Apparatus for manufacturing silicon balls

Abstract

Disclosed in the present specification is an apparatus for manufacturing silicon balls, which generates spherical silicon substrates for semiconductors from silicon raw material through a melting process. The invention disclosed in the present specification may comprise: a substrate unit including a heating area in which silicon raw material is disposed; and a laser oscillator which is a laser light source and supplies, to the heating area of the substrate unit, radiant heat. Therefore, silicon balls can be manufactured by a melting process in which energy efficiency and production efficiency are considered.

Description

Silicone ball manufacturing device

[0001] The present invention relates to a silicon ball manufacturing device.

[0002] In particular, the present invention relates to a silicon ball manufacturing device that produces a spherical silicon substrate for semiconductors from a silicon raw material through a melting process.

[0003] High-purity silicon substrates are essential in a variety of applications, including semiconductor devices, solar cells, sensors, and communication modules.

[0004] In particular, as the demand for development of highly integrated devices based on three-dimensional structures has increased recently, interest in spherical semiconductor silicon substrates, i.e. silicon balls, which have excellent surface-to-volume efficiency and are advantageous for integration processes, is increasing.

[0005] In the past, a method was widely used in which silicon powder or waste silicon was heated in a high-temperature furnace to melt it and induce spontaneous sphericization of droplets during gravitational fall.

[0006] However, this method had problems such as low process efficiency due to its reliance on indirect heating based on convection heat, high energy consumption due to the need to maintain the entire space at a high temperature, and large shape deviation.

[0007] In addition, it is difficult to achieve uniform sphericity due to the difficulty in controlling heat, and the problem of increased CO2 emissions due to maintaining high heat for a long time also arises.

[0008] Accordingly, in industries where environmental regulations and production efficiency are simultaneously required, alternatives to existing methods are needed.

[0009] In particular, there is an urgent need for technological solutions that can manufacture semiconductor substrates in an environmentally friendly manner while simultaneously ensuring both shape precision and energy efficiency.

[0010] [Prior Art Literature]

[0011] [Patent Document]

[0012] (Patent Document 0001) Domestic Publication No. 2013-0075302 (Published on July 5, 2013)

[0013] The present invention, according to one embodiment, is intended to solve the above-mentioned problems and provides a silicon ball manufacturing device including a melting process that takes energy efficiency and production efficiency into consideration.

[0014] A silicon ball manufacturing device according to one embodiment may include a substrate unit including a heating region in which silicon raw material is placed, and a laser generator that supplies radiant heat to the heating region of the substrate unit using a laser light source.

[0015] At least a portion of one surface of the substrate unit on which the silicon raw material is placed may be formed as a hydrophobic treatment surface, and the hydrophobic treatment surface may be characterized by including a surface shape based on a nanostructure formed through laser texturing or etching.

[0016] The silicon raw material may be prepared in a powder state, and the substrate unit may include an alignment groove in which the silicon raw material is accommodated, and the alignment groove may be located in the heating area.

[0017] The bottom surface of the alignment groove may be formed in a hemispherical shape, and the depth of the alignment groove may be formed to be 1.1 to 1.8 times the radius of the hemispherical shape.

[0018] The above laser generator may be characterized as a laser light source, and may be one of a CO2 laser, a vertical cavity surface emitting laser, and a laser diode.

[0019] An alignment groove is formed in the above heating area, the laser generator locally irradiates a laser toward the inside of the alignment groove, and the inner surface of the alignment groove is formed of a material that reflects 70% or more of light having a wavelength of 0.8 ㎛ to 11.0 ㎛.

[0020] The laser generator may irradiate laser light to a heating area in a pulse form, and the operating time of the laser generator may include a preheating section, a melting section, and a crystallization section, and the average output of the laser generator in the melting section may be higher than that in the preheating section and the crystallization section.

[0021] A silicon ball manufacturing device according to one embodiment may further include a furnace unit in which the substrate unit moves, the furnace unit including a housing in which a preheating zone, a melting zone, and a crystallization zone are sequentially arranged therein, a conveyor that moves the substrate unit in the preheating zone, the melting zone, and the crystallization zone in that order, and the laser generator that heats the substrate unit inside the housing.

