Tubular oxidation diffusion furnace

Abstract

The invention discloses a tubular oxidation diffusion furnace, and relates to the technical field of oxidation diffusion furnaces, the tubular oxidation diffusion furnace comprises a thermal insulation layer, a heating assembly is arranged in the thermal insulation layer, an outer furnace tube is fixedly mounted in the thermal insulation layer, and an inner furnace tube is slidably mounted in the outer furnace tube; the inner end of the inner furnace tube is provided with a circular groove, and the outer end of the inner furnace tube is provided with an end cover. An air inlet and an air outlet are formed in the inner furnace tube, and an air inlet groove and an air outlet groove are formed in the outer furnace tube; the heat preservation layer is provided with an air inlet channel and an air outlet channel. A sealing plate is installed on the heat preservation layer in a sliding mode, and a through groove is formed in the sealing plate. The inner furnace tube can translate relative to the outer furnace tube, and when an operator opens the end cover to take out the quartz boat, the temperature of air overflowing from the inner furnace tube is low, so that hidden dangers cannot be caused to the personal safety of the operator. In the process that the inner furnace tube is pushed by external force to move inwards to be reset, hot air in the outer furnace tube returns to the inner furnace tube through the circular groove, heat needed for preheating before next oxidation operation is small, and energy consumption of equipment is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of oxidation diffusion furnaces, in particular to a tubular oxidation diffusion furnace. Background Art

[0002] The tubular oxidation diffusion furnace is a key equipment used in semiconductor manufacturing and microelectronics processes. It is mainly used for high-temperature oxidation, doping or annealing processes on the surface of silicon wafers (wafers). Its core function is to form an oxide layer on the surface of the silicon wafer or diffuse impurity atoms into the silicon material by precisely controlling the temperature, gas environment and time, thereby changing the electrical properties of the material. In terms of structure, the tubular oxidation diffusion furnace is mainly composed of high-temperature resistant furnace tubes, multi-point resistance wire heating elements, precise atmosphere control systems and temperature control systems. The furnace tube design needs to adapt to different wafer specifications, the heating elements ensure uniform temperature distribution in the furnace, the atmosphere control system accurately regulates the circulation of the oxidizing atmosphere, and the temperature control system ensures the accuracy of the process temperature through real-time monitoring and regulation.

[0003] For example, a tubular diffusion furnace disclosed in a Chinese utility model patent with publication number CN207353273U includes a diffusion furnace tube and a heating module, wherein the heating module heats the diffusion furnace tube so that the temperature in the diffusion furnace tube increases along the direction in which the process gas is charged into the diffusion furnace tube. The temperature in the diffusion furnace tube increases along the direction in which the process gas is charged into the diffusion furnace tube. In the diffusion process, the temperature in the diffusion furnace tube can be increased along the charging direction of the diffusion furnace tube, so that the temperature at a location with a higher concentration of process gas in the diffusion furnace tube is lower, and the temperature at a location with a lower concentration of process gas is higher.

[0004] For another example, a vertical diffusion furnace nozzle disclosed in a Chinese utility model patent with publication number CN220265945U includes a first nozzle and a second nozzle, an air inlet is arranged at one end of the first nozzle and the second nozzle, the first nozzle is longer than the second nozzle, and side walls of the first nozzle and the second nozzle are both provided with spray holes; the spray holes on the second nozzle are arranged along the side walls of the second nozzle, and the spray holes on the first nozzle are arranged along the side walls of the first nozzle that are longer than the second nozzle, and the spray holes are used to spray airflow toward both sides of the first nozzle and the second nozzle.

[0005] In actual use, the high-temperature residual gas in the furnace needs to be discharged after the oxidation is completed to prevent the high-temperature gas in the furnace from quickly overflowing from the furnace mouth after the operator opens the furnace cover, posing a hidden danger to the operator's personal safety. However, after the high-temperature gas overflows, the temperature in the furnace decreases, and the furnace body needs to be preheated for the next oxidation operation, which results in high energy consumption of the equipment. Summary of the invention

[0006] The object of the present invention is to provide a tubular oxidation diffusion furnace to solve the above-mentioned deficiencies in the prior art.

