Patent Application
20180312997
This application claims the priority benefit of Taiwan application serial no. 106114197, filed on Apr. 28, 2017. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
The invention is related to a crucible structure and a manufacturing method thereof as well as a silicon crystal structure and a manufacturing method thereof, and particularly to a crucible structure for manufacturing a silicon crystal structure and a manufacturing method thereof as well as a silicon crystal structure using the crucible structure and a manufacturing method thereof.
Currently the manufacturing method of multi-ingot is carried in the following sequence: filling a quartz crucible with a silicon material; subsequently, the silicon material is heated to be melted into a molten silicon material; afterwards, the molten silicon material is cooled and solidified to form multi-ingot; finally, the quartz crucible is removed. In order to separate the multi-ingot from the quartz crucible, typically a layer of silicon nitride is sprayed on the surface of quartz crucible as a releasing agent to avoid that the silicon material is adhered to the quartz crucible after reaction. In the cooling process, since the ratio of cooling and contraction for silicon ingot is different from that of the quartz crucible, pulling is occurred and crystal ingot is subsequently cracked. However, the adhesion between the silicon nitride powder is not strong, in the crystal-growing process, there is a high chance that a part of the silicon nitride powder falls into the crystal ingot and forms defect derived from impurities. In addition, since the silicon nitride is expensive, the high cost causes problems if silicon nitride is used as the coating layer for quartz crucible.
Moreover, in the current manufacturing method of single ingot, when the quartz crucible and silicon material are heated, the crucible gradually generates cristobalite having a loose structure. In order to generate cristobalite with higher density, a little amount of barium compound (e.g., between 0.6×10−4 g/cm2 and 0.9×10−4 g/cm2) is coated on the surface of inner wall of the crucible, thereby forming a little amount of barium silicate to facilitate formation of a cristobalite discontinuous film having a thickness of not greater than 30 μm so as to prevent reaction between the silicon material and crucible, instead of being used as a releasing agent. Furthermore, in the process of forming single crystal, since a pulling method is used, the single crystal structure is not in direct contact with the quartz crucible.
The invention provides a crucible structure which may reduce the manufacturing cost.
The invention further provides a manufacturing method of a crucible structure for manufacturing the crucible structure.
The invention further provides a manufacturing method of a silicon crystal structure via the crucible structure, which may lower the manufacturing cost and effectively reduce or avoid the probability that the impurity falls into the silicon crystal structure.
The invention further provides a silicon crystal structure which is grown via the crucible structure.
The crucible structure of the invention is adaptable for manufacturing a silicon crystal structure. The crucible structure comprises a crucible body and a release coating layer. The material of the crucible body comprises silicon dioxide. The release coating layer directly covers the crucible body, and the material of the release coating layer comprises barium silicate. The barium silicate is a continuous film for contacting the silicon crystal structure, and the thickness of the release coating layer is between 35 μm and 350 μm.
In the manufacturing method of crucible structure of the invention, the crucible structure is adaptable for manufacturing a silicon crystal structure. The manufacturing method of the crucible structure comprises the following steps: providing a crucible body, wherein the material of the crucible body comprises silicon dioxide; coating a raw material of release coating layer containing a barium compound material on the crucible body; heating the crucible body and the raw material of release coating layer to form a release coating layer that directly covers the crucible body; the material of the release coating layer comprises barium silicate, and the barium silicate is a continuous film for contacting the silicon crystal structure, wherein the thickness of the release coating layer is between 35 μm and 350 μm.
In the invention, the manufacturing method of a silicon crystal structure comprises the following steps: providing a crucible body, wherein the material of the crucible body comprises silicon dioxide; coating a raw material of release coating layer containing a barium compound material on the crucible body; filling the crucible body with a silicon material, wherein the raw material of release coating layer is disposed between the crucible body and the silicon material; heating the crucible body, the raw material of release coating layer and the silicon material to a first temperature to form a release coating layer that directly covers the crucible body; the material of the release coating layer comprises barium silicate, and the barium silicate is a continuous film for contacting the silicon crystal structure, wherein the thickness of the release coating layer is between 35 μm and 350 μm; heating the crucible body, the release coating layer and the silicon material from a first temperature to a second temperature so that the silicon material is formed into a molten silicon material; cooling the crucible body so that the molten silicon material is formed into a silicon crystal structure that is directly in contact with the crucible body.