[0022] The length of the crystallization region in the conveyor length direction may be formed to be longer than the melting region or the preheating region.

[0023] According to one embodiment, the present invention can provide effects such as improved energy efficiency, improved shape precision, shortened process, and environmental friendliness by heating a local area of ​​a silicon raw material to a high temperature using a laser or radiant heat, thereby rapidly melting and spheroidizing the silicon.

[0024] FIG. 1 is a schematic drawing of a silicon ball manufacturing device according to an embodiment of the present invention.

[0025] Figures 2a to 2c are schematic diagrams illustrating each step of the melting process.

[0026] Figure 3 is a cross-sectional view of a substrate unit on which powder raw materials are placed.

[0027] Figure 4 is a cross-sectional view of an alignment groove formed in a substrate unit.

[0028] Figure 5 is a schematic diagram showing the configuration of a laser generator and a lens array.

[0029] Figure 6 is a graph explaining the output control of a laser generator.

[0030] Figure 7 is a schematic diagram showing the configuration and operating flow of the furnace unit.

[0031] Hereinafter, an embodiment of the present invention will be described in detail with illustrative drawings. However, this is not intended to limit the scope of the present invention.

[0032] When assigning reference numerals to components in each drawing, it should be noted that identical components are assigned the same numerals whenever possible, even if they appear on different drawings. Furthermore, when describing the present invention, if a detailed description of a related known configuration or function is deemed likely to obscure the gist of the present invention, such detailed description will be omitted.

[0033] Additionally, the sizes and shapes of components depicted in the drawings may be exaggerated for clarity and convenience of explanation. Furthermore, terms specifically defined in consideration of the structure and operation of the present invention are intended only to describe embodiments of the present invention and do not limit the scope of the present invention.

[0034] FIG. 1 is a schematic diagram of a silicon ball manufacturing device according to an embodiment of the present invention. FIGS. 2A to 2C are schematic diagrams illustrating each step of the melting process. FIG. 3 is a cross-sectional view of a substrate unit (100) on which powdered raw material (11) is arranged. FIG. 4 is a cross-sectional view of an alignment groove formed in the substrate unit (100). FIG. 5 is a schematic diagram illustrating the configuration of a laser generator (210) and a lens array (300). FIG. 6 is a graph explaining the output control of the laser generator (210). FIG. 7 is a schematic diagram illustrating the configuration and operation flow of a furnace unit (400).

[0035] Hereinafter, the silicon ball manufacturing device of the present invention will be described in detail with reference to FIGS. 1 to 7.

[0036] The present invention relates to a device for manufacturing a spherical silicon substrate suitable for applications such as solar cells and semiconductor modules, and includes a structure capable of preparing a silicon raw material in a powder state, melting it into a liquid state by applying heat, and then cooling it again to form a spherical solid silicon ball.

[0037] In particular, the present invention relates to a device capable of manufacturing a spherical solid silicon ball by preparing a silicon raw material in a powder state, applying heat to change the phase into a liquid state, and then cooling it again.

[0038] That is, the silicon ball manufacturing device of the present invention has a structure capable of forming silicon into a spherical shape through a series of processes of melting powder raw materials into a liquid state through a heat process and then crystallizing them into a solid state.

[0039] As illustrated in FIG. 1, the silicon ball manufacturing device of the present invention may include a substrate unit (100) and a laser generator (210).

[0040] The substrate unit (100) may be formed in the shape of a plate made of a ceramic material, and a heating area (110) on the upper surface of which a silicon raw material is placed may be provided. The silicon raw material may be prepared in a powder form and may be spread over the heating area (110) or placed in the form of a certain amount of lumps.

[0041] The heating area (110) is a region that receives heat from the laser generator (210), and the laser generator (210) is configured as a laser light source and can supply radiant heat to a selected local area on the substrate unit (100). At this time, the region where the light is irradiated becomes the heating area (110). A plurality of heating areas (110) can be formed in the substrate unit (100), and silicon powder can be precisely divided and placed in each heating area (110).

