Source furnace control method and device

Abstract

The invention discloses a source furnace control method and device. The control method of the source furnace comprises the steps that in the crucible heating process, the temperature of the end is controlled to rise to a first preset temperature; controlling the base part to be heated to a second preset temperature, wherein the second preset temperature is smaller than the first preset temperature. In the heating process of the crucible, the end part is controlled to be heated to the first preset temperature, and when the source material has the adhesion characteristic, the residual source material at the end part and the source material on the baffle plate can be evaporated before a new beam is provided at the base part of the crucible, so that the residual source material at the end part and on the baffle plate can be reduced; and the probability of baffle adhesion caused by source material residues on the baffle is reduced. And then the base part is controlled to be heated to the second preset temperature, so that the source furnace can provide the beam of the source material to the substrate of the material to be deposited, normal use of the source furnace is realized, the use reliability and the use stability of the source furnace can be improved, and meanwhile, the use efficiency of the source material can be improved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of semiconductor devices, and particularly relate to a control method and device of a source furnace. BACKGROUND

[0002] Molecular beam epitaxy (MBE) is an ultrahigh vacuum thin film preparation technology developed in the late 1960s, and its core advantage is to control the composition, thickness and interface flatness of the thin film with atomic level precision. It is an "atomic level carving tool" for preparing advanced functional materials such as semiconductor heterojunctions, quantum wells, and superlattices. Its equipment forms a directional molecular / atomic beam by making the source material in an ultrahigh vacuum environment, precisely deposits on the substrate surface, realizes "layer by layer" atomic level growth, and is widely used in high-end fields such as semiconductors, optoelectronics and quantum devices. However, in the process of use, due to the adhesion characteristics of the source material in the source furnace, the baffle is easy to stick, which affects the normal use of the equipment. Exemplarily, the raw material in the source furnace can be In. SUMMARY

[0003] The present application provides a control method and device of a source furnace to reduce the sticking probability of the baffle and improve the use reliability and stability of the source furnace.

[0004] In a first aspect, embodiments of the present application provide a control method of a source furnace for preventing the baffle of the source furnace from sticking; the source furnace includes a crucible and the baffle, the baffle is used to adjust the beam provided by the crucible, the crucible includes a base and an end, the base is arranged on the side of the end away from the baffle; the control method of the source furnace includes:

[0005] controlling the end to be heated to a first preset temperature during the heating process of the crucible;

[0006] controlling the base to be heated to a second preset temperature, the second preset temperature is less than the first preset temperature.

[0007] Optionally, the control method of the source furnace further includes:

[0008] controlling the base to be cooled during the cooling process of the crucible;

[0009] controlling the end to be cooled.

[0010] Optionally, during the heating process of the crucible, before controlling the end to be heated to the first preset temperature, the control method of the source furnace further includes:

[0011] setting the difference between the first preset temperature and the second preset temperature.

[0012] Optionally, setting the difference between the first preset temperature and the second preset temperature includes:

[0013] The second power corresponding to the base heating is determined based on the second preset temperature;

[0014] The difference between the first preset temperature and the second preset temperature is determined based on the variation range of the second power relative to the first preset temperature.

[0015] Optionally, the difference between the first preset temperature and the second preset temperature is in the range of 60-190℃.

[0016] Optionally, the source furnace control method also includes:

[0017] When the number of times the crucible is heated reaches a preset value, the end is controlled to be heated to a third preset temperature.

[0018] Optionally, the third preset temperature is greater than the first preset temperature.

[0019] Optionally, the difference between the third preset temperature and the first preset temperature is greater than or equal to 50°C.

[0020] Secondly, embodiments of the present invention provide a control device for a source furnace, used to prevent the baffle of the source furnace from sticking; the source furnace includes a crucible and the baffle, the baffle being used to adjust the beam provided by the crucible, the crucible including a base and an end, the base being disposed on the side of the end away from the baffle; the control device for the source furnace includes:

[0021] The first control module is used to control the end to heat up to a first preset temperature during the crucible heating process;

[0022] The second control module is used to control the base to heat up to a second preset temperature, which is lower than the first preset temperature.

