Patent Publication Number: US-2022235485-A1

Title: Apparatus of oxidation-combusting an ingot grower and method thereof

Description:
BACKGROUND 
     The embodiment relates to an apparatus of oxidation-combusting an ingot grower and method thereof. 
     In order to mass-produce most of the semiconductor chips or solar cells used in electronic products, a wafer is generally used as a substrate. 
     Such a wafer is mainly made by growing a single crystal ingot from a seed and then slicing it into a thin thickness, and the single crystal ingot can be manufactured by the Czochralski method (CZ method). 
     In the Czochralski method, silicon is placed in a quartz crucible in a chamber, the quartz crucible is heated to melt the silicon, and then the seed crystal is brought into contact with the silicon melt while rotating and gradually pulling up the seed from the surface of the single crystal. This is a method of growing an ingot having a predetermined diameter by solidifying the melt into a solid. 
     On the other hand, when growing a single crystal for manufacturing a low-resistance wafer for a power device, red phosphorus as an N-type dopant is doped on the wafer. 
     The volatilization point of red phosphorus is lower than the melting point of silicon constituting the wafer and volatilizes during single crystal growth, which is deposited on the inner surface of the chamber inner wall, exhaust pipe, filter housing, etc. to form deposits. 
     When such deposits react rapidly with oxygen and at the same time as friction during the final cleaning process, there is a risk of explosion, and thus a combustion process is performed through an oxidation reaction to remove them in a chemically safe state. 
     In the combustion process through oxidation reaction, the high-temperature deposits are exposed to the atmosphere, that is, external air, and combustion is performed through the oxidation reaction of air and deposits. 
     However, due to the ignition characteristics of red phosphorus, there is a problem in that dust explosion occurs during the combustion process, thereby exposing workers to danger. In addition, there is a risk of explosion due to friction in the subsequent cleaning process of deposits that are not combusted during the combustion process. 
     In addition, there is a problem in that the clay material generated during the combustion process passes through the filter housing and flows into the main pump, causing the main pump to be broken. 
     That is, when the deposits made of red phosphorus is exposed to the atmosphere, combustion occurs as shown in Chemical Formula 1 to produce oxides. 
       P 4 +3O 2 →P 4 O 6   [Chemical Formula 1]
 
     When the oxides generated by Chemical Formula 1 are exposed to moisture, a clay material is produced as shown in Chemical Formula 2. 
       P 4 O 6 +6H 2 O→4H 3 PO 3   [Chemical Formula 2]
 
     Since the clay material enters the main pump through the filter housing as a liquid, the main pump may be broken by the clay material. 
     SUMMARY 
     The embodiment aims to solve the above and other problems. 
     Another object of the embodiment is to provide an apparatus of oxidation-combusting an ingot grower and method thereof capable of completely removing deposits from a filter housing. 
     Another object of the embodiment is to provide an apparatus of oxidation-combusting an ingot grower and method thereof capable of easily removing deposits of a filter housing. 
     Another object of the embodiment is to provide an apparatus of oxidation-combusting an ingot grower and method thereof capable of preventing a failure of a main pump in advance. 
     According to an aspect of the embodiment to achieve the above or other objects, a method of oxidation-combusting an ingot grower comprising a chamber, an exhaust pipe connected to the chamber, and a filter housing connected to the exhaust pipe, the method comprising: a) blocking between the filter housing and the exhaust pipe; b) forming the filter housing in a vacuum state; and c) injecting air into the filter housing through an injection pipe connected to a first side of the filter housing to combust the filter housing. 
     According to another aspect of the embodiment, an apparatus of oxidation-combusting an ingot grower, the apparatus comprises: a chamber; an exhaust pipe connected to the chamber; a filter housing connected to the exhaust pipe; an injection pipe connected to a first side of the filter housing; and a controller, wherein the controller is configured to: block between the filter housing and the exhaust pipe and forming the filter housing in a vacuum state, and inject air into the filter housing through the injection pipe to combust the filter housing. 
     The effects of the apparatus of oxidation-combusting an ingot grower and method thereof according to the embodiment will be described as follows. 
     According to at least one of the embodiments, the filter housing is blocked from the exhaust pipe after single crystal growth, the filter housing is formed in a vacuum state, and the process of combusting the filter housing by injecting air is repeatedly performed, thereby completely removing deposits deposited on the filter housing. It has the advantage of being able to prevent failure of the main pump so that deposits do not flow into the main pump. 
     According to at least one of the embodiments, by injecting air into the chamber and the exhaust pipe by using a vacuum pump connected to the exhaust pipe after single crystal growth to combust the chamber and the exhaust pipe, it is possible to easily remove deposits deposited in the chamber and the exhaust pipe. 