[0042] To ensure particle size accuracy, silicon powder is preferably treated with electrostatic discharge (ESD) before use. Since static electricity can cause particle agglomeration or uneven particle distribution, equipment such as a de-electrostatic hopper or ionizer can be used to remove the ESD. This allows for uniform powder distribution across multiple heating zones (110), resulting in the simultaneous production of silicon balls of uniform size.

[0043] As illustrated in FIGS. 2A to 2C, at least a portion of one surface of the substrate unit (100) on which the silicon raw material is disposed can be formed as a hydrophobic surface. This hydrophobic surface is implemented by imparting a nanostructure through mechanical processing such as laser texturing or etching, thereby ensuring hydrophobicity without a separate chemical coating. This mechanical method has the advantage of stably maintaining hydrophobicity even in high-temperature environments.

[0044] As the surface of the substrate unit (100) is configured as a hydrophobic treatment surface, a wetting angle with the hydrophobic surface is formed while the silicon raw material changes from a powder raw material (11) state to a liquid raw material (12) and a solid raw material (13) during the thermal process. Through this, the silicon raw material naturally takes on a spherical shape, and as a result, evenly formed silicon balls can be obtained.

[0045] Specifically, as illustrated in Fig. 2a, when a powder raw material (11) is placed on a hydrophobic treatment surface in a lump or dispersed form and heated using a heat source such as a laser, the powder raw material (11) undergoes a phase transition into a liquid raw material (12) and forms a wetting angle with the hydrophobic surface. When cooling occurs in this state, the liquid silicone solidifies into a spherical solid raw material (13).

[0046] In addition, the substrate unit (100) may be formed of a ceramic material such as alumina (Al2O3), aluminum nitride (AlN), silicon nitride (Si3N4), silicon carbide (SiC), or aluminum titanate (AT) in consideration of high temperature stability, thermal shock resistance, hydrophobicity, chemical inertness, etc. These materials can maintain stable mechanical properties without structural deformation or decomposition even at high temperatures of about 1400 to 1600°C, have excellent resistance to repeated thermal shocks, and have little reaction with silicon raw materials or reaction byproducts, thereby preventing process contamination.

[0047] In particular, by forming a nanostructure directly on the substrate surface without chemical surface treatment, hydrophobicity can be continuously maintained even in a high-temperature environment, thereby preventing aggregation or residue of silicon raw materials and consequently increasing the shape stability of spherical silicon balls.

[0048] As illustrated in FIG. 3, alignment grooves may be formed on the upper surface of the substrate unit (100) at corresponding positions of the heating zones (110). When a plurality of heating zones (110) are formed, a plurality of alignment grooves (111) may also be provided to correspond to each heating zone (110).

[0049] The alignment groove is a structure for accommodating silicon powder raw material (11). The silicon raw material in a powder state is inserted therein, and when laser light irradiated from a laser generator (210) reaches the inside of the alignment groove (111), the silicon raw material can be phase-transformed into a liquid state inside the alignment groove (111). Therefore, the substrate unit (100) may include an alignment groove in which the silicon raw material in a powder state is accommodated, and the alignment groove may be arranged to correspond to the heating region (110).

[0050] Specifically, the entrance of the alignment groove can be formed to match the shape and position of the heating zone (110), and in this case, the entrance portion of the alignment groove can become the heating zone (110). In this case, one alignment groove can be matched one-to-one with one heating zone (110).

[0051] In another embodiment, a plurality of alignment grooves may be arranged in one heating area (110), and in this case, the alignment grooves may be arranged in a matrix shape or the like on the inside of the heating area (110). A 1:1 or 1:many matching method between the heating area (110) and the alignment grooves (111) may be designed in consideration of the light irradiation range of the laser oscillator (210), the irradiation method (e.g., scanning or multi-irradiation), the output specifications of the light source, etc.