[0023] Optionally, the control device for the source furnace also includes:

[0024] The third control module is used to control the base to cool down during the crucible cooling process;

[0025] The fourth control module is used to control the cooling of the end.

[0026] The technical solution of this invention, during the heating process of the crucible, first controls the end to be heated to a first preset temperature. When the source material has adhesive properties, the residual source material at the end and on the baffle can be evaporated before a new beam is provided to the base of the crucible. This reduces the amount of source material remaining at the end and on the baffle, lowering the probability of the baffle sticking due to source material residue. Then, the base is heated to a second preset temperature, allowing the source furnace to provide a beam of source material to the substrate of the material to be deposited, enabling normal use of the source furnace. This improves the reliability and stability of the source furnace, and also increases the efficiency of source material utilization. Attached Figure Description

[0027] Figure 1 A schematic flowchart illustrating a source furnace control method provided in an embodiment of the present invention;

[0028] Figure 2 A schematic flowchart illustrating another source furnace control method provided in an embodiment of the present invention;

[0029] Figure 3 A schematic flowchart illustrating another source furnace control method provided in an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the structure of a source furnace control device provided in an embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram of the structure of another source furnace control device provided in an embodiment of the present invention. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0033] This invention provides a source furnace control method to prevent baffle adhesion. The source furnace can form a directional beam of source material in an ultra-high vacuum environment and precisely deposit it onto a substrate of the material to be deposited through the furnace opening, achieving film growth on the substrate. The source furnace includes a crucible and a baffle, the baffle being used to regulate the beam provided by the crucible. The crucible can be placed inside the cavity of the source furnace to hold the source material and can withstand the high-temperature environment of the source material during evaporation. The crucible includes a base and an end, the base being located on the side of the end away from the baffle. Specifically, the end of the crucible can be a crucible opening, i.e., the part where the beam of the source material exits from the crucible. The end of the crucible and the furnace opening are aligned in a straight line. During the operation of the source furnace, the source material inside the crucible can be ejected through the crucible opening, then exit the source furnace through the furnace opening, and precisely deposited onto the substrate of the material to be deposited. The base of the crucible can be a crucible substrate for holding the source material. The base is located on the side of the end furthest from the baffle, i.e., the end is adjacent to the baffle, so that the temperature of the end can affect the beam emission temperature. The baffle can be located between the crucible outlet and the substrate of the material to be deposited, for adjusting the beam supplied from the crucible outlet. Exemplarily, the baffle includes a main baffle, a source furnace shutter baffle, and a telescopic baffle. The main baffle can be located between the source furnace and the substrate of the material to be deposited, protecting the substrate from particle collisions and deposition within the cavity before growth, preventing contamination. The source furnace shutter baffle is installed at the furnace opening of each source furnace, controlling the emission of the molecular beam through rapid opening and closing, achieving switching control of different material beams. The telescopic baffle blocks the furnace opening inside the cavity in a telescopic manner, providing a more flexible beam control method for the source furnace. The source furnace control method provided in this embodiment can be applied to application scenarios where the source material has adhesive properties. The source furnace control method provided in this embodiment can be executed by a source furnace control device, which can be integrated into the source furnace controller. Figure 1 This is a flowchart illustrating a source furnace control method provided in an embodiment of the present invention. Figure 1 As shown, the control method for this source furnace includes:

[0034] S110. During the crucible heating process, the end temperature is controlled to rise to the first preset temperature;

