A method for manufacturing a quartz crucible and a melting mold structure

Abstract

The invention discloses a quartz crucible manufacturing method and a melting mold structure. The method comprises the following steps: connecting an inner layer of a mold with a middle portion outside an outer layer of the mold to form two relatively independent cavities, and connecting the two cavities to vacuum systems respectively. After quartz sand is formed on the inner surface of the mold, a first vacuum system is turned on to evacuate the first cavity. After the first cavity reaches dynamic equilibrium, arc heating is turned on to allow ionized heat to be quickly brought to the corresponding inner surface of the first cavity portion along with airflow. After the corresponding quartz sand in the first cavity is quickly melted to seal the port, a second vacuum system is turned on to evacuate the second cavity. After the sealing layer is formed for a predetermined time, the first vacuum system and the second vacuum system are turned off to continue to melt the opaque layer of the crucible until a predetermined size is reached to form a prefabricated quartz crucible, so that microbubbles in the transparent layer are reduced, thereby improving the quality of the transparent layer, increasing the life of the crucible, and increasing the crystallization rate.

Description

Technical Field

[0001] The invention relates to the technical field of quartz crucible manufacturing, in particular to a quartz crucible manufacturing method and a melting mold structure. Background Art

[0002] With the development of the quartz crucible industry, especially the rapid development of the semiconductor industry, the requirements for quartz crucibles are getting higher and higher. The quartz crucibles used to pull silicon single crystals are now composed of two layers, an inner layer with low bubble content and an outer layer with high bubble density. For the inner layer, the lower the bubble or gas content, the better, without considering the influence of other factors.

[0003] In order to reduce the content of gas in the transparent layer, the solution of the prior art is to use a vacuum pump to extract the air in the quartz sand through the outer layer of the melting crucible and the melting mold during the crucible melting process. In the previous mold design, it is divided into an inner mold and an outer mold. The inner mold has a hole connecting the cavity and the quartz sand layer formed on the inner mold. There is a connecting cavity between the inner and outer molds. When vacuuming, it first acts on the cavity, and then the gas in the quartz sand is extracted through the hole.

[0004] Affected by mold cost, technical limitations, and efficiency. When vacuuming, the quartz sand being pumped is not a completely sealed structure. The gas enters the quartz sand at the mold port into the pumped cavity, and the vacuum degree cannot reach the limit value. There is residual gas in the melted crucible. This part of the gas gradually expands in the later stage of the crucible's use, forming large bubbles, which affects the life of the crucible. Summary of the invention

[0005] The object of the present invention is to provide a quartz crucible manufacturing method and a melting mold structure, so as to reduce the microbubble content in the fused quartz crucible and the amount of crucible gas dissolved, and improve the quality of the crucible.

[0006] In order to solve the above technical problems, an embodiment of the present invention provides a method for manufacturing a quartz crucible, comprising:

[0007] S1, after forming a quartz sand layer on the inner surface of the inner layer of the mold, start the first vacuum system, the area between the upper half of the inner layer of the mold and the outer layer of the mold is the first cavity, and the first cavity is vacuumed through a first through hole arranged in the outer layer of the mold;

[0008] S2, after the first cavity reaches dynamic equilibrium, start arc heating so that the ionized heat is quickly brought to the inner surface corresponding to the first cavity part along with the airflow;

[0009] S3, after the corresponding quartz sand in the first cavity is quickly melted to seal the port, the second vacuum system is turned on to evacuate the second cavity through the second through hole at the bottom of the outer layer of the mold, where the second cavity is the cavity between the lower half of the inner layer of the mold and the outer layer of the mold;

[0010] S4, after the quartz sand at the bottom and straight wall of the inner layer of the mold is melted to form a sealing layer for a predetermined period of time, the first vacuum system and the second vacuum system are closed, and the opaque layer of the crucible is continued to be melted until a predetermined size is reached to form a prefabricated quartz crucible.

[0011] Wherein, after S4, it also includes:

[0012] A portion of the quartz crucible corresponding to the first cavity is cut off.