[0052] As illustrated in Fig. 4, the bottom surface of the alignment groove may be formed in a hemispherical shape, and the side wall may be extended in a cylindrical shape. At this time, if the radius of the hemispherical shape of the bottom surface of the alignment groove (111) is defined as D1, the total depth of the alignment groove may be defined as the sum of the depth D1 corresponding to the hemispherical area and the depth D2 of the cylindrical side wall in a straight shape formed thereon.

[0053] The silicon ball manufacturing device of the present invention sets the side wall depth D2 to a range of about 10% to 30% of the hemispherical radius D1, thereby preventing silicon powder from overflowing to the upper portion of the alignment groove and enabling the silicon ball formed after the thermal process to smoothly escape from the alignment groove. Accordingly, it is preferable that the total depth of the alignment groove be formed to be about 1.1 to 1.8 times D1.

[0054] Additionally, the inner surface of the alignment groove can be formed with a hydrophobic treatment surface, which allows the silicon balls to be easily separated from the surface of the alignment groove without remaining on it after the melting and solidification process. Furthermore, a wetting angle is formed between the cylindrical side wall and the silicon raw material, which helps maintain the silicon ball's shape as close to a precise sphere as possible through surface tension balance during the solidification process.

[0055] The laser generator (210) is a laser light source in the IR region, and may be one of a CO2 laser, a vertical-cavity surface-emitting laser (VCSEL), and a laser diode (LD).

[0056] Vertical-cavity surface-emitting lasers (VCSELs) can be easily applied in various ways because they are free from the installation of optical mirrors and lenses.

[0057] In the case of laser diodes (LD), it is very effective in increasing the uniformity of the laser when using a laser output beam in the shape of a square or polygon by manufacturing multiple multi-lasers, so it is advantageous when creating a laser beam in the shape of a square of 30 cm or larger.

[0058] The laser generator (210) locally irradiates a laser toward the inside of the alignment groove (111), and the inner surface of the alignment groove can be formed of a material that reflects more than 70% of light having a wavelength of 0.8 μm to 11.0 μm, taking into account the output wavelength of a CO2 laser, a vertical cavity surface emitting laser, a laser diode, etc. that can be used as a laser generator. At this time, the light irradiated into the alignment groove (111) can be reflected on the inner wall of the alignment groove and irradiated again to the silicon raw material.

[0059] In another embodiment, the inner surface of the alignment groove may be coated with a material that absorbs 70% or more of light having a wavelength of 0.8 μm to 11.0 μm, taking into account the output wavelength of the CO2 laser. The material coated on the inner surface of the alignment groove can effectively absorb light from the laser oscillator (210), convert it into heat energy, and indirectly transfer heat to the silicon raw material.

[0060] As illustrated in FIG. 5, the silicon ball manufacturing device of the present invention may further include a lens array (300). The lens array (300) is arranged between the laser generator (210) and the substrate unit (100), and is configured to branch and irradiate laser light emitted from the laser generator (210) to each of a plurality of heating areas (110) or alignment grooves (111).

[0061] The lens array (300) is an optical member composed of a plurality of lens elements, and can perform the function of focusing or diffusing laser light irradiated through a single or multiple light sources into a plurality of local areas. Through this, the laser generator (210) can perform uniform and precise light irradiation on a plurality of alignment grooves on the substrate unit (100), and by precisely controlling the temperature distribution of the heating area (110), the melting and spheroidization process of the silicon raw material can be efficiently performed.

[0062] The laser generator (210) can irradiate pulse-shaped laser light to the heating region (110), and as illustrated in FIG. 6, the operating time of the laser generator (210) can be divided into a preheating section (A), a melting section (B), and a crystallization section (C). At this time, the average output in the melting section (B) can be set relatively high compared to the preheating section (A) and the crystallization section (C).

[0063] Here, average power is defined as the total energy radiated per unit time, based on the pulse repetition rate, pulse energy, and pulse width. For example, if the energy per pulse is constant, an increase in the pulse repetition rate increases the average power, which directly affects the total heating energy.