[0007] In order to achieve the above object, the present invention provides the following technical solution: a tubular oxidation diffusion furnace, comprising a heat-insulating layer, a heating assembly arranged in the heat-insulating layer, an outer furnace tube fitted therewith fixedly installed in the heat-insulating layer, an inner furnace tube slidably installed in the outer furnace tube along its length direction; a circular groove is provided at the inner end of the inner furnace tube, and an end cap is installed at the outer end of the inner furnace tube; The inner furnace tube is provided with an air inlet hole and an air outlet hole, and the outer furnace tube is provided with an air inlet groove cooperating with the air inlet hole and an air outlet groove cooperating with the air outlet hole; the thermal insulation layer is provided with an air inlet duct cooperating with the air inlet groove and an air outlet duct cooperating with the air outlet groove; a sealing plate cooperating with the air outlet duct is slidably installed on the thermal insulation layer, and a through groove is provided on the sealing plate.

[0008] As a preferred technical solution of the present invention, a first rack is fixedly installed at one end of the sealing plate, a sliding rod that penetrates the insulation layer and the outer furnace tube is slidably installed at the position of the insulation layer corresponding to the inner furnace tube, a second rack is fixedly installed on the sliding rod, and a gear is rotatably installed on the outside of the insulation layer through a bracket, and the first rack and the second rack are both engaged with the gear.

[0009] As a preferred technical solution of the present invention, a torsion spring is installed between the end of the gear and the bracket.

[0010] As a preferred technical solution of the present invention, when the outer end surface of the inner furnace tube is in contact with the inner end surface of the outer furnace tube, the positions of the air outlet hole, the air outlet channel and the through groove correspond to each other; when the positions of the air outlet hole and the air outlet channel do not correspond to each other, the positions of the through groove and the air outlet channel do not correspond to each other.

[0011] As a preferred technical solution of the present invention, a circular mesh structure is installed at a position corresponding to the circular groove on the inner furnace tube; a graphene plate is installed at a position corresponding to the circular groove on the inner end surface of the outer furnace tube; a first inclined groove corresponding to the bottom end of the graphene plate is provided on the outer furnace tube, and a second inclined groove connected to the first inclined groove is provided on the insulation layer.

[0012] As a preferred technical solution of the present invention, the diameter of the mesh structure is consistent with the diameter of the circular groove, a vertical rotating shaft is installed on the top of the mesh structure, and a strip groove matching the top of the rotating shaft is opened on the inner circumferential surface of the outer furnace tube, and the strip groove is parallel to the axis of the outer furnace tube.

[0013] As a preferred technical solution of the present invention, a fixed sleeve on the rotating shaft is provided with a gear ring located in the strip groove, a receiving groove is provided in the strip groove, an inclined guide groove is provided in the receiving groove, and a third rack matching the guide groove is installed in the receiving groove; a telescopic spring is connected between one end of the third rack and the end face of the strip groove.

[0014] As a preferred technical solution of the present invention, a ball rollingly engaged with the guide groove is installed on the third rack.

[0015] In the above technical scheme, the present invention provides a tubular oxidation diffusion furnace, in which the inner furnace tube can be translated relative to the outer furnace tube. After the oxidation diffusion treatment is completed, in the process of pulling the inner furnace tube outward by external force, the hot air in the inner furnace tube will enter the outer furnace tube through the circular groove, while the air with lower external temperature will enter the inner furnace tube. When the operator opens the end cover to take out the quartz boat, the air overflowing from the inner furnace tube has a lower temperature and will not cause hidden dangers to the personal safety of the operator. In the process of pushing the inner furnace tube inward to move and reset by external force, the hot air in the outer furnace tube returns to the inner furnace tube through the circular groove. In this way, less heat is required for preheating before the next oxidation operation, reducing the energy consumption of the equipment.

[0016] In addition, during the wet oxidation process, when hot air passes through the mesh structure in the circular groove, water vapor will adhere to the mesh structure to form water droplets; the inner furnace tube reciprocates once, and the water vapor will pass through the mesh structure twice. The impurities in the water vapor will follow the water vapor and adhere to the mesh structure, and be adsorbed by the graphene plate, and finally discharged from the inner furnace tube, thus avoiding contamination of the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0018] Figure 1 Schematic diagram of the first state of the interior of the tubular oxidation diffusion furnace in the embodiment; Figure 2 for Figure 1 The enlarged schematic diagram of point A in the middle; Figure 3 Schematic diagram of the second state of the tubular oxidation diffusion furnace in the embodiment; Figure 4 for Figure 3 The enlarged schematic diagram of point B in the middle; Figure 5 for Figure 3 The enlarged schematic diagram of the center C; Figure 6 Schematic diagram of the three-dimensional structure of the inner furnace tube in the embodiment.