[0035] Specifically, the substrate of the material to be deposited can be positioned opposite the furnace opening of the source furnace. During the process of the source furnace providing the beam, the crucible needs to be heated so that the source material inside the crucible forms a beam in a high-temperature, ultra-high vacuum environment, and is directionally deposited onto the substrate of the material to be deposited. The temperature of the base and ends of the crucible can be controlled independently to realize a multi-segment heating structure of the crucible, improving the stability and uniformity of the beam. Specifically, when the base of the crucible is heated, the source material inside the crucible can melt and evaporate in a high-temperature environment to provide the source material beam, determining the amount of beam provided by the crucible. When the ends of the crucible are heated, the temperature of the beam passing through the crucible opening can be adjusted, thereby achieving precise beam control and temperature compensation. During the process of heating the crucible, the temperature of the ends of the crucible can be controlled first so that its temperature can at least reach the boiling point of the source material, and the source material on the baffles near the ends evaporates under the influence of its temperature. When the source material has adhesive properties, the source material on the baffle can be evaporated before a new beam is provided at the base of the crucible. This reduces the amount of source material remaining on the baffle, lowers the probability of baffle adhesion due to source material residue, and improves the reliability and stability of the source furnace. For example, the source material can be In. The end of the crucible has a heating element for heating the end of the crucible upon power-up, controlling the temperature at the end of the crucible. The power required by the heating element is positively correlated with its temperature. The first preset temperature can be set according to the temperature of the source material during evaporation at the base, maintaining the temperature of the source material as it evaporates from the base to the end, thereby improving the stability and uniformity of the beam.

[0036] S120, control the base temperature to rise to the second preset temperature, the second preset temperature is lower than the first preset temperature.

[0037] Specifically, after heating the end of the crucible, the base of the crucible can be heated further to a second preset temperature. This controls the melting and evaporation of the source material within the base, forming a new beam of source material, which is then ejected from the end of the crucible and the furnace opening. For example, the base of the crucible has a heating wire arranged around it to heat the base when powered on, controlling the temperature of the base. The power required by the heating wire is directly proportional to its temperature. During beam ejection, the beam can be precisely controlled by a baffle. The second preset temperature can be set according to the boiling point of the source material, allowing it to evaporate and form a beam when heated at the base. Since the second preset temperature is lower than the first preset temperature, the first preset temperature maintains the beam temperature as the evaporated source material diffuses to the end, preventing beam deposition at the crucible end, improving beam stability and uniformity, and avoiding source material contamination and waste.

[0038] The technical solution of this embodiment, during the crucible heating process, first controls the end to be heated to a first preset temperature. When the source material has adhesive properties, the residual source material at the end and on the baffle can be evaporated before a new beam is provided to the base of the crucible. This reduces the amount of source material remaining at the end and on the baffle, lowering the probability of source material residue on the baffle causing adhesion. Then, the base is heated to a second preset temperature, allowing the source furnace to provide a beam of source material to the substrate of the material to be deposited, enabling normal use of the source furnace. This improves the reliability and stability of the source furnace, and also increases the efficiency of source material utilization.

[0039] Figure 2 This is a flowchart illustrating another source furnace control method provided in an embodiment of the present invention. Figure 2 As shown, the control method for this source furnace includes:

[0040] S210. During the crucible heating process, the end temperature is controlled to rise to the first preset temperature;

[0041] S220, control the base temperature to rise to the second preset temperature, the second preset temperature is lower than the first preset temperature.

[0042] S230. During the crucible cooling process, control the base to cool down;

[0043] Specifically, during the process of the source furnace stopping the beam supply, the crucible needs to be cooled to stop the melting and evaporation of the source material inside, thus avoiding waste and deposition at the crucible end. During the crucible cooling process, the base of the crucible can be cooled first to stop the melting and evaporation of the source material. When the beam is stopped by the baffle, the deposition of source material on the baffle can be stopped, reducing the probability of baffle adhesion caused by source material deposition. At this time, the end of the crucible is at the first preset temperature, meaning that the source material already deposited on the baffle can continue to evaporate at the end of the crucible, further reducing the amount of source material remaining on the baffle and lowering the probability of baffle adhesion caused by source material residue, thereby improving the reliability and stability of the source furnace. The temperature of the base after cooling can be room temperature.

