c>In the case where the seed crystal 20 has a cylindrical outer shape as shown in FIG.

[0054] However, without being limited thereto, the hollow H can maintain a vacuum atmosphere inside the ingot formed by discharging gas generated during ingot growth through the hollow H, thereby preventing bubbles from being generated on the surface of the ingot.

[0055] At this time, the hollow H may be formed like a pin hole, but is not limited thereto, and may be formed to have various shapes and diameters.

[0056] In addition, it is preferable that the hollow H is provided so as to be formed at a position symmetrical with respect to the center of the seed crystal so that the seed crystal can rotate while maintaining balance during the process of growing an ingot and form an ingot of a uniform shape.

[0057] The above-described preferred embodiments of the present invention have been disclosed for illustrative purposes, and those skilled in the art having ordinary skill in the art will be able to make various modifications, changes and additions within the spirit and scope of the present invention, and such modifications, changes and additions should be understood to fall within the scope of the following claims.

[0058] Furthermore, since various substitutions, modifications and alterations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains without departing from the technical spirit of the present invention, the present invention is not limited to the above-described embodiments and the attached drawings.

[0059] In the exemplary system described above, the method is described based on a flowchart with a series of steps or blocks, but the invention is not limited to the order of steps, and some steps may occur in a different order or simultaneously with other steps described above. Also, those skilled in the art will understand that the steps shown in the flowcharts are not exclusive, and other steps may be included or one or more steps of the flowcharts may be omitted without affecting the scope of the invention. [Explanation of symbols]

[0060] 100: Crucible 10: Silicon raw materials 20: Seed crystal 21: Seed axis 30: Ingot d1: 1st diameter d2: 2nd diameter d3: inner diameter H:Hollow< / c>

Claims

1. A melting step (S100) of supplying a silicon raw material into a crucible and heating the crucible to melt the silicon raw material; A step (S200) of fastening one end of a seed crystal having a ring-shaped cross section to a seed shaft and supplying the seed crystal into the crucible; and A growing step (S300) in which the crucible rotates in one direction based on the seed axis and the seed axis rotates in the other direction while ascending, thereby moving the seed crystal from the bottom to the top of the crucible; Including, The seed crystal is A method for producing a cylindrical ingot, characterized in that the ingot has one or more hollows extending through its periphery.

2. The growing step (S300) includes: The seed crystal is caused to form an ingot according to a preset shape. A first speed adjusting step (S310) of adjusting the speed at which the seed shaft rotates in the other direction; and A second speed adjusting step (S320) of adjusting a speed at which the seed shaft moves from the lower part to the upper part of the crucible; 2. The method of claim 1, further comprising:

3. The speed at which the seed shaft rotates in the other direction is in the range of 10 to 30 rpm; 2. The method for producing a cylindrical ingot as claimed in claim 1, wherein the speed at which the seed axis moves from the bottom to the top of the crucible is in the range of 0.3 to 0.8 mm / min.

4. The lower surface of the seed crystal is An inside diameter in the range of 270-290 mm; and External diameter in the range of 350-600 mm; 2. The method for producing a cylindrical ingot according to claim 1, comprising the steps of:

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