TWI465616B - Casting device for directional solidification, manufacturing method of ingot, platy seeding structure - Google Patents

Description

Directional solidification device, method for manufacturing tantalum ingot, and template crystal seeding structure

The present invention relates to a solidifying apparatus, a seeding structure, and a method for producing a tantalum ingot, and more particularly to a method of manufacturing a tantalum ingot, a templated seeding structure, and a tantalum ingot using a seeding structure.

Due to the advent of the electronic age, electronic products have received a lot of attention, so wafer materials have become a product of the semiconductor industry and the optoelectronic industry. There are many ways to grow wafers, such as the Floating Zone Method, the Laser Heated Pedestal Growth, and the Czochralski Method. The equipment used is different for each crystal growth method.

Solar cells are a kind of semiconductors, so they are also called solar wafers. Silicon is the representative of the raw materials of solar cells. The principle of power generation is to convert solar energy into electricity. Solar PV Cell has a wide variety of wafer materials, which can be roughly divided into single crystal germanium, polycrystalline germanium, amorphous germanium, and other non-antimony materials. Among them, single crystal germanium and polycrystalline germanium are the most common.

However, before the formation of the solar wafer, the crucible must be solidified in a crucible to form a crucible ingot, which is then cut to form a wafer. However, when the soup is solidified, the crystal grains of the crucible soup located at the bottom of the crucible are often large, which will cause more defects inside the finally formed crucible ingot, thereby affecting the wafer conversion efficiency after cutting.

Therefore, the inventor felt that the above-mentioned deficiency could be improved, and he devoted himself to research and cooperated with the application of theory, and finally proposed a reasonable and effective design. The invention described above is missing.

An embodiment of the present invention provides a directional solidification apparatus, a bismuth ingot manufacturing method, and a template crystal seeding structure for making the inside of the formed bismuth ingot less defective.

The embodiment of the present invention provides a directional solidification device for solidifying a smelting soup, the directional solidification device comprising: a crucible comprising an inner bottom surface and a ring side surface connected to the inner bottom surface; and a seeding structure, The bottom edge of the ring is disposed on the bottom surface of the crucible, and the distance from the top edge of the ring is at least five times the distance from the inner bottom surface of the seed crystal structure, and the seed crystal structure comprises a plurality of layers. a seeding particle on the bottom surface of the crucible, and the seeding particles and the inner bottom surface define a nucleation space for suppressing the melting in the nucleation space when solidifying the crucible The size of the grain growth of the soup.

Preferably, the seeding particles are at least one of carbide particles, graphite particles and nitride particles.

Preferably, the seeding particles are respectively spherical, and the seeding particles are arranged next to each other.

Preferably, the seed crystal particles have substantially the same diameter, and each of the seed crystal particles has a diameter of approximately 0.5 mm to 40 mm.

Preferably, the seed crystal particles are arranged in at least two layers.

Preferably, the seed crystal particles are respectively columnar, and the seed crystal particles are arranged in a matrix at intervals.

Preferably, the seed crystal particles are substantially identical square pillars, and each of the seed crystal particles has a cross-sectional side length of approximately 0.5 mm to 40 mm.

An embodiment of the present invention further provides a method for manufacturing a bismuth ingot using the above seeding particles, the method comprising: providing a crucible, and taking a specific amount of seed crystal particles according to an area of a bottom surface of the crucible; The seeding particles are arranged in a layered manner on the bottom surface of the crucible, and the seeding particles are surrounded by the bottom surface of the crucible to define a nucleation space; a crucible is placed in the crucible, and Heating to melt the crucible melt to form a crucible; solidifying the crucible soup from the bottom surface of the crucible, and the crucible soup located in the nucleation space passes through the restriction of the nucleation space to solidify The size of the grain growth is inhibited; the enamel melt is solidified to form a half finished product, wherein the semi-finished product defines a cutting surface substantially parallel to the inner bottom surface of the crucible, and the semi-finished product is located in the cutting surface and the crucible The portion between the bottom surfaces is defined as a template-type seeding structure, the template-type seeding structure comprising the seeding particles and a solid crucible connecting the seeding particles, and the other portion of the semi-finished product is defined as a Ingot; and take out the half Product and cut along the cut surface of the silicon ingot to form the template type and seeding structure.