[0044] S240, cooling is performed at the control end.

[0045] Specifically, after the base of the crucible has cooled down, the ends can be cooled down further to achieve complete cooling of the crucible. The temperature after the ends have cooled down can be room temperature.

[0046] It should be noted that the crucible cooling process is a strictly temperature-controlled process to avoid sudden temperature changes that could reduce the crucible's lifespan and beam accuracy. For example, during the crucible cooling process, natural cooling, cooling device cooling, stratified cooling, and multi-directional cooling can be employed.

[0047] In some embodiments, before the controlled end reaches a first preset temperature during the crucible heating process, the method further includes:

[0048] Set the difference between the first preset temperature and the second preset temperature.

[0049] Specifically, before using the source furnace, preset temperatures for the crucible after heating can be set, namely a first preset temperature at the crucible end and a second preset temperature at the base, to ensure that the crucible can provide a stable beam. For example, the range of the second preset temperature can be the boiling point range of the source material, and the first preset temperature can be higher than the second preset temperature, allowing for temperature compensation of the source material as it evaporates to the crucible end. After determining the ranges of the first and second preset temperatures, a difference between them can be set, ensuring that when the temperature at the crucible end rises to the first preset temperature and the temperature at the crucible base rises to the second preset temperature, the temperature stability of the source material at the crucible end is maintained, reducing deposition of the source material at the end. Furthermore, since the crucible end and base are an integrated structure, setting a difference between the first and second preset temperatures avoids an excessively large temperature difference between the crucible end and base. When the temperature at the crucible end is conducted to the crucible base, a large difference between the actual temperature at the crucible base and the second preset temperature can be avoided, thereby improving the accuracy of the beam. For example, the difference between the first preset temperature and the second preset temperature is in the range of 60-190℃. This allows the temperature at the end of the crucible to compensate for the temperature difference during the diffusion process of the source material, and also avoids an excessively large temperature difference between the end and the base of the crucible, thus improving the accuracy of the beam. For example, the difference between the first preset temperature and the second preset temperature can be 90℃ or 130℃.

[0050] In some embodiments, setting the difference between a first preset temperature and a second preset temperature includes:

[0051] The second power corresponding to the base heating is determined based on the second preset temperature;

[0052] Specifically, when the temperature of the crucible base is controlled by a heating structure, and the energy source of the heating structure is electrical energy, the second preset temperature is positively correlated with the electrical power required to control its heating. After determining the second preset temperature, the power exerted by the source furnace control device on the corresponding heating structure at the crucible base can be determined based on the second preset temperature and the required electrical power; this power is the second power. For example, when the heating structure at the crucible base is a heating wire, and it is heated by electrical energy, the source furnace control device heats the heating wire, and the power required to raise the temperature of the crucible base to the second preset temperature is the second power. The higher the temperature that the crucible base needs to be heated to, the greater the second power required by the heating wire.

[0053] The difference between the first preset temperature and the second preset temperature is determined based on the variation range of the second power relative to the first preset temperature.

[0054] Specifically, the end and base of the crucible are an integrated structure. When the temperature difference between the end and base of the crucible is too large, the temperature of the base will change with the temperature of the end. That is, after the end of the crucible heats up to the first preset temperature, it will drive the temperature of the base to rise. At this time, the heating structure of the base reduces the second power required to heat the base to the second preset temperature. The value of the reduction in second power caused by the above process is the range of variation of the second power based on the first preset temperature. It can be characterized by the ratio of the reduction in second power to the second power determined by the second preset temperature. By setting the range of variation of the second power based on the first preset temperature within a certain range, the conduction of the first preset temperature to the base of the crucible can be avoided, so that the difference between the actual temperature of the base and the second preset temperature is relatively large, thereby improving the accuracy of the beam. After determining the range of variation of the second power based on the first preset temperature, the difference between the first preset temperature and the second preset temperature can be determined based on the range of variation of the second power based on the first preset temperature, thereby avoiding a large difference between the actual temperature of the base and the second preset temperature, and thus improving the accuracy of the beam. For example, the variation range of the second power based on the first preset temperature is less than or equal to 15%, that is, the percentage of the reduction of the second power based on the first preset temperature to the second power determined by the second preset temperature is less than or equal to 15%.

