The invention relates to semiconductor manufacturing equipment and a manufacturing method thereof, in particular to a graphite crucible and a manufacturing method thereof.
Background technique
The pulling method is a method of synthesizing crystals invented by ( ) in 1917, so it is also called the "method", which is a method of growing crystals from molten raw materials. The principle of the pulling method is to use temperature field control to make the molten raw material grow into crystals. The crystal growth raw material is heated in the crucible to form a melt, and the temperature distribution (temperature field) in the growth furnace is controlled so that the temperature of the melt and the seed/crystal have a certain temperature gradient. At this time, after the seed crystal is in contact with the melt, the surface melts, the seed rod is pulled and rotated, and the supercooled melt crystallizes on the seed, and with the process of pulling and rotating, the seed crystal and the melt The atoms or molecules in the crystal are constantly rearranged on the interface, and gradually solidify to grow a single crystal.
A quartz crucible is a general-purpose device used to hold molten reactive materials. However, quartz crucibles will soften and deform at high temperatures. Therefore, it is very important to choose a material that can support the quartz crucible to maintain its original shape.
Because graphite has good heat resistance and thermal shock resistance, especially good chemical stability, graphite is widely used in the field of crucibles. The equipment structure of quartz crucible 201 and graphite crucible 202 for single crystal silicon pulling is shown in Figure 1. The single crystal silicon growth raw material is placed in the quartz crucible and heated by heater 205 to form melt 204, which is controlled in the growth furnace. The temperature distribution (temperature field) makes the temperature of the melt 204 and the seed/crystal 205 have a certain temperature gradient. At this time, the surface of the seed crystal 203 on the seed crystal rod is in contact with the melt 204 to melt, pull and rotate the seed crystal rod, and the supercooled melt will crystallize on the seed crystal, and along with the process of pulling and rotating, the seed crystal and The interface between the melts constantly rearranges atoms or molecules and gradually solidifies. Growing monocrystalline silicon ingots.
However, due to the larger diameter of the stretched silicon wafer, the thermal expansion mismatch effect between the quartz crucible and the graphite crucible is more serious. This mismatch effect makes the support function of the graphite crucible unable to fully meet the application requirements.
Based on the above, it is necessary to provide a method and structure that can effectively improve the large deformation of the graphite crucible due to the large expansion coefficient.
Technical realization elements:
Given the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a graphite crucible and a manufacturing method thereof, which are used to solve the problem of overfitting the graphite crucible and the quartz crucible. prior art due to its high coefficient of expansion. Prone to problems such as cracks.
For realizing the above-mentioned purpose and another relevant purpose, the present invention provides a kind of manufacturing method for graphite crucible, and this manufacturing method comprises: 1) provide crucible mold; Adhesive, covering the silicon nitride fiber mesh on the adhesive; 3) Repeat step 2), the number of repetitions is n, wherein, n>0; 4) After the adhesive is cured, the mold is molded to obtain a crucible template; 5) carbonizing and graphitizing the crucible template to obtain a graphite crucible.
Preferably, step 2) providing the silicon nitride fiber web includes: a) mixing with pyridine in proportion and then poly ammonolysis to obtain perhydropolysilazane resin (phs); b) making perhydropolysilazane resin (phs) Dissolving in the organic solvent xylene to obtain a spinning stock solution; c) filtering the spinning stock solution, and obtaining perhydropolysilazane fibers after dry spinning; d) subjecting the spinning stock solution to ammonia pyrolysis and perhydropolysilazane Sintering the alkane fibers to obtain silicon nitride fibers; e) Laying the silicon nitride fibers into a network to obtain a silicon nitride fiber network.
Preferably, in step a), the molar ratio of said substance to pyridine is 1:1 to 1:3.
Preferably, the temperature range of the polymerization reaction in step a) is 80-220° C., the atmosphere of the ammonolysis reaction is an ammonia atmosphere, and the temperature is room temperature.