Preferably, the step of manufacturing the bismuth ingot further comprises: providing another crucible substantially the same as the crucible; placing the template-type seeding structure on the bottom surface of the other crucible; and Another crucible of substantially the same melt is placed in the other crucible and heated to melt the further crucible and the solid crucible of the template-type seeding structure to form another crucible.

The embodiment of the invention further provides a template-type seeding structure formed in the above-described method for manufacturing a tantalum ingot.

In summary, the directional solidification device, the bismuth ingot manufacturing method, and the template-type seeding structure provided by the embodiments of the present invention facilitate the solidification of the grains in the crucible at the bottom of the crucible having smaller grains. The diameter, in turn, reduces the internal defects of the bismuth ingot formed by the solidification of the smelting soup.

The detailed description of the present invention and the accompanying drawings are to be understood by the claims The scope is subject to any restrictions.

[First Embodiment]

1 to FIG. 6, which is a first embodiment of the present invention, wherein FIG. 1, FIG. 4, and FIG. 5 are schematic cross-sectional views of the embodiment, and FIG. 2, FIG. 3, and FIG. A schematic top view of an example.

Referring to Figures 1 and 2, this embodiment is a directional solidification apparatus 100 that includes a crucible 110 and a seeding structure 120.

The crucible 110 has a hollow square column shape and includes an inner bottom surface 111 and a ring side surface 112 connected to the inner bottom surface 111. Thereby, the formed space is surrounded by the inner bottom surface 111 of the crucible 110 and the ring side surface 112 to accommodate a molten soup 200 (see FIG. 9).

The seeding structure 120 includes a plurality of seeding particles 121, which may be at least one of carbide particles, graphite particles and nitride particles.

Among them, the preferred choice of carbide particles is tantalum carbide particles, and the preferred choice of nitride particles is tantalum nitride particles, but in practical applications, as long as the material of the seed crystal particles 121 can be in a high temperature environment (such as: melting The material does not react with hydrazine and does not decompose under the temperature at which the material is melted into a bismuth melt, and is not limited to the preferred material described above.

Furthermore, the seeding particles 121 are arranged in a layered manner on the bottom surface 111 of the crucible 110, and the seeding particles 121 are surrounded by the inner bottom surface 111 to define a Nucleation space 122.

It should be noted that, in this embodiment, the seed crystal particles 121 may be spherical and arranged in close proximity to each other. The seed crystal particles 121 can be arranged in the same manner as the misalignment shown in FIG. 2 or in a matrix arrangement as shown in FIG.

The diameters of the seed crystal particles 121 are substantially the same, and each of the seed crystal particles 121 has a diameter of approximately 0.5 mm to 40 mm. The density of the nucleation space 122 defined by the above-mentioned seed crystal particles 121 and the bottom surface 111 of the crucible 110 is not limited thereto, and is preferably 30% to 90%.

Moreover, when the seed crystal structure 120 (ie, the seeding particles 121) is disposed on the bottom surface 111 of the crucible 110, the distance D1 of the top edge of the ring side surface 112 of the crucible 110 from the inner bottom surface 111 is the top edge of the seed crystal structure 120. At least five times the distance D2 from the inner bottom surface 111. In more detail, the height D2 of the seed crystal structure 120 is preferably 15% or less of the height D1 of the ring side surface 112 of the crucible 110.

In other words, in the case where the above conditions are met, the seeding particles 121 are not limited to being arranged in one layer, and the seeding particles 121 may be arranged in two or more layers (as shown in FIG. 4). For example, if the seed crystal particles 121 are arranged in a layer, the diameter of the seed crystal particles 121 is preferably 15% or less of the height D1 of the ring side surface 112 of the crucible 110.

In addition, the seed crystal particles 121' may also be columnar (as in Figures 5 and 6) and arranged in a matrix at intervals to form a nucleation space 122' desired by the user. In practical applications, the preferred arrangement is matrix, but is not limited thereto.

In more detail, the seed crystal particles 121' are substantially identical square pillars, and the cross section of each seed crystal particle 121' (substantially parallel to the inner bottom surface 111) has a side length L of approximately 0.5 mm to 40. PCT. And, the above seeding particles 121' The nucleation space 122' defined by the inner bottom surface 111' preferably has a density of 30% to 90%.