[0013] In addition, an embodiment of the present application also provides a quartz crucible melting mold structure, including a mold inner layer and a mold outer layer, the mold outer layer is connected to the top periphery and the middle part of the mold inner layer, the mold outer layer is provided with a first through hole in the area between the top periphery and the middle part of the mold inner layer, and a second through hole is provided in the bottom area, the first through hole is connected to a first vacuum system and forms a first cavity with the mold outer layer and the mold inner layer, the second through hole is connected to a second vacuum system and forms a second cavity with the mold outer layer and the mold inner layer, the mold inner layer is connected to the first cavity and the second cavity through a third through hole and a countersunk hole, and the third through hole and the countersunk hole are filled with organized quartz sand through a mesh plug.

[0014] Wherein, it also includes a water cooling circulation loop device arranged on the outer wall of the outer layer of the mold.

[0015] The first through holes are spaced equally between the top peripheral connection and the middle connection of the mold outer layer and the mold inner layer.

[0016] Wherein, the distance between the middle connection point between the mold outer layer and the mold inner layer and the bottom of the mold inner layer is one half to two thirds of the height of the mold inner layer.

[0017] Wherein, the second through hole is located at the bottom center of the outer layer of the mold.

[0018] Wherein, the distance between the inner side wall of the outer layer of the mold and the outer side wall of the inner layer of the mold is equal everywhere.

[0019] The quartz crucible manufacturing method and melting mold structure provided by the embodiment of the present invention have the following advantages compared with the prior art:

[0020] The quartz crucible manufacturing method and the melting mold structure are described. The inner layer of the mold is connected to the middle part outside the outer layer of the mold to form two relatively independent cavities, and the two cavities are connected to the vacuum system respectively. After the quartz sand is formed on the inner surface of the inner layer of the mold, the first vacuum system is turned on to evacuate the first cavity; after the first cavity reaches dynamic equilibrium, the arc heating is turned on so that the ionized heat is quickly brought to the corresponding inner surface of the first cavity part along with the airflow; after the corresponding quartz sand in the first cavity is quickly melted to seal the port, the second vacuum system is turned on to evacuate the second cavity, and after the sealing layer is formed for a predetermined time, the first vacuum system and the second vacuum system are turned off, and the opaque layer of the crucible is continuously melted until it reaches a predetermined size to form a prefabricated quartz crucible, so that the microbubbles in the transparent layer are reduced, thereby improving the quality of the transparent layer, increasing the life of the crucible, and increasing the crystallization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 A schematic diagram of a process flow of an embodiment of a method for manufacturing a quartz crucible provided by an embodiment of the present invention;

[0023] Figure 2 A schematic structural diagram of an embodiment of a quartz crucible melting mold structure provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Please refer to Figure 1 , Figure 1 A schematic structural diagram of an embodiment of a high altitude rigid cable photovoltaic power generation system provided in an embodiment of the present invention.

[0026] In a specific embodiment, the method for making a quartz crucible comprises:

[0027] S1, after forming a quartz sand layer on the inner surface of the inner layer of the mold, start the first vacuum system, the area between the upper half of the inner layer of the mold and the outer layer of the mold is the first cavity, and the first cavity is vacuumed through a first through hole arranged in the outer layer of the mold;

[0028] S2, after the first cavity reaches dynamic equilibrium, start arc heating so that the ionized heat is quickly brought to the inner surface corresponding to the first cavity part along with the airflow;

[0029] S3, after the corresponding quartz sand in the first cavity is quickly melted to seal the port, the second vacuum system is turned on to evacuate the second cavity through the second through hole at the bottom of the outer layer of the mold, where the second cavity is the cavity between the lower half of the inner layer of the mold and the outer layer of the mold;

[0030] S4, after the quartz sand at the bottom and straight wall of the inner layer of the mold is melted to form a sealing layer for a predetermined period of time, the first vacuum system and the second vacuum system are closed, and the opaque layer of the crucible is continued to be melted until a predetermined size is reached to form a prefabricated quartz crucible.

[0031] By connecting the inner layer of the mold with the middle part outside the outer layer of the mold, two relatively independent cavities are formed, and the two cavities are connected to the vacuum system respectively. After the quartz sand is formed on the inner surface of the inner layer of the mold, the first vacuum system is turned on to evacuate the first cavity; after the first cavity reaches dynamic equilibrium, the arc heating is turned on so that the ionized heat is quickly brought to the corresponding inner surface of the first cavity part along with the airflow; after the corresponding quartz sand in the first cavity is quickly melted to seal the port, the second vacuum system is turned on to evacuate the second cavity, and after the sealing layer is formed for a predetermined time, the first vacuum system and the second vacuum system are turned off, and the opaque layer of the crucible is continued to be melted until it reaches a predetermined size to form a prefabricated quartz crucible, so that the microbubbles in the transparent layer are reduced, thereby improving the quality of the transparent layer, increasing the life of the crucible, and increasing the crystallization rate.