Preferably, the crucible mold includes a mold body and a mold bottom, and step 2) includes: 2-1) providing a first silicon nitride fiber web, coating a binder containing graphite raw materials in the mold, and the first silicon nitride fiber net is placed on the binder; 2-2) the second silicon nitride fiber net is provided, and the binder containing graphite raw material is coated at the bottom of the mold, and the second silicon nitride fiber net is laid on the binder above; wherein the length of the silicon nitride fibers in the second silicon nitride fiber web is shorter than the length of the silicon nitride fibers in the first silicon nitride fiber web.
Preferably, the binder containing graphite raw material is a mixture of graphite powder and resin material.
Preferably, the silicon nitride fibers in the silicon nitride fiber network have a diameter ranging from 4-20 μm.
Preferably, the silicon nitride fiber net includes a plurality of first-direction silicon nitride fibers arranged in parallel along the first direction and a plurality of second-direction silicon nitride fibers arranged in parallel along the second direction, the first direction and the second direction The angle θ between the two directions and the second direction is 90°≤θ<180°.
Preferably, the mesh size of the silicon nitride fiber net is in the range of 0.1-2 mm.
Preferably, step 3) repeats step 2) 4-10 times, and the silicon nitride fiber nets are arranged in parallel.
The present invention also provides a graphite crucible, wherein at least one layer of silicon nitride fiber net is arranged in the graphite crucible, the silicon nitride fiber net completely covers the entire range of the graphite crucible, and the silicon nitride fiber net is closely combined with the graphite-graphite crucible material.
Preferably, the graphite crucible includes a crucible body and a crucible bottom, and the silicon nitride fiber mesh includes a first silicon nitride fiber mesh arranged in the crucible body and a second nitrogen mesh arranged in the crucible bottom. A silicon nitride fiber web, wherein the length of the silicon nitride fibers in the second silicon nitride fiber web is shorter than the length of the silicon nitride fibers in the first silicon nitride fiber web.
Preferably, the silicon nitride fibers in the silicon nitride fiber network have a diameter ranging from 4-20 μm.
Preferably, the silicon nitride fiber net includes a plurality of first-direction silicon nitride fibers arranged in parallel along the first direction and a plurality of second-direction silicon nitride fibers arranged in parallel along the second direction, the first direction and the second direction The angle θ between the two directions and the second direction is 90°≤θ<180°.
Preferably, the mesh size of the silicon nitride fiber net is in the range of 0.1-2mm.
Preferably, the number of layers of the silicon nitride fiber web is 4 to 10 layers, and the silicon nitride fiber web is arranged in parallel.
In summary, the graphite crucible of the present invention and its manufacturing method have the following beneficial effects: the present invention prepares continuous silicon nitride fibers through a dry spinning process, and the silicon nitride fibers have a low expansion coefficient, good thermal conductivity, and superior performance. Mechanical properties and other advantages; By setting one or more layers of continuous silicon nitride fiber nets arranged in parallel in the wall of the graphite crucible to form a continuous fiber reinforcement layer, the deformation of the graphite crucible due to thermal expansion and cooling can be greatly reduced, avoiding graphite The crucible develops cracks and improves its compatibility with quartz crucibles. The invention can effectively improve the quality of the graphite crucible and has broad application prospects in the field of semiconductor equipment and manufacturing.
Drawing Description
Fig. 1 is a schematic diagram of the equipment structure of a graphite crucible and a quartz crucible for pulling single crystal silicon in the prior art.
Fig. 2 is a schematic flow chart of the steps of the graphite crucible manufacturing method of the present invention.
Fig. 3 is a schematic diagram of silicon nitride fibers in the graphite crucible manufacturing method of the present invention.
Fig. 4 is a schematic structural diagram of dry spinning equipment in the graphite crucible manufacturing method of the present invention.
5 to 6 are structural schematic diagrams of silicon nitride fiber webs in the method for manufacturing a graphite crucible according to the present invention.
Fig. 7 is a schematic structural view of the silicon nitride fiber mesh reinforced graphite crucible of the present invention.