[0019] Description of reference numerals: 1. Insulation layer; 101. Air inlet; 102. Air outlet; 103. Second chute; 2. Heating assembly; 3. Outer furnace tube; 301. Air inlet slot; 302. Air outlet slot; 303. First chute; 304. Strip slot; 305. Accommodating slot; 306. Guide slot; 4. Inner furnace tube; 401. Circular slot; 402. Air inlet hole; 403. Air outlet hole; 5. End cover; 6. Sealing plate; 601. Through slot; 7. First rack; 8. Sliding rod; 9. Second rack; 10. Bracket; 11. Gear; 12. Mesh structure; 13. Graphene plate; 14. Rotating shaft; 15. Gear ring; 16. Third rack; 17. Telescopic spring. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0021] like Figure 1 As shown, this embodiment provides a tubular oxidation diffusion furnace, including a thermal insulation layer 1, which plays a role of heat insulation. A heating component 2 is arranged in the thermal insulation layer 1, and the heating component 2 is a prior art, specifically a resistance coil; an outer furnace tube 3 is fixedly installed in the thermal insulation layer 1 to fit the outer furnace tube 3, and an inner furnace tube 4 is slidably installed in the outer furnace tube 3 along its length direction; the heating component 2 generates heat after being energized, thereby increasing the temperatures of the outer furnace tube 3 and the inner furnace tube 4; a circular groove 401 coaxial with the inner furnace tube 4 is opened on the inner end surface of the inner furnace tube 4, and an end cover 5 is installed at the outer end of the inner furnace tube 4, and the end cover 5 and the inner furnace tube 4 are connected by threads or other commonly used methods in the prior art.

[0022] Specifically, the quartz boat carrying the wafers is placed in the inner furnace tube 4, and a support frame (not shown in the figure) for supporting the quartz boat is provided in the inner furnace tube 4; in the working state, the heating component 2 heats the inner furnace tube 4, so that the air temperature in the inner furnace tube 4 increases, and the wafers on the quartz boat are oxidized and diffused; after the oxidation is completed, the inner furnace tube 4 is pulled outward by external force, and then the end cover 5 is opened, the quartz boat is taken out, and the wafers on the quartz boat are unloaded.

[0023] like Figure 1 , Figure 3 and Figure 5As shown, the inner furnace tube 4 is provided with an air inlet hole 402 and an air outlet hole 403, and the outer furnace tube 3 is provided with an air inlet groove 301 matched with the air inlet hole 402 and an air outlet groove 302 matched with the air outlet hole 403; the thermal insulation layer 1 is provided with an air inlet passage 101 matched with the air inlet groove 301 and an air outlet passage 102 matched with the air outlet groove 302; a sealing plate 6 matched with the air outlet passage 102 is slidably mounted on the thermal insulation layer 1, and a through groove 601 is provided on the sealing plate 6. When the outer end surface of the inner furnace tube 4 is in contact with the inner end surface of the outer furnace tube 3, the positions of the air outlet hole 403, the air outlet passage 102 and the through groove 601 correspond; when the positions of the air outlet hole 403 and the air outlet passage 102 do not correspond, the positions of the through groove 601 and the air outlet passage 102 do not correspond.