[0032] Since the portion corresponding to the first cavity may not meet the requirements, it needs to be removed. In one embodiment, after S4, the method further includes:

[0033] A portion of the quartz crucible corresponding to the first cavity is cut off.

[0034] In one embodiment, the method for making a quartz crucible is as follows: when in use, quartz sand is first formed on the inner surface of the mold, and the first vacuum system is first turned on to achieve dynamic balance. At this time, the vacuum pressure of the first cavity is less than 0.05 MPa. At this time, arc heating is turned on, and the ionized heat is quickly brought to the inner surface corresponding to part 2 in the figure along with the airflow. This part of the quartz sand quickly melts to form a sealing effect; after the corresponding port is sealed, the second vacuum system is turned on, and the gas is quickly dispersed at the bottom, and the quartz sand at the bottom and the straight wall is quickly melted to form a sealing layer. At this time, only the mold port cannot be closed, and the gas enters the quartz sand from here and is pumped away by the vacuum system. At this time, the pumping speed of the first vacuum system is increased. Since the port is melted first, the quartz sand layer is thin, and the gas is almost pumped away by the first vacuum system, and the second vacuum system is less affected. Therefore, the transparent layer of the crucible corresponding to the second vacuum system will be better; after the vacuum reaches the predicted time, the first and second vacuum systems are turned off, and the opaque layer of the crucible continues to be melted until it reaches the predetermined size; after the melting is completed, the part corresponding to the first vacuum system is cut off, and a crucible with a lower bubble density in the transparent layer corresponding to the second vacuum system can be obtained. When the customer uses the same one, the transparent layer of the crucible can still be guaranteed, and the use time can be delayed.

[0035] In addition, an embodiment of the present application also provides a quartz crucible melting mold structure, including a mold inner layer 1 and a mold outer layer, the mold outer layer is connected to the top periphery and the middle part of the mold inner layer 1, the mold outer layer is provided with a first through hole in the area between the top periphery and the middle part of the mold inner layer 1, and a second through hole is provided in the bottom area, the first through hole is connected to a first vacuum system and forms a first cavity 2 with the mold outer layer and the mold inner layer 1, the second through hole is connected to a second vacuum system and forms a second cavity 3 with the mold outer layer and the mold inner layer 1, the mold inner layer 1 is connected to the first cavity 2 and the second cavity 3 through a third through hole and a countersunk hole, and the third through hole and the countersunk hole are filled with organized quartz sand through a mesh plug.

[0036] Since the quartz crucible melting mold structure is a structure corresponding to the above-mentioned quartz crucible manufacturing method and has the same beneficial effects, this application will not elaborate on it.

[0037] In order to further improve the production efficiency, in one embodiment, the quartz crucible melting mold structure further includes a water cooling circulation loop device arranged on the outer wall of the outer layer of the mold.

[0038] By providing a water cooling circulation loop device, on the one hand, rapid cooling of the crucible can be achieved, and on the other hand, the temperature at various locations can be balanced to improve the quality of the crucible.

[0039] The present application does not limit the specific position of the first through hole. Generally, in order to achieve vacuum balance, in one embodiment, the first through hole is spaced equally between the top peripheral connection and the middle connection of the mold outer layer and the mold inner layer 1.

[0040] The size, shape and specific position of each through hole are not limited in this application.

[0041] The present application does not limit the connection position between the mold outer layer and the mold inner layer 1. Generally, the distance between the middle connection between the mold outer layer and the mold inner layer 1 and the bottom of the mold inner layer 1 is one half to two thirds of the height of the mold inner layer 1.

[0042] Preferably, the second through hole is located at the bottom center of the mold outer layer.

[0043] In order to improve the manufacturing efficiency of the crucible and the balance at all locations, in one embodiment, the distance between the inner side wall of the mold outer layer and the outer side wall of the mold inner layer 1 is equal at all locations.