Description of the component name
10 silicon nitride fiber mesh
101 silicon nitride fiber
301 material tank
302 gear metering pump
303 spinneret
304 spinning tunnel
305 hot air
306 feeding tray
307 guide hook
308 twisting mechanism
309 air outlet
40 graphite crucible
401 crucible body
402 crucible bottom
501 silicon nitride fiber mesh
502 ethylene dinitride fiber mesh
detailed method
The implementation of the present invention will be described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes. Without departing from the spirit of the present invention, various modifications or changes can be made to the details in this specification based on different viewpoints and applications.
Please refer to Figure 2 to Figure 7. It should be noted that the schematic diagram provided in this embodiment only schematically illustrates the basic idea of the present invention, so only parts related to the present invention are shown in the figure, rather than compared with the quantity, shape, and dimension diagram, The type, quantity and ratio of each component can be changed arbitrarily during actual implementation, and the type of component layout may also be more complicated.
As shown in Fig. 2 to Fig. 7, the present embodiment provides a kind of manufacturing method for graphite crucible 40, and this manufacturing method comprises:
Referring to Fig. 2 as shown in the figure, first, perform step 1) s11 to provide a crucible mold.
For example, crucible molds are made of materials with certain rigidity and high-temperature resistance. Its material can be metal, such as stainless steel, etc., and the inner wall is smooth, which is beneficial to the subsequent grinding of the crucible template and the crucible mold. The quality of the template.
The crucible mold includes a mold body and a mold bottom. The side wall of the mold body is cylindrical, and the mold bottom is arc-shaped bottom to match the shape of the subsequent quartz crucible.
As shown in Fig. 2 to Fig. 7, carry out step 2) s12 then, provide silicon nitride () fiber web, in crucible mold, be coated with the binding agent that contains graphite raw material, silicon nitride fiber web 10 is covered on bonding On the dose.
For example, the crucible mold includes a mold body and a mold bottom, and step 2) includes:
2-1) Provide the first silicon nitride fiber net 501, coat the binder containing graphite raw material in the mold body, and cover the first silicon nitride fiber net 501 on the binder;
2-2) The second silicon nitride fiber net 502 is provided, and the binder containing graphite raw material is coated on the bottom of the mold, and the second silicon nitride fiber net 502 is covered on the binder; wherein, the second silicon nitride The length of the silicon nitride fibers 101 in the fiber web 502 is smaller than the length of the silicon nitride fibers 101 in the first silicon nitride fiber web 501.
Since the main body of the mold is usually designed as a cylinder and the bottom of the mold is usually designed as a curved surface, by designing two parts of silicon nitride fiber mesh 10 with different lengths, the entire crucible mold can be covered more completely, continuously, and the graphite can be greatly strengthened. The mechanical strength of the crucible 40 restrains its degree of deformation.
As an example, the binder containing graphite raw material is a mixture of graphite powder and resin material. The mixture forms the main body of the graphite crucible 40 after subsequent carbonization and graphitization.
For example, the diameter range of the silicon nitride fiber 101 in the silicon nitride fiber net 10 is 4-20 μ m, the silicon nitride fiber 101 in this diameter range can be realized by dry spinning process, which can guarantee the silicon nitride fiber 101 strength. In this embodiment, the silicon nitride fiber 101 has a diameter of 10 μm.
As shown in Figure 5 and Figure 6, as an example, the silicon nitride fiber net 10 includes a plurality of silicon nitride fibers 101 arranged in parallel along a first direction and a plurality of second silicon nitride fibers 101 arranged in parallel in a second direction. For the oriented silicon nitride fiber 101, the angle θ between the first direction and the second direction is 90°≦θ<180°. The included angle between the first direction and the second direction is preferably 90°≤θ≤120° and the mesh size range of the silicon nitride fiber web 10 is 0.1-2 mm so that a higher strength silicon nitride fiber web 10 can be obtained. As shown in the picture. FIG. 5 is a schematic structural diagram of a silicon nitride fiber net 10 with θ=90°, and the mesh parameters d1 and d2 range from 0.1 to 2 mm. As shown in the picture. FIG. 6 is a schematic structural diagram of a silicon nitride fiber net 10 with θ=120°, and the value range of grid parameters d3 and d4 is 0.1-2 mm.