[0055] In some embodiments, the source furnace control method further includes:

[0056] When the crucible reaches the preset number of heating cycles, the control end is heated to the third preset temperature.

[0057] Specifically, the number of times the crucible is heated represents the number of times the crucible provides a beam, i.e., the number of times the source furnace is used to deposit the film. The higher the number of times the crucible is heated, the higher the probability of baffle adhesion. When the number of times the crucible is heated reaches a preset value, the end of the crucible can be heated to a third preset temperature, causing the residual source material on the baffle to evaporate, essentially "cleaning" the baffle. This further reduces the probability of baffle adhesion and improves the reliability and stability of the source furnace. The third preset temperature is greater than or equal to the boiling point of the source material, allowing the residual source material on the baffle to evaporate. The preset value for the number of heating cycles can be set based on the amount of residual source material on the baffle during each use of the source furnace. The more source material remaining on the baffle each time, the smaller the preset value; the less source material remaining each time, the larger the preset value. For example, the preset value for the number of times the crucible is heated can be 21 times. When the source furnace is used for 5 hours each time, three times a day, the baffle can be "cleaned" once a week. The preset value for the number of times the crucible is heated can be 42 times. If the furnace is used for 5 hours each time, three times a day, the baffle can be cleaned once every two weeks.

[0058] In some embodiments, a third preset temperature greater than a first preset temperature can increase the degree and speed of evaporation of residual source material on the baffle, thereby improving the "cleaning" degree and speed of the baffle and further reducing the probability of baffle adhesion. For example, the difference between the third preset temperature and the first preset temperature is greater than or equal to 50°C to ensure the "cleaning" degree and speed of the baffle.

[0059] It should be noted that, based on the condition that the difference between the third preset temperature and the first preset temperature is greater than or equal to 50°C, the difference between the third preset temperature and the second preset temperature can be less than the preset difference, in order to avoid the phenomenon that the source material at the base of the crucible evaporates when the temperature at the end of the crucible is too high and is conducted to the base of the crucible.

[0060] Figure 3 This is a flowchart illustrating another source furnace control method provided in an embodiment of the present invention. Figure 3 As shown, the control method for this source furnace includes:

[0061] S310, Set the difference between the first preset temperature and the second preset temperature;

[0062] S320. During the crucible heating process, the end temperature is controlled to rise to the first preset temperature;

[0063] S330, control the base temperature to rise to the second preset temperature, the second preset temperature is lower than the first preset temperature.

[0064] S340. During the crucible cooling process, control the base to cool down;

[0065] S350, cooling is performed at the control end.

[0066] S360 When the crucible reaches the preset number of heating cycles, the control end is heated to the third preset temperature.

[0067] This invention also provides a source furnace control device for preventing the baffle of the source furnace from sticking together; the source furnace includes a crucible and a baffle, the baffle is used to adjust the beam provided by the crucible, the crucible includes a base and an end, the base is disposed on the side of the end away from the baffle. Figure 4 This is a schematic diagram of a source furnace control device provided in an embodiment of the present invention. Figure 4 As shown, the control device for the source furnace includes:

[0068] The first control module 10 is used to control the end temperature to rise to a first preset temperature during the crucible heating process;

[0069] The second control module 20 is used to control the base to heat up to a second preset temperature, which is lower than the first preset temperature.