In summary, the directional solidification device 100 can be used to solidify the sputum melt soup 200 (as shown in FIG. 9), and the seed crystal structure 120, 120 ′ can be used to inhibit the nucleation space 122, 122 ′ when the sputum melting soup 200 is solidified. The grain growth size of the inner melting soup 200. Thereby, the defect of the inside can be reduced by using the tantalum ingot 213 formed by the directional solidification apparatus 100 of the present embodiment.

[Second embodiment]

Referring to FIG. 7 to FIG. 14 , which is a second embodiment of the present invention, the difference between this embodiment and the first embodiment is mainly that the present embodiment mainly uses the seeding particles 121 of the first embodiment. Ingot manufacturing method.

Since the configuration described in the embodiment is substantially symmetrical, the configuration can be easily inferred from the first embodiment. Therefore, for convenience of explanation, the following description will be made in a sectional view. The steps of the method for producing a niobium ingot of the present embodiment are roughly as follows.

Step S101: As shown in FIG. 7, a crucible 110 is provided, and a specific number of seeding particles 121 are taken according to the area of the bottom surface 111 of the crucible 110. The specific number of the seed crystal particles 121 is preferably a number sufficient to arrange the seed crystal particles 121 in a layer shape, but is not limited thereto.

Step S102: As shown in FIG. 8, the seeding particles 121 are arranged in a layered manner on the bottom surface 111 of the crucible 110, and the seeding particles 121 are surrounded by the bottom surface 111 of the crucible 110 to define a Nuclear space 122.

The arrangement of the seed crystal particles 121 shown in FIG. 8 can be as shown in FIG. 2 and FIG. 3, but is not limited thereto.

Step S103: As shown in FIG. 9, a crucible (not shown) is placed thereon. The crucible 110 is heated and heated to melt the crucible to form a crucible 200.

Step S104: As shown in FIG. 10, the crucible soup 200 is solidified upward from the bottom surface 111 of the crucible 110. Among them, the crucible soup 200 located in the nucleation space 122 is restricted by the nucleation space 122, so that the size of grain growth is suppressed during solidification (that is, the growth of the initial large crystal grains is suppressed).

Step S105: As shown in FIG. 11, the crucible soup 200 is solidified to form a half finished product 210. The semi-finished product 210 is columnar and defines a cutting surface 211 substantially parallel to the bottom surface 111 of the crucible 110, and a portion of the semi-finished product 210 between the cutting surface 211 and the bottom surface 111 of the crucible 110 is defined as a template. The seeding structure 212, while the other portion of the semi-finished product 210 is defined as a tantalum ingot 213.

In more detail, the template seeding structure 212 includes the seeding particles 121 and a solid crucible 214 connecting the seeding particles 121.

Step S106: As shown in FIG. 12, the semi-finished product 210 is taken out and cut along its cutting surface 211 to form a tantalum ingot 213 and a template-type seeding structure 212. Thereby, the desired tantalum ingot 213 can be obtained, and the template seeding structure 212 can be used to replace the seeding particles 121 in the step S101, and then continue the subsequent steps to obtain another tantalum ingot (not shown) ).

Step S107: As shown in Fig. 13, another crucible 110' substantially the same as the crucible 110 described above is provided, and the template seeding structure 212 is placed on the bottom surface 111' of the other crucible 110'.

Step S108: As shown in FIG. 14, another crucible (not shown) substantially the same as the crucible is placed in another crucible 110', and heated to make another crucible and template The solid crucible 214 of the seeding structure 212 melts to form another crucible 200'.

Thereafter, by repeating steps S104 to S106, another tantalum ingot and another template seeding structure can be obtained. The other template-type seeding structure can be used continuously to repeat steps S106 to S108 described above, and then to step S104 to step S106.

Thereby, the ruthenium ingot 213 formed by the ruthenium ingot production method of the present embodiment can reduce the defects therein.

Further, as shown in FIG. 15, it is the case that the tantalum ingot 213 formed when the seed crystal grain 121 has a diameter of 1 mm is the same as the conventional tantalum ingot formed when the seed crystal structure is not used. A schematic diagram of the comparison of defect area density.