As shown in Figures 3 to 4, the silicon nitride fiber web 10 provided in step 2) includes:
First, carry out step a) s21, after mixing with pyridine in proportion, carry out polymerization reaction and ammonolysis reaction, obtain perhydropolysilazane resin (phs);
As an example, in step a), the amount (molar) ratio of the substance to pyridine is from 1:1 to 1:3. In this example, the molar ratio of the substance to pyridine is 1:2.
For example, the said and pyridine is mixed using mechanical agitation to obtain a homogeneous mixture.
As an example, the temperature range of the polymerization reaction in step a) is 80-220°C, specifically 100°C, 150°C, etc., the atmosphere of the ammonolysis reaction is an ammonia atmosphere, and the temperature is room temperature.
Then proceed to step b) s22, dissolving the perhydropolysilazane resin (phs) in an organic solvent to obtain a spinning dope.
For example, xylene is selected as the organic solvent, and perhydropolysilazane resin (PHS) is stirred evenly with xylene.
Then proceed to step c) s23, filter the spinning dope and obtain perhydropolysilazane fibers after dry spinning.
For example, the method used for filtration is physical filtration, that is, the spinning dope is filtered through an intermediate filter matrix composed of a nylon fabric protective layer and filter paper.
This example uses dry spinning to form perhydropolysilazane fibers. The dry spinning equipment used in this embodiment is shown in Figure 4, including a trough 301, a gear metering pump 302, a spinneret 303, a spinning channel 304, a feeding disc 306, a guide hook 307, and a twisting and winding mechanism 308. After the spinning stock solution is sent into trough 301, it first passes through the gear metering pump 302. The gear metering pump 302 passes through a pair of intermeshing gears, one of which is a driving gear and the other is a driving gear. Is the driven gear, driven by the driving gear? The meshing rotation leaves a small gap directly between the gear and the pump casing. When the gear rotates, the closed volume between the teeth increases in the suction chamber where the gear teeth gradually disengage, forming a partial vacuum. When rotating, the spinning dope is divided into two paths between the gear and the casing, pushed forward by the gear, and sent to the liquid discharge chamber. In the discharge chamber, the two gears mesh gradually, the volume decreases, and the liquid between the gears is squeezed into the spinneret. 303. By measuring the rotational speed of the gear metering pump, the flow rate of the gear metering pump can be obtained. Then, the spinneret 303 spins the spinning shaft 304, the hot air 305 enters the spinning shaft 304, evaporates the organic solvent in the spinning stock solution, and carries it to the air outlet 309 to discharge, and the spinneret 303 sprays the finished product The yarn is sent to the twisting and winding mechanism 308 through the yarn feeding disc 306 and the guide hook 307, where the twisting and winding operation is performed to obtain perhydropolysilazane fibers.
Then step d) s24 is performed, and the perhydropolysilazane fibers are subjected to ammonia pyrolysis and sintering to obtain silicon nitride fibers 101.
For example, the ammonia pyrolysis atmosphere is an ammonia gas atmosphere, and the temperature ranges from 1100°C to 1300°C, specifically 1200°C.
For example, the sintering atmosphere is a high-purity nitrogen atmosphere, and the temperature ranges from 1400°C to 1600°C, specifically 1500°C.
Step e) s25, laying the silicon nitride fiber 101 into a web to obtain a silicon nitride fiber web 10.
As shown in Figure 2, perform step 3) s13, repeat step 2), the number of repetitions is n, wherein, n>0;
As an example, step 3) repeats step 2) 4-10 times, and the silicon nitride fiber webs 10 are arranged in parallel. A graphite crucible 40 with higher mechanical strength can be obtained by repeatedly arranging a plurality of silicon nitride fiber webs 10 arranged in parallel.
Referring to Fig. 2 as shown in the figure, proceed to step 4) s14, after the glue is cured, de-mold to obtain the crucible template.