[0070] In this embodiment, the technical solution involves a first control module that first heats the end of the crucible to a first preset temperature during the heating process. When the source material exhibits adhesive properties, the residual source material at the end and on the baffle can be evaporated before a new beam is provided to the base of the crucible. This reduces the amount of source material remaining at the end and on the baffle, lowering the probability of baffle adhesion caused by residual source material. Then, the second control module heats the base to a second preset temperature, enabling the source furnace to provide a beam of source material to the substrate of the material to be deposited, thus ensuring normal operation of the source furnace. This improves the reliability and stability of the source furnace and increases the efficiency of source material utilization.

[0071] In some embodiments, Figure 5 This is a schematic diagram of another source furnace control device provided in an embodiment of the present invention. Figure 5 As shown, the control device for the source furnace also includes:

[0072] The third control module 30 is used to control the base to cool down during the crucible cooling process;

[0073] The fourth control module 40 is used to control the cooling of the end.

[0074] In some embodiments, the control device for the source furnace further includes:

[0075] The setting module is used to set the difference between the first preset temperature and the second preset temperature.

[0076] In some embodiments, the setting module includes:

[0077] The first determining unit is used to determine the second power corresponding to the base heating based on the second preset temperature;

[0078] The second determining unit is used to determine the difference between the first preset temperature and the second preset temperature based on the variation range of the second power based on the first preset temperature.

[0079] In some embodiments, the difference between the first preset temperature and the second preset temperature ranges from 60 to 190°C.

[0080] In some embodiments, the control device for the source furnace further includes:

[0081] The fifth control module is used to control the end to heat up to the third preset temperature when the crucible reaches a preset number of heating cycles.

[0082] In some embodiments, the third preset temperature is greater than the first preset temperature.

[0083] In some embodiments, the difference between the third preset temperature and the first preset temperature is greater than or equal to 50°C.

[0084] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for controlling a source furnace, used to prevent the baffles of the source furnace from sticking together; characterized in that, The source furnace includes a crucible and a baffle plate, the baffle plate being used to adjust the beam provided by the crucible, the crucible including a base and an end, the base being disposed on the side of the end plate away from the baffle plate; the control method of the source furnace includes: During the crucible heating process, the end is controlled to heat up to a first preset temperature; The base is heated to a second preset temperature, which is lower than the first preset temperature.

2. The source furnace control method according to claim 1, characterized in that, Also includes: During the crucible cooling process, the base is controlled to cool down; The end is controlled to cool down.

3. The source furnace control method according to claim 1, characterized in that, Before controlling the end to heat up to the first preset temperature during the crucible heating process, the method further includes: Set the difference between the first preset temperature and the second preset temperature.

4. The source furnace control method according to claim 3, characterized in that, Setting the difference between the first preset temperature and the second preset temperature includes: The second power corresponding to the base heating is determined based on the second preset temperature; The difference between the first preset temperature and the second preset temperature is determined based on the variation range of the second power relative to the first preset temperature.

5. The source furnace control method according to claim 3, characterized in that, The difference between the first preset temperature and the second preset temperature is in the range of 60-190℃.

6. The source furnace control method according to any one of claims 1-5, characterized in that, Also includes: When the number of times the crucible is heated reaches a preset value, the end is controlled to be heated to a third preset temperature.

7. The source furnace control method according to claim 6, characterized in that, The third preset temperature is greater than the first preset temperature.

8. The source furnace control method according to claim 7, characterized in that, The difference between the third preset temperature and the first preset temperature is greater than or equal to 50°C.

9. A control device for a source furnace, used to prevent the baffles of the source furnace from sticking together; characterized in that, The source furnace includes a crucible and a baffle plate, the baffle plate being used to adjust the beam current provided by the crucible, the crucible including a base and an end, the base being disposed on the side of the end plate away from the baffle plate; the control device for the source furnace includes: The first control module is used to control the end to heat up to a first preset temperature during the crucible heating process; The second control module is used to control the base to heat up to a second preset temperature, which is lower than the first preset temperature.

10. The control device for the source furnace according to claim 9, characterized in that, Also includes: The third control module is used to control the base to cool down during the crucible cooling process; The fourth control module is used to control the cooling of the end.

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