In the invention, the silicon crystal structure is grown via the crucible structure.
Based on the above, the crucible structure of the invention uses the release coating layer that contains barium silicate as the material to replace conventional purity silicon nitride layer, wherein the barium silicate is a continuous film for contacting the silicon crystal structure, and the thickness of the release coating layer is between 35 μm and 350 μm. As compared with the spraying cost of conventional crucible, the release coating layer used for the crucible structure of the invention not only can effectively lower the manufacturing cost, but also can effectively reduce or avoid the probability that impurity falls into the silicon crystal structure formed in the subsequent process.
In addition, in the manufacturing method of the silicon crystal structure of the invention, the formation of the release coating layer and silicon crystal structure are combined as a single batch reaction. That is, the raw material of release coating layer is reacted with the crucible body first to form the release coating layer (which comprises barium silicate as the material) that directly covers the crucible body, and the silicon crystal structure is formed afterwards. The above method can avoid the problem that high temperature causes the crucible body to be softened while ensuring completeness of reaction of the release coating layer. Accordingly, the cost required for performing spraying on the crucible body can be decreased, and the probability that impurity falls into the silicon crystal structure can be effectively reduced or avoided.
In order to make the aforementioned features and advantages of the invention more comprehensible, embodiments accompanying figures are described in detail below.
Specifically, the crucible structure 100 in the embodiment is adapted for manufacturing a silicon crystal structure (not shown) such as multi-ingot, quasi-single crystal ingot or casted single ingot. The material of the crucible body 110 includes silicon dioxide. In other words, the crucible body 110 may be pure silicon dioxide crucible, also known as quartz crucible. Alternatively, the inner layer of the crucible body 110 is silicon dioxide, and the outer layer of the crucible body 110 is graphite, silicon carbide or other materials. The crucible body 110 has a bottom surface 112 and a plurality of side surfaces 114 which are connected to the bottom surface 112. Herein, the crucible body 110 is formed by hot-pressing quartz sand. As compared with silicon dioxide crucible that is formed by casting dissolved quartz sand for pulling the single crystal structure, the above crucible body has a relatively loose structure (or porosity is relatively high), and the surface thereof is rougher. Alternatively, the inner wall of the crucible body 110 has a center-line average roughness value (Ra) between 5 μm and 35 μm. In this manner, the material of the release coating layer 120 has a better adhesion to the surface of the crucible body 110 with more amount and lower cost.
Further referring to
It should be pointed out that, in the embodiment, if the release coating layer 120 is formed by directly reacting the barium carbonate as the reactant with silicon dioxide (i.e. the material of crucible body 110), then the amount of barium carbonate to be coated is, for example, 1.35×10−4 g/mm2. In other embodiments, the amount of barium compound material may be between 0.3×10−2 g/cm2 and 5×10−2 g/cm2, thereby directly forming the continuous barium silicate film instead of a continuous cristobalite film. In addition, since the crucible structure 100A is relatively loose, it is relatively difficult for the cristobalite to be generated. Even if a little amount of cristobalite is generated, a continuous cristobalite film is unlikely to be formed.
It should be indicated that the following embodiments use the reference numerals and a part of the descriptions mentioned in the previous embodiments, wherein the same reference numbers are used to denote identical or similar elements. Meanwhile, the same technical content is omitted. Please refer to the previous embodiments for the omitted descriptions; no repetitions are incorporated into the following embodiments.