As shown in Fig. 2 and Fig. Referring to FIG. 7, step 5) s15 is finally performed to carbonize and graphitize the crucible template to obtain a graphite crucible 40.
As shown in Figure 7, the present embodiment also provides a graphite crucible 40, wherein at least one layer of silicon nitride fiber mesh 10 is provided, the silicon nitride fiber mesh 10 completely covers the entire range of the graphite crucible 40, and the silicon nitride fiber mesh The mesh 10 is closely bonded to the graphite material of the graphite crucible 40. Wherein, FIG. 7 only shows the arrangement form of the silicon nitride fiber net 10, and does not show the graphite material, but its shape corresponds to that of the silicon nitride fiber net 10 in FIG. 3 . 7.
As an example, the graphite crucible 40 includes a crucible body 401 and a crucible bottom 402, and the silicon nitride fiber mesh 10 includes the first silicon nitride fiber mesh 501 arranged in the crucible body 401 and a first silicon nitride fiber mesh arranged in the crucible body 401. Fiber web 501. Crucible body 401. The second silicon nitride fiber web 502 in the bottom 402 of the crucible, wherein the length of the silicon nitride fiber 101 in the second silicon nitride fiber web 502 is shorter than the length of the first silicon nitride fiber web 101. The silicon nitride fiber web 501 is the length of the silicon fiber 101.
As an example, the silicon nitride fiber 101 in the silicon nitride fiber mesh 10 has a diameter in the range of 4-20 μm.
As an example, the silicon nitride fiber net 10 includes a plurality of silicon nitride fibers 101 arranged in parallel in the first direction and a plurality of silicon nitride fibers 101 arranged in parallel in the second direction in the second direction. The included angle θ between the first direction and the second direction is 90°≤θ<180°.
As an example, the silicon nitride web 10 has a mesh size ranging from 0.1 to 2 mm.
As an example, the number of layers of the silicon nitride fiber web 10 is 4-10 layers, and the silicon nitride fiber web 10 is arranged in parallel.
In summary, the graphite crucible 40 of the present invention and its manufacturing method have the following beneficial effects: the present invention prepares continuous silicon nitride fibers 101 through a dry spinning process, the expansion coefficient of the silicon nitride fibers 101 is low, and the performance Good thermal conductivity, superior mechanical properties, etc.; By setting one or more parallel continuous silicon nitride fiber webs 10 on the wall of the graphite crucible 40 to form a continuous fiber reinforcement layer, the thermal expansion of the graphite crucible 40 can be greatly reduced. And the degree of deformation during the cooling process, avoiding cracks in the graphite crucible 40, and improving the matching degree with the quartz crucible. The invention can effectively improve the quality of the graphite crucible 40 and has broad application prospects in the field of semiconductor equipment and manufacturing.
Therefore, the present invention effectively overcomes various deficiencies in the prior art and has high industrial application value.
The above-mentioned embodiments are only for illustrating the principles and functions of the present invention and are not intended to limit the present invention. Those skilled in the art may make modifications or changes to the above-described embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention shall still be protected by the claims of the present invention.
Technical Features:
Technical overview
The invention provides a graphite crucible and a manufacturing method thereof. The manufacturing method includes: 1) providing a crucible mold; 2) providing a silicon nitride fiber net, coating a binder containing graphite raw materials in the crucible mold, and laying the silicon nitride fiber net on the binder; 3) repeating the steps 2), the number of repetitions is N, wherein, N>0; 4) After the binder is solidified, the mold is demolded to obtain a crucible template; 5) The crucible template is carbonized and graphitized to obtain a graphite crucible. The invention adopts dry spinning to prepare continuous silicon nitride fibers, which have the advantages of low expansion coefficient, good thermal conductivity, and superior mechanical properties; by setting one or more parallel continuous silicon nitride fibers in the graphite crucible wall, The silicon fiber mesh forms a continuous fiber reinforced layer, which can greatly reduce the deformation of the graphite crucible due to thermal expansion and cooling process, and avoid cracks in the graphite crucible.
Technical research and development personnel: Wang Yan