     According to at least one of the embodiments, by forming the filter housing in a vacuum state, air is introduced into the filter housing at high speed, and the entire area of the filter housing is rapidly combusted so that deposits in the filter housing can be easily removed. 
     A further range of applicability of the embodiments will become apparent from the detailed description below. However, various changes and modifications within the spirit and scope of the embodiments may be clearly understood by those skilled in the art, and thus specific embodiments such as detailed description and preferred embodiments should be understood as being given by way of example only. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is a view showing an apparatus of oxidation-combusting an ingot grower according to an embodiment. 
         FIG. 2  is a flowchart illustrating a method of oxidation-combusting an ingot grower according to an embodiment. 
         FIG. 3  shows states of a plurality of valves for each period in the apparatus of oxidation-combusting the ingot grower of  FIG. 1 . 
         FIG. 4  shows the process of combusting the chamber and exhaust pipe. 
         FIG. 5  shows a process of forming the filter housing in a vacuum state. 
         FIG. 6  shows the process of combusting the filter housing. 
         FIG. 7  shows a process of circulating air in the filter housing. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, exemplary embodiments disclosed in the present specification will be described in detail with reference to the accompanying drawings, but identical or similar elements are denoted by the same reference numerals regardless of reference numerals, and redundant descriptions thereof will be omitted. The suffixes ‘module’ and ‘unit’ for constituent elements used in the following description are given or used interchangeably in consideration of the ease of preparation of the specification, and do not have themselves distinct meanings or roles. In addition, the accompanying drawings are for easy understanding of the embodiments disclosed in the present specification, and the technical spirit disclosed in the present specification is not limited by the accompanying drawings. Also, when an element such as a layer, region or substrate is referred to as being ‘on’ another elements, these include those that may exist directly on another element or may have other intermediate elements between them. 
     [Oxidation Combustion Apparatus] 
       FIG. 1  is a view showing an apparatus of oxidation-combusting an ingot grower according to an embodiment. 
     Referring to  FIG. 1 , the apparatus of oxidation-combusting the ingot grower according to the embodiment includes a chamber  110 , an exhaust pipe  120 , a filter housing  130 , an injection pipe  140 , a discharge pipe  150 , and a controller  160 . The apparatus of oxidation-combusting the ingot grower according to the embodiment may include more elements than these elements hereby, and elements not described below among the more elements can be easily understood from the prior art. 
     The chamber  110  is a member for growing a single crystal ingot which becomes a material for a wafer, which is a substrate of a semiconductor chip or a solar cell. During the growth of the single crystal ingot, the inside of the chamber  110  may be maintained in a vacuum state so that external foreign substances, etc. are not introduced into the single crystal ingot. 
     The chamber  110  may be connected to the main pump  180  through the exhaust pipe  120 . Air in the chamber  110  may be discharged by driving the main pump  180  so that the interior of the chamber  110  may be maintained in a vacuum state. Although not shown, an air injection pipe may be connected to one side of the exhaust pipe  120 . Air is introduced into the chamber  110  through the air injection pipe and the exhaust pipe  120  so that the vacuum inside the chamber  110  may be released. Accordingly, when the vacuum of the chamber  110  is formed, the main pump  180  is driven, and when the vacuum of the chamber  110  is released, air may be injected into the air injection tube. 
     The filter housing  130  is positioned between the main pump  180  and the exhaust pipe  120  to filter foreign substances supplied from the chamber  110  through the exhaust pipe  120 . 
     The injection pipe  140  is connected to a first side of the filter housing  130  to inject air in the atmosphere into the filter housing  130 . The discharge pipe  150  may connect the second vacuum pump  182  and a second side of the filter housing  130  to discharge air in the filter housing  130  to the outside. For example, a circulation structure through which air flows into the injection pipe  140 , the filter housing  130 , and the discharge pipe  150  is formed by the injection pipe  140 , the filter housing  130 , and the discharge pipe  150  so that a temperature of the filter housing  130  can be forcibly lowered. 
     Meanwhile, the apparatus of oxidation-combusting the ingot grower according to the embodiment may include a plurality of valves  191  to  195 . 
     The filter housing  130  may be connected to the exhaust pipe  120  through the first connection pipe  184 . For example, the first valve  191  may be installed in the first connection pipe  184  to connect or block the filter housing  130  and the exhaust period. 
     The main pump  180  may be connected to the filter housing  130  through the second connection pipe  185 . For example, the second valve  192  may be installed in the second connection pipe  185  to connect or block the main pump  180  and the filter housing  130 . 