[0044] In this application, the vacuum system is separated, and the defects of the original system are circumvented by one system; the vacuum system at the target position is made to meet higher requirements; different opening sequences can be formulated to reduce the impact caused by the defect that the port cannot be closed.

[0045] The first cavity 2 in the present application is connected to the vacuum pump of the first vacuum system through a plurality of pipes 4, and the gas in the first cavity is evacuated through the vacuum pump.

[0046] In summary, the quartz crucible manufacturing method and melting mold structure provided in the embodiment of the present application connect the inner layer of the mold with the middle part outside the outer layer of the mold to form two relatively independent cavities, and connect them to the vacuum system respectively. After the quartz sand is formed on the inner surface of the inner layer of the mold, the first vacuum system is turned on to evacuate the first cavity; after the first cavity reaches dynamic equilibrium, the arc heating is turned on so that the ionized heat is quickly brought to the corresponding inner surface of the first cavity part along with the airflow; after the corresponding quartz sand in the first cavity is quickly melted to seal the port, the second vacuum system is turned on to evacuate the second cavity, and after the sealing layer is formed for a predetermined period of time, the first vacuum system and the second vacuum system are turned off, and the opaque layer of the crucible is continued to be melted until it reaches a predetermined size to form a prefabricated quartz crucible, so that the microbubbles in the transparent layer are reduced, thereby improving the quality of the transparent layer, increasing the life of the crucible, and improving the crystallization rate.

[0047] The above is a detailed introduction to the quartz crucible manufacturing method and the melting mold structure provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A quartz crucible melting mold structure, characterized in that: The mold comprises a mold inner layer and a mold outer layer, wherein the mold outer layer is connected to the top periphery and the middle part of the mold inner layer, the mold outer layer is provided with a first through hole in the area between the top periphery and the middle part of the mold inner layer, and a second through hole is provided in the bottom area, the first through hole is connected to a first vacuum system and forms a first cavity with the mold outer layer and the mold inner layer, the second through hole is connected to a second vacuum system and forms a second cavity with the mold outer layer and the mold inner layer, the mold inner layer is connected to the first cavity and the second cavity through a third through hole and a countersunk hole, the third through hole and the countersunk hole are filled with a mesh plug to prevent quartz sand from passing through, and also comprises a water-cooling circulation loop device arranged on the outer wall of the mold outer layer, the first through hole is equidistant between the top periphery connection and the middle connection of the mold outer layer and the mold inner layer.

2. The quartz crucible melting mold structure according to claim 1, characterized in that: The distance between the middle connection point between the mold outer layer and the mold inner layer and the bottom of the mold inner layer is one half to two thirds of the height of the mold inner layer.

3. The quartz crucible melting mold structure according to claim 2, characterized in that: The second through hole is located at the bottom center of the mold outer layer.

4. The quartz crucible melting mold structure according to claim 3, characterized in that: The distance between the inner side wall of the outer layer of the mold and the outer side wall of the inner layer of the mold is equal everywhere.

5. A method for making a quartz crucible, characterized in that: The quartz crucible mold structure according to any one of claims 1 to 4 is adopted, comprising: S1, after forming a quartz sand layer on the inner surface of the inner layer of the mold, start the first vacuum system, the area between the upper half of the inner layer of the mold and the outer layer of the mold is the first cavity, and the first cavity is vacuumed through a first through hole arranged in the outer layer of the mold; S2, after the first cavity reaches dynamic equilibrium, start arc heating so that the ionized heat is quickly brought to the inner surface corresponding to the first cavity part along with the airflow; S3, after the corresponding quartz sand in the first cavity is quickly melted to seal the port, the second vacuum system is turned on to evacuate the second cavity through the second through hole at the bottom of the outer layer of the mold, where the second cavity is the cavity between the lower half of the inner layer of the mold and the outer layer of the mold; S4, after the quartz sand at the bottom and the straight wall of the inner layer of the mold is melted to form a sealing layer for a predetermined time, the first vacuum system and the second vacuum system are closed, and the opaque layer of the crucible is continued to be melted until a predetermined size is reached to form a prefabricated quartz crucible. After S4, the method further includes: A portion of the quartz crucible corresponding to the first cavity is cut off.

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