[0024] Figure 1 In this state, the external oxygen passes through the pure water and then enters the inner furnace tube 4 through the air inlet 101, the air inlet groove 301 and the air inlet hole 402, and the residual gas inside the inner furnace tube 4 is discharged through the air outlet groove 302, the air outlet 102 and the through groove 601; after the gas filling is completed, the position of the sealing plate 6 is adjusted by external force so that the through groove 601 and the air outlet 102 are staggered to ensure that when the inner furnace tube 4 is in a high temperature and high pressure state, no internal gas will overflow from the through groove 601; the heating component 2 generates heat after being powered on, thereby increasing the temperature inside the inner furnace tube 4, so that the inner furnace tube 4 is in a high temperature and high pressure state, thereby oxidizing and diffusing the wafers on the quartz boat. After the oxidation is completed, the position of the sealing plate 6 is adjusted by external force so that the through groove 601 returns to the position corresponding to the air outlet 102, so that part of the high-pressure gas in the inner furnace tube 4 can be discharged from the inner furnace tube 4. Then, the inner furnace tube 4 is pulled to the right by external force to enter Figure 3 The state shown; during this process, the sealing plate 6 closes the air outlet 102, and the high temperature gas in the inner furnace tube 4 enters the outer furnace tube 3 through the circular groove 401, and the external air enters the inner furnace tube 4 through the air inlet 402; after pulling the inner furnace tube 4 to the predetermined position, the operator opens the end cover 5 to take out the quartz boat. Since the high temperature gas in the inner furnace tube 4 enters the outer furnace tube 3, the temperature of the gas overflowing from the inner furnace tube 4 is relatively low, which will not cause a safety hazard to the operator. After the operator removes the oxidized wafer, he places a new wafer on the quartz boat, and places the quartz boat in the inner furnace tube 4, then installs the end cover 5, and then pushes the inner furnace tube 4 back to the left. Figure 1 In this process, the high-temperature gas in the outer furnace tube 3 returns to the inner furnace tube 4 through the circular groove 401, and the air in the inner furnace tube 4 is discharged through the air inlet 402; in summary, the outer furnace tube 3 plays a role in temporarily storing the high-temperature gas in the inner furnace tube 4 during the whole process, that is, during the material taking process, the high-temperature gas in the inner furnace tube 4 enters the outer furnace tube 3, and during the material feeding process, the high-temperature gas returns to the inner furnace tube 4. In this way, it can avoid the potential safety hazard caused by high-temperature gas to the operator, and reduce the heat required for preheating during the next oxidation, thereby reducing energy consumption.

[0025] like Figure 1 and Figure 3 As shown, a first rack 7 is fixedly installed at one end of the sealing plate 6, a sliding rod 8 penetrating the insulation layer 1 and the outer furnace tube 3 is slidably installed at a position corresponding to the inner furnace tube 4 on the insulation layer 1, and a second rack 9 is fixedly installed on the sliding rod 8. A gear 11 is rotatably installed on the outside of the insulation layer 1 through a bracket 10, and the first rack 7 and the second rack 9 are both engaged with the gear 11; a torsion spring is installed between the end of the gear 11 and the bracket 10.

[0026] Specifically, in Figure 1 In this state, the end face of the inner furnace tube 4 is in contact with the outer furnace tube 3, the right end of the sealing plate 6 is in contact with the end face of the inner furnace tube 4, the gear 11 and the torsion spring between the bracket 10 are in a deformed state, and the gear 11 tends to rotate clockwise, but due to the obstruction of the sealing plate 6 by the inner furnace tube 4, the gear 11, the first rack 7 and the sealing plate 6 all maintain a stable and static state; when the inner furnace tube 4 moves to the right under the action of external force, the gear 11 will move clockwise under the action of the torsion spring, and drive the first rack 7 and the sealing plate 6 to move to the left, thereby automatically realizing the adjustment of the through groove 601.

[0027] During the actual wet oxidation process, the high-temperature and high-pressure water vapor in the inner furnace tube 4 will vaporize the impurities remaining in the inner furnace tube 4. The water vapor mixed with impurities will have an adverse effect on the quality of subsequent wafer oxidation, and these impurities will adhere to the inner wall of the inner furnace tube 4 at room temperature and are difficult to clean. To address this problem, the present embodiment also has the following design.