     The third valve  193  may be installed in the injection pipe  140  to inject air in the atmosphere into the filter housing  130  or block it. 
     The fourth valve  194  may be installed in the discharge pipe  150  to discharge the air inside the filter housing  130  to the outside or block it. 
     The first vacuum pump  181  is installed on one side of the exhaust pipe  120  to discharge air introduced into the chamber  110  to the outside through the exhaust pipe  120 . 
     The fifth valve  195  is installed between the exhaust pipe  120  and the first vacuum pump  181  to discharge the air of the exhaust pipe  120  to the outside or block it. Although not shown, the exhaust pipe  120  and the first vacuum pump  181  may be connected by a connection pipe, and a fifth valve  195  may be installed in the corresponding exhaust pipe  120 . 
     Meanwhile, while the single crystal ingot is growing, a dopant such as red phosphorus is vaporized and deposited on the inner surfaces of the chamber  110 , the exhaust pipe  120 , and the filter housing  130  to form deposits. These deposits flow into the single crystal ingot and cause defects in the wafer produced from the single crystal ingot, and thus need to be removed. 
     The embodiment can be largely divided into a process of oxidizing combustion of the chamber  110  and the exhaust pipe  120  and a process of oxidizing combustion of the filter housing  130 . 
     As shown in  FIG. 3 , the chamber  110  and the exhaust pipe  120  are oxidation-combusted during the second period T 2 , and the filter housing  130  can be oxidation-combusted during the third to sixth periods (T 3  to T 6 ). 
     In addition, a single crystal ingot may be grown in the chamber  110  in the first period T 1 . 
     Accordingly, after the single crystal ingot is grown in the first period T 1 , the chamber  110 , the exhaust pipe  120 , and the filter housing  130  may be oxidation-combusted during the second to sixth periods T 2  to T 6 . That is, the first to sixth periods T 1  to T 6  constitute one cycle, and the chamber  110 , the exhaust pipe  120 , and the filter housing  130  may be oxidation-combusted every cycle, but this is not limited thereto. For example, the oxidation combustion process of the chamber  110 , the exhaust pipe  120 , and the filter housing  130  may be performed between the growth processes of each of the single crystal ingot. 
     According to the embodiment, after the chamber  110  and the exhaust pipe  120  are oxidation-combusted, the filter housing  130  is oxidation-combusted, but this is not limited thereto. For example, the filter housing  130  together with the chamber  110  and the exhaust pipe  120  may be oxidation-combusted at the same time, or after the filter housing  130  is oxidation-combusted, the chamber  110  and the exhaust pipe  120  may be oxidation-combusted. 
     The controller  160  may generally manage and/or control the ingot grower according to the embodiment. For example, the controller  160  may control the temperature and pressure of the chamber  110  and may control the vacuum state of the chamber  110 . 
     For example, the controller  160  may oxidation-combust the chamber  110 , the exhaust pipe  120 , and the filter housing  130  by controlling the first to fifth valves  191  to  195 . For example, the controller  160  may control a single crystal ingot to grow it in the chamber  110 . For example, the controller  160  may control the chamber  110 , the exhaust pipe  120 , and the filter housing  130  to be oxidation-combusted in order to remove deposits produced by the growth of the single crystal ingot. Specifically, the controller  160  blocks between the filter housing  130  and the exhaust pipe  120 , forms the filter housing  130  in a vacuum state, and injects air into the filter housing  130  through the injection pipe  140  to combust the filter housing  130 . Air can be contained in the atmosphere. 
     Meanwhile, the apparatus of oxidation-combusting the ingot grower according to the embodiment may include at least one temperature sensor  170 . 
     The temperature sensor  170  may be installed on one side of the filter housing  130  to measure the temperature of the filter housing  130 . For example, the temperature sensor  170  may be installed at a point far from the injection pipe  140 . Air in the atmosphere is injected into the filter housing  130  through the injection pipe  140  so that the deposits may be combusted by an oxidation reaction with the deposits of the filter housing  130 . Combustion may be performed along the traveling direction of the air injected from the injection pipe  140 . In the filter housing  130 , a region adjacent to the injection pipe  140  may be combusted first, and a region far from the injection pipe  140  may be combusted later. When the combustion is complete, the deposits are removed and there are no more deposits to be combusted so that the temperature may decrease in the region of the filter housing  130  in which combustion is completed. 
     For example, when the injection pipe  140  is installed on the upper side of the filter housing  130 , combustion may be performed first from the upper side of the filter housing  130  and then the combustion may proceed to the lower side of the filter housing  130 . Accordingly, the temperature may be higher at the lower side of the filter housing  130  than at the upper side of the filter housing  130 . 