[0064] This pulse-based average power control method can play a crucial role in controlling the phase transformation and crystallization of silicon raw materials. Specifically, by irradiating a pulsed laser with a high average power in the melting region (B), silicon powder can be rapidly and completely melted. In the subsequent crystallization region (C), the average power can be lowered to control the solidification rate, thereby preventing excessive amorphous silicon from forming and inducing a microcrystalline or polycrystalline structure. This can contribute to improving the physical strength and electrical properties of the ultimately manufactured silicon balls.

[0065] More specifically, in the preheating section (A), the average output may be set to gradually increase over time, and in the crystallization section (C), the average output may be set to gradually decrease. Furthermore, to ensure the crystal quality of the silicon, it is preferable that the duration of the crystallization section (C) be longer than that of the preheating section (A) and the melting section (B). This enables stable solidification during the crystallization process, and allows for the production of silicon balls with a more uniform crystal structure.

[0066] As illustrated in FIG. 7, a silicon ball manufacturing device according to one embodiment of the present invention may further include a furnace unit (400). The furnace unit (400) has a structure in which a substrate unit (100) can move inside, and provides a series of processes in which a silicon raw material is heat-treated while the substrate unit (100) sequentially passes through a preheating zone (S1), a melting zone (S2), and a crystallization zone (S3).

[0067] The furnace unit (400) includes a housing (440) in which a preheating zone (S1), a melting zone (S2), and a crystallization zone (S3) are sequentially arranged, a conveyor (430) for moving the substrate unit (100) along these zones, and a laser generator (210) or an auxiliary heating unit (220) for supplying heat to each zone. The housing (440) has an inlet (410) at one end through which the substrate unit (100) is introduced, and an outlet (420) at the other end through which heat is discharged, and the preheating zone (S1) is adjacent to the inlet (410), the crystallization zone (S3) is adjacent to the outlet (420), and the melting zone (S2) is arranged between the two zones.

[0068] In the preheating zone (S1) and the crystallization zone (S3), an auxiliary heating unit (220) is used to heat the silicon raw material to a relatively low temperature, and in the melting zone (S2), a laser generator (210) for high-temperature processing directly heats the silicon raw material. That is, in the preheating zone (S1) and the crystallization zone (S3), an auxiliary heating unit (220) is provided, and in the melting zone (S2), a laser generator (210) alone or a laser generator (210) and an auxiliary heating unit (220) may be provided together.

[0069] The conveyor (430) may include a conveyor belt that moves the substrate unit (100) linearly, and the length of the crystallization zone (S3) may be formed to be longer than the preheating zone (S1) or the melting zone (S2).

[0070] In addition, the auxiliary heating unit (220) has a preheating area ( S1 ) and a crystallization zone (S3), and may include various heat supply methods as a heat source for precisely controlling the temperature of the silicon raw material. Specifically, the auxiliary heating unit (220) may be implemented with a ceramic heater that emits mid-infrared or far-infrared rays, and such a ceramic heater can maintain a uniform temperature over a wide area and can operate stably even at 200°C or higher, making it suitable for high-temperature heat processes.

[0071] In another embodiment, the auxiliary heating unit (220) may be implemented as a hot plate method or a thermo plate method that contacts the lower part of the substrate unit to conduct heat, in which case a stable initial temperature distribution can be provided for the entire area of ​​the substrate. In addition, it may also be implemented as a hot air heater method that heats the silicon raw material in a non-contact manner by circulating high-temperature hot air. The hot air method can maintain a constant temperature environment through internal convection, and is advantageous in implementing a condition of gradual cooling in the crystallization region (S3).

[0072] The configuration of the auxiliary heating unit (220) as described above can contribute to improving the structural stability and electrical properties of the silicon ball ultimately manufactured by preventing the silicon raw material from becoming excessively amorphous and inducing a stable phase transition into a microcrystalline or polycrystalline structure.