Here, A1 represents the wafer in the central region after the tantalum ingot 213 of the present embodiment is cut, and A2 represents the wafer in the side and corner regions after the tantalum ingot 213 of the present embodiment is cut. B1 represents a conventional crucible ingot in the central region after being cut, and B2 represents a conventional crucible ingot which is cut in the side and corner regions.

As is clear from Fig. 15, the defect ingot density of the tantalum ingot 213 formed in the present embodiment is remarkably improved as compared with the conventional one, and has an effect unpredictable by the conventional technique.

In addition, the ruthenium ingot 213 of this embodiment was subjected to dicing, and the crystal grains at the bottom thereof were tested to have a diameter of about 0.7 cm. However, the crystal grain size of the wafer of the conventional tantalum ingot after cutting is about 1.3 to 1.8 cm. That is to say, the carbide structure 120 of the directional solidification apparatus 100 of the present embodiment is used to suppress the size of grain growth of the crucible soup 200 located in the nucleation space 122 when the crucible soup 200 is solidified.

Furthermore, the template-type seeding structure 212 formed in the embodiment can effectively use the seeding particles 121 to be reused, thereby simplifying the processes of the above steps S101 and S102, thereby improving the production of the bismuth ingot 213. effectiveness The effect.

In addition, in the present embodiment, the spherical seeding particles 121 are described as being spherical, but in actual use, the seeding particles 121 are not limited to a spherical shape. In other words, the seed crystal particles 121 may also be columnar or irregular particles.

Furthermore, the tantalum melt used in the tantalum ingot 213 of the present invention may be polycrystalline germanium or single crystal germanium, that is, the tantalum ingot 213 may be formed of polycrystalline germanium grown or single crystal germanium grown. In other words, the crucible ingot 213 may be a solar ingot unit, a semiconductor ingot unit, or a sapphire ingot unit, which is not limited herein.

[Possible effects of the examples]

According to an embodiment of the present invention, a directional solidification device having the above-mentioned seed crystal particles and a method for manufacturing a ruthenium ingot using the above-mentioned seed crystal particles can all pass through a nucleation space to promote formation of a bismuth melt soup located in the nucleation space. The grain is used to reduce defects in the ingot casting.

Furthermore, the user can set the seeding particles by using the type of seed crystal particles or in different arrangement manners, so that the nucleation space forms a spatial pattern desired by the user.

In addition, after the first use, the seed crystal particles can be joined with the solid ruthenium to form a template-like seed crystal structure, so that the seed crystal particles can be effectively reused, and the pre-step of using the seed crystal particles is simplified, thereby achieving the lifting. The efficiency of the production efficiency of ingots.

The above description is only an embodiment of the present invention, and is not intended to limit the scope of the invention.

100‧‧‧Directional coagulation device

110, 110’‧‧‧ Shabu Shabu

111, 111'‧‧‧ inside bottom

112‧‧‧ ring side

120, 120'‧‧‧ seeding structure

121, 121'‧‧‧ seeding particles

122, 122’ ‧ ‧ nucleation space

200,200’‧‧‧矽 矽 molten soup

210‧‧‧Semi-finished products

211‧‧‧cut face

212‧‧‧Template-type seeding structure

213‧‧‧矽Ingots

214‧‧‧ Solid state

L‧‧‧ cross-section side length of seeding particles

D1‧‧‧Distance from the top edge of the side of the crucible ring from the inner bottom surface

D2‧‧‧Distance of the top edge of the seeding structure from the inner bottom surface