     When the temperature measured from the lower side of the filter housing  130  is less than or equal to a predetermined temperature, it may be determined that combustion is completed not only at the upper side but also at the lower side of the filter housing  130 . Accordingly, when the injection pipe  140  is installed on the upper side of the filter housing  130 , the temperature sensor  170  may be installed on the lower side of the filter housing  130 . For example, each of the at least one temperature sensor  170  may be installed in at least one region of the lower side of the filter housing  130 . For example, each of the at least one temperature sensor  170  may be installed on a lower side of the filter housing  130  and/or a side region of a lower side of the filter housing  130 . The temperature sensor  170  may be exposed inside the filter housing  130 , but is not limited thereto. 
     Accordingly, the temperature sensor  170  may continuously measure the temperature of the filter housing  130  while the filter housing  130  is oxidation-combusted. 
     The controller  160  may continuously combust the filter housing  130  until the temperature measured by the temperature sensor  170  falls below a predetermined temperature. 
     [Oxidation-Combustion Method] 
       FIG. 2  is a flowchart illustrating a method of oxidation-combusting an ingot grower according to an embodiment.  FIG. 3  shows states of a plurality of valves for each period in the apparatus of oxidation-combusting the ingot grower of  FIG. 1 . 
     As shown in  FIGS. 1 and 3 , a single crystal ingot may be grown in the first period T 1 . To this end, the controller  160  may operate each of the first and second valves  191  and  192  in an ON state and operate each of the third to fifth valves  193  to  195  in an OFF state. Accordingly, an air circulation structure including the chamber  110 , the exhaust pipe  120 , the filter housing  130 , and the main pump  180  may be formed. The ON state may mean that the valve is open, and the OFF state may mean that the valve is closed. 
     After each of the first and second valves  191  and  192  is operated in the ON state and the third to fifth valves  193  to  195  are operated in the OFF state, the main pump  180  is operated to operate the chamber  110  to form a vacuum state. In such a vacuum state, a single crystal ingot can be grown. 
     While the single crystal ingot is grown in the first period T 1 , a dopant such as red phosphorus is vaporized and deposited on the inner surfaces of the chamber  110 , the exhaust pipe  120 , and the filter housing  130  to form deposits. 
     Referring to  FIG. 2 , after the single crystal ingot is grown, the controller  160  may combust the chamber  110  and the exhaust pipe  120  by introducing air into the chamber  110  and the exhaust pipe  120  (S 210 ). 
       FIGS. 1 and 3 , the chamber  110  and the exhaust pipe  120  may be combusted in the second period T 2 . 
     To this end, the controller  160  may operate each of the first to fourth valves  191  to  194  in an OFF state and may operate the fifth valve  195  in an ON state. Accordingly, an air circulation structure including the chamber  110 , the exhaust pipe  120 , and the first vacuum pump  181  may be formed. 
     Thereafter, as shown in  FIG. 4 , the controller  160  opens the cover  112  of the chamber  110  so that air in the atmosphere flows into the chamber  110  and operates the first vacuum pump  181 . Accordingly, air introduced into the chamber  110  may be discharged to the outside through the exhaust pipe  120  and the first vacuum pump  181 . Since the single crystal ingot is grown in a high temperature state in the first period T 1 , the chamber  110  and the exhaust pipe  120  or the deposits deposited in the chamber  110  and the exhaust pipe  120  may also be maintained at a high temperature. In this way, the high-temperature deposits may be oxidized by air and combustion may proceed. 
     The second period T 2  may be set in consideration of a time when the deposits of the chamber  110  and the exhaust pipe  120  are completely combusted. Accordingly, since both the deposits of the chamber  110  and the exhaust pipe  120  are combusted by the second period T 2 , the oxidation combustion of the chamber  110  and the exhaust pipe  120  may be completed. 
     Referring to  FIG. 2 , the controller  160  may block between the filter housing  130  and the exhaust pipe  120  and form the filter housing  130  in a vacuum state (S 220 ). 
       FIGS. 1 and 3 , a vacuum state may be formed in the filter housing  130  in the third period T 3 . To this end, the controller  160  may operate the second valve  192  in the ON state and operate the first and third to fifth valves  191  and  193  to  195  respectively in the OFF state. Accordingly, the filter housing  130  may be connected only to the main pump  180 . Thereafter, as shown in  FIG. 5 , the controller  160  may operate the main pump  180 . Accordingly, air in the filter housing  130  is discharged to the outside so that a vacuum state may be formed in the filter housing  130 . 
     The third period T 3  may be set in consideration of a time for reaching a predetermined pressure. 