[0073] This configuration enables precise control of the thermal environment for each process step, thereby stably inducing a phase change of the silicon raw material, and provides process efficiency suitable for mass production through a structure capable of continuously processing a plurality of substrate units (100). In particular, by increasing the length of the crystallization region (S3), the silicon liquid phase is slowly solidified for a sufficient period of time, thereby suppressing excessive amorphous formation and inducing a microcrystalline or polycrystalline structure, thereby improving the electrical characteristics and physical strength of the final silicon ball.

[0074] Although the present invention has been illustrated and described with respect to specific embodiments, it will be apparent to those skilled in the art that the present invention can be variously improved and modified without departing from the technical spirit of the invention as defined by the following claims.

[0075] [Explanation of symbols]

[0076] 11...powder raw materials

[0077] 12...Liquid raw materials

[0078] 13...High-quality raw materials

[0079] 100...board unit

[0080] 110...heating zone

[0081] 111...Sort Home

[0082] 120...hydrophobic treated surface

[0083] 210...laser generator

[0084] 220... auxiliary heating unit

[0085] 300...lens array

[0086] 400...furnace unit

[0087] 410...inlet

[0088] 420...Outlet

[0089] 430...Conveyor

[0090] 440...Housing

[0091] A...warm-up section

[0092] B... melting zone

[0093] C...crystallization zone

[0094] D1...first depth

[0095] D2...second depth

[0096] S1...preheating zone

[0097] S2...melting zone

[0098] S3...crystallization zone

[0099] The silicon manufacturing device of the present invention uses a laser or radiant heat to heat a localized area of ​​silicon raw material to a high temperature, thereby rapidly melting and spherizing the silicon. This can increase productivity through improved energy efficiency, improved shape precision, and a shorter process time. Furthermore, it can also ensure environmental friendliness by reducing CO2 emissions.

Claims

1. In a device for manufacturing a silicone ball, a substrate unit including a heating zone in which silicon raw material is placed; and A laser generator that supplies radiant heat to the heating area of ​​the above substrate unit as a laser light source. A silicon ball manufacturing device comprising:

2. In paragraph 1, At least a portion of one surface of the substrate unit on which the silicon raw material is placed is formed as a hydrophobic treatment surface, The hydrophobic treatment surface includes a surface shape based on a nanostructure formed through laser texturing or etching. A silicon ball manufacturing device characterized by:

3. In paragraph 1, The above silicone raw material is prepared in powder form, The above substrate unit Including an alignment groove in which the above silicon raw material is accommodated, The above alignment groove is located in the above heating area. A silicon ball manufacturing device characterized by:

4. In paragraph 3, The bottom of the above alignment groove is formed in a hemispherical shape, The depth of the above alignment groove is formed to be 1.1 to 1.8 times the radius of the hemispherical shape. A silicon ball manufacturing device characterized by:

5. In paragraph 1, The above laser generator is a laser light source, and is one of a CO2 laser, a vertical cavity surface emitting laser, and a laser diode. A silicon ball manufacturing device characterized by:

6. In paragraph 5, An alignment groove is formed in the above heating area, The above laser generator locally irradiates the laser toward the inside of the alignment groove, The inner surface of the above alignment groove is formed of a material that reflects more than 70% of light with a wavelength of 0.8 ㎛ to 11.0 ㎛. A silicon ball manufacturing device characterized by:

7. In paragraph 5, The above laser generator irradiates laser light to the heating area in the form of pulses, The operating time of the above laser generator includes a preheating section, a melting section, and a crystallization section, The average output of the above laser generator in the above melting section is higher than that of the above preheating section and the above crystallization section. A silicon ball manufacturing device characterized by:

8. In paragraph 1, The above substrate unit further includes a furnace unit that moves inside, The above furnace unit A housing in which a preheating zone, a melting zone, and a crystallization zone are sequentially arranged inside, A conveyor that moves the substrate unit to the preheating zone, the melting zone, and the crystallization zone in that order; Including the laser generator that heats the substrate unit inside the housing A silicon ball manufacturing device characterized by:

9. In paragraph 8, The length of the crystallization region in the conveyor length direction is formed to be longer than the melting region or the preheating region. A silicon ball manufacturing device characterized by:

Images