It should be mentioned that, in other embodiments, the release coating layer 120 may further contain silicon nitride, wherein the ratio of the barium silicate to silicon nitride is between 10:90 and 99:1. Herein, the barium silicate can secure the silicon nitride to avoid the silicon nitride from peeling off. Referring to
Thereafter, referring to
Finally, referring to
In brief, the crucible structure 100 in the embodiment uses the raw material (i.e. can be solely the barium compound material, or a mixture of the barium compound material and silicon nitride) of release coating layer 120a with the barium compound material having barium carbonate, barium oxide or barium hydroxide in replace of conventional silicon nitride layer. By being heated with the crucible body 110, the raw material of release coating layer 120a is formed into the release coating layer 120 that directly covers the crucible body 110 with the material including barium silicate or a mixture of barium silicate and silicon nitride. The barium silicate is a continuous film, and the thickness T of the release coating layer 120 is between 35 μm and 350 μm. As compared with the spraying cost of conventional crucible, since the crucible structure 100 in the embodiment uses the release coating layer 120, not only that the manufacturing cost can be reduced effectively, the probability that impurities falling into the subsequently formed silicon crystal structure can be effectively decreased or avoided.
It should be indicated that the following embodiments use the reference numerals and a part of the descriptions mentioned in the previous embodiments, wherein the same reference numbers are used to denote identical or similar elements. Meanwhile, the same technical content is omitted. Please refer to the previous embodiments for the omitted descriptions; no repetitions are incorporated into the following embodiments.
Referring to
Next, referring to
Subsequently, referring to
Briefly, in the manufacturing method of the silicon crystal structure 10 described in the embodiment, the formation of the release coating layer 120 and the formation of silicon crystal structure 10 are combined into a single batch reaction. That is, the raw material of release coating layer 120a and the crucible body 110 are reacted first to form the release coating layer 120 that directly covers the crucible body 110, and then the silicon crystal structure 10 is formed. The above manufacturing method makes it possible to avoid the problem the high temperature causes the crucible body 110 to be softened while ensuring completeness of the reaction of the release coating layer 120. Accordingly, the cost for performing spraying powder on the crucible body 110 can be reduced and the probability that the impurity permeating through the silicon crystal structure 10 can be effectively decreased or avoided. It should be pointed out that, in the manufacturing method of the silicon crystal structure 10 performed in other embodiments, as long as the crucible structure in the above embodiment is not substantially damaged after completion, the crucible structure in the above embodiments can be used directly to conduct the subsequent crystal growth process without having to be combined for the single batch reaction. The crystal growth process is a conventional technology, and therefore no further descriptions are incorporated herein.
In summary of the above, the crucible structure of the invention uses the release coating layer that contains barium silicate or a mixture of barium silicate and silicon nitride as the material in replace of conventional purity silicon nitride layer, wherein the barium silicate is a continuous film for contacting the silicon crystal structure, and the thickness of the release coating layer is between 35 μm and 350 μm. As compared with the spraying cost for conventional crucible, the release coating layer used for the crucible structure of the invention not only can effectively lower the manufacturing cost, but also effectively reduce or avoid the probability that impurity falls into the silicon crystal structure formed in the subsequent process.
In addition, in the manufacturing method of the silicon crystal structure of the invention, the formation of the release coating layer and the formation of the silicon crystal structure are combined as a single batch reaction. That is, the raw material of release coating layer is reacted with the crucible body first to form the release coating layer that directly covers the crucible body, and the silicon crystal structure is formed afterwards. The above method can avoid the problem that high temperature causes the crucible body to be softened while ensuring completeness of reaction of the release coating layer. Accordingly, the spraying cost required for the crucible body can be decreased, and the probability that impurity falls into the silicon crystal structure can be effectively reduced or avoided.
Although the invention has been disclosed by the above embodiments, the embodiments are not intended to limit the invention. It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the invention without departing from the scope or spirit of the invention. Therefore, the protecting range of the invention falls in the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 106114197 | Apr 2017 | TW | national |