     Thereafter, as shown in  FIGS. 1 and 3 , a vacuum state of the housing may be maintained in the fourth period T 4 . To this end, the controller  160  may operate each of the first to fifth valves  191  to  195  in an OFF state. 
     Referring to  FIG. 2 , the controller  160  may inject air into the filter housing  130  through the injection pipe  140  to combust the filter housing  130  (S 230 ). 
     As shown  FIGS. 1 and 3 , the filter housing  130  may be combusted in the fifth period T 5 . To this end, the controller  160  may operate the third valve  193  in an ON state, and may operate each of the first, second, fourth and fifth valves  191 ,  192 ,  194 , and  195  in an OFF state. Accordingly, the filter housing  130  may be connected only to the injection pipe  140 . 
     As shown in  FIG. 6 , since the third valve  193  is in an ON state, air in the atmosphere may be introduced into the filter housing  130  through the injection pipe  140 . Since the third valve  193  is opened while the filter housing  130  is maintained in a vacuum state, air in the atmosphere can be injected into the filter housing  130  at high speed. Accordingly, the deposits deposited on the inner surface of the filter housing  130  may be combusted and removed by an oxidation reaction with air. In particular, since air in the atmosphere is injected at high speed through the injection pipe  140 , the air rapidly proceeds from the upper side to the lower side of the filter housing  130  in which the injection pipe  140  is installed, and combustion can proceed from the top to the lower side of the filter housing  130  quickly. 
     In  FIG. 3 , although it is shown that the oxidation combustion of the filter housing  130  is performed once by T 3  to T 5 , the oxidation of the filter housing  130  is repeatedly performed with T 3  to T 5  as one cycle (S 240  in  FIG. 2 ). That is, combustion can be carried out multiple times. Accordingly, oxidation combustion of the filter housing  130  may be performed more quickly, and oxidation combustion of the entire area of the filter housing  130  may be possible. 
     Referring to  FIG. 2 , the controller  160  may determine whether the temperature of the filter housing  130  is greater than a predetermined temperature (S 250 ) or not. 
     As shown in  FIG. 1 , the temperature of the filter housing  130  may be measured by at least one temperature sensor  170  installed in the lower side of the filter housing  130 . The controller  160  may check whether the measured temperature is greater than a predetermined temperature or not. The predetermined temperature may be an ignition temperature of deposits deposited on the inner surface of the filter housing  130 . 
     Referring to  FIG. 2 , when the temperature of the filter housing  130  is greater than a predetermined temperature, the controller  160  forms a circulation structure through which air flows through the injection pipe  140 , the filter housing  130 , and the discharge pipe  150  (S 260 ). 
     As shown in  FIGS. 1 and 3 , when the temperature of the filter housing  130  is greater than a predetermined temperature in the sixth period T 6 , the temperature of the filter housing  130  may be lowered. To this end, the controller  160  can operate each of the third and fourth valves  193  and  194  in an ON state and operate each of the first, second and fifth valves  191 ,  192  and  195  in an OFF state. have. Accordingly, the filter housing  130  may be connected to the injection pipe  140  and the discharge pipe  150 . 
     As shown in  FIG. 7 , since each of the third and fourth valves  193  and  194  is in an ON state, air in the atmosphere is injected into the filter housing  130  through the injection pipe  140 , and the filter housing  130 , and the air injected into the filter housing  130  may be discharged to the outside through the discharge pipe  150 . Accordingly, since air in the atmosphere is continuously injected into the filter housing  130  and then discharged to the outside, the temperature of the filter housing  130  may be lowered. 
     As the temperature of the filter housing  130  is lowered, the possibility of explosion occurring during the combustion process may be reduced. 
     Referring to  FIG. 2 , when the temperature of the filter housing  130  is less than or equal to a predetermined temperature, the controller  160  may terminate the combustion process (S 270 ). When the temperature of the filter housing  130  is less than or equal to a predetermined temperature, it is determined that the combustion of the deposits is not performed in the filter housing  130  and combustion of the deposits are completed so that the combustion process may be terminated. 
     When the combustion process is terminated in this way, each of the first to fifth valves  191  to  195  may be controlled so that the single crystal ingot can be grown in the first period Ti again. 
     According to the embodiment, the chamber  110  and the exhaust pipe  120  as well as the filter housing  130  can be quickly oxidation-combusted. 
     According to the embodiment, the possibility of explosion during combustion in the filter housing  130  may be reduced to prevent a risk due to explosion. 
     The detailed description above should not be construed as restrictive in all respects and should be considered as illustrative. The scope of the embodiments should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the embodiments are included in the scope of the embodiments.