1 is a schematic cross-sectional view of a directional solidification apparatus according to a first embodiment of the present invention; FIG. 2 is a top plan view of FIG. 1; FIG. 3 is a top plan view of another arrangement of FIG. The seeding particles of the directional solidification device are arranged in a two-layer schematic view; FIG. 5 is a cross-sectional view showing another aspect of the seeding particles of the directional solidification device according to the first embodiment of the present invention; FIG. 5 is a schematic plan view of a step S101 of a method for manufacturing a bismuth ingot according to a second embodiment of the present invention; FIG. 8 is a schematic flow chart of a step S102 of a method for manufacturing a bismuth ingot according to a second embodiment of the present invention; FIG. 10 is a schematic flow chart of step S104 of the method for manufacturing the ingot casting ingot according to the second embodiment of the present invention; FIG. 11 is a schematic view showing the step S104 of the method for manufacturing the ingot casting ingot according to the second embodiment of the present invention; FIG. 12 is a schematic flow chart of step S106 of the method for manufacturing the ingot casting ingot according to the second embodiment of the present invention; and FIG. 13 is a flow chart of the step S107 of the method for manufacturing the ingot casting ingot according to the second embodiment of the present invention. Show FIG.; FIG. 14 A method of manufacturing a silicon ingot step S108 a second embodiment of the present invention. Schematic diagram of the process; and Figure 15 is a schematic view showing the defect area density of the tantalum ingot formed by the present invention compared to the conventional tantalum ingot.

100‧‧‧Directional coagulation device

110‧‧‧坩锅

111‧‧‧ inside bottom

112‧‧‧ ring side

120‧‧‧ seeding structure

121‧‧‧ seeding particles

122‧‧‧Nuclear space

D1‧‧‧Distance from the top edge of the side of the crucible ring from the inner bottom surface

D2‧‧‧Distance of the top edge of the seeding structure from the inner bottom surface

Claims (9)

A directional solidification device for solidifying a smelting soup, the directional solidification device comprising: a crucible comprising an inner bottom surface and a ring side surface connected to the inner bottom surface; and a seeding structure disposed in the crucible a distance from the inner bottom surface of the inner surface of the ring to the inner bottom surface is at least five times a distance from a top edge of the seed crystal structure from the inner bottom surface, wherein the seed crystal structure comprises a plurality of layers arranged in the crucible a seeding particle of the bottom surface, wherein the seeding particles are at least one of carbide particles, graphite particles and nitride particles, and the seeding particles and the inner bottom surface define a nucleation space for solidification When the soup is melted, the size of grain growth of the enamel soup located in the nucleation space can be suppressed. The directional solidification device according to claim 1, wherein the seed crystal particles are respectively spherical, and the seed crystal particles are arranged in close proximity to each other. The directional solidification apparatus according to claim 2, wherein the seed crystal particles have substantially the same diameter, and each of the seed crystal particles has a diameter of approximately 0.5 mm to 40 mm. The directional solidification device of claim 2, wherein the seed crystal particles are arranged in at least two layers. The directional solidification device according to claim 1, wherein the seed crystal particles are respectively columnar, and the seed crystal particles are arranged in a matrix at intervals. The directional solidification device according to claim 5, wherein the seed crystal particles are substantially identical square pillars, and each of the seed crystal particles is transverse. The length of the cross section is approximately 0.5 mm to 40 mm. A method for manufacturing a tantalum ingot using the seeding particles according to any one of claims 1 to 6, the method comprising the steps of: providing a crucible, and taking a specific area according to the area of the bottom surface of the crucible a number of seeding particles; the seeding particles are arranged in a layered manner on the bottom surface of the crucible, and the seeding particles are surrounded by the bottom surface of the crucible to define a nucleation space; The material is placed in the crucible, and heated to melt the crucible to form a crucible; the crucible is solidified from the bottom surface of the crucible, and the crucible located in the nucleation space passes through the crucible The limitation of the nuclear space is such that the size of the grain growth is inhibited during solidification; the enamel melt is solidified to form a semi-finished product, wherein the semi-finished product defines a cutting surface substantially parallel to the inner bottom surface of the crucible, and the semi-finished product a portion between the cutting surface and the bottom surface of the crucible is defined as a template-type seeding structure, the template-type seeding structure comprising the seeding particles and a solid crucible connecting the seeding particles, and the The other part of the semi-finished product is defined as a cast ingot And removing the semi-finished cutting along the cut surface of the silicon ingot to form the template type and seeding structure. The method for manufacturing a crucible ingot according to claim 7, wherein the method comprises: providing another crucible substantially the same as the crucible; placing the template-type seeding structure on the bottom surface of the other crucible And placing another crucible substantially identical to the crucible melt into the other crucible And heating to melt the other tantalum melt and the solid niobium of the template-type seed crystal structure to form another crucible. A template-type seeding structure is formed by the method of manufacturing a ruthenium ingot according to item 7 of the patent application.