[0028] like Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, a circular mesh structure 12 is installed at a position corresponding to the circular groove 401 on the inner furnace tube 4, the mesh structure 12 is 200 mesh, and the thickness of the mesh structure 12 does not exceed 1 cm; a graphene plate 13 is installed at a position corresponding to the circular groove 401 on the inner end surface of the outer furnace tube 3, and the graphene plate 13 is resistant to high temperature and has water absorption; a first inclined groove 303 corresponding to the bottom end of the graphene plate 13 is opened on the outer furnace tube 3, and a second inclined groove 103 connected to the first inclined groove 303 is opened on the insulation layer 1; the diameter of the mesh structure 12 is consistent with the diameter of the circular groove 401, and a vertical The rotating shaft 14 is provided with a strip groove 304 which cooperates with the top of the rotating shaft 14 on the inner circumferential surface of the outer furnace tube 3, and the strip groove 304 is parallel to the axis of the outer furnace tube 3; a gear ring 15 located in the strip groove 304 is fixedly sleeved on the rotating shaft 14, a receiving groove 305 is provided in the strip groove 304, an inclined guide groove 306 is provided in the receiving groove 305, a third rack 16 which cooperates with the guide groove 306 is installed in the receiving groove 305, and a ball rolling with the guide groove 306 is installed on the third rack 16; a telescopic spring 17 is connected between one end of the third rack 16 and the end surface of the strip groove 304.

[0029] Specifically, when the inner furnace tube 4 is Figure 1 When the inner furnace tube 4 moves to the right in the state, the high-temperature water vapor in the inner furnace tube 4 passes through the mesh structure 12 from right to left. After the water vapor contacts the mesh structure 12, part of the water vapor forms water droplets on the right side of the mesh structure 12, and part of the impurities in the water vapor are also mixed in the water droplets and attached to the mesh structure 12; as the inner furnace tube 4 continues to move to the right, the ring gear 15 and the third rack 16 enter a meshing state. Since the third rack 16 cannot move to the right under the support of the telescopic spring 17, the ring gear 15 will rotate under the reaction force of the third rack 16. Specifically, when the inner furnace tube 4 moves to the right to a predetermined position, the ring gear 15 drives the The rotating shaft 14 and the mesh structure 12 rotate 180°; it should be noted that there is a certain damping between the rotating shaft 14 and the inner furnace tube 4, so only an external force exceeding a certain value can drive the ring gear 15 and the rotating shaft 14 to rotate; when the inner furnace tube 4 moves horizontally to the left from the rightmost position, the ring gear 15 will drive the third rack 16 meshing therewith to move left, and the telescopic spring 17 will be stretched. During the process of the third rack 16 moving left, it moves downward relative to the ring gear 15 under the guidance of the guide groove 306 until it is completely separated from the ring gear 15. After being separated from the ring gear 15, the third rack 16 is reset to its original position under the action of the telescopic spring 17. Figure 2The state shown; during the movement of the inner furnace tube 4 to the left, the high-temperature water vapor in the outer furnace tube 3 passes through the mesh structure 12 from left to right. After the water vapor contacts the mesh structure 12, part of the water vapor forms water droplets on the left side of the mesh structure 12; in this way, during the reciprocating translation of the inner furnace tube 4, water droplets are formed on the same side thereof, and the side will fit with the graphene plate 13, the graphene plate 13 adsorbs the water droplets on the mesh structure 12, and the moisture in the graphene plate 13 will gather downward under the action of gravity and be discharged through the first chute 303 and the second chute 103. To sum up, in this embodiment, the water vapor is liquefied through the flow of water vapor during the reciprocating translation of the inner furnace tube 4, so that some impurities follow the liquefied water vapor and adhere to the mesh structure 12 and are discharged; during the movement and reversing process of the inner furnace tube 4, the mesh structure 12 will also automatically rotate 180°, so that the liquefied water vapor exists on the surface of only one side of the mesh structure 12, thereby facilitating the graphene plate 13 to adsorb water droplets; in this way, the impurity content in the inner furnace tube 4 can be reduced and the oxidation quality of the wafer can be improved.

[0030] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A tubular oxidation diffusion furnace, comprising a heat-insulating layer (1), wherein a heating component (2) is arranged in the heat-insulating layer (1), characterized in that: An outer furnace tube (3) is fixedly installed in the insulation layer (1) and is fitted therewith. An inner furnace tube (4) is slidably installed in the outer furnace tube (3) along its length direction. A circular groove (401) is provided at the inner end of the inner furnace tube (4), and an end cover (5) is installed at the outer end of the inner furnace tube (4). The inner furnace tube (4) is provided with an air inlet hole (402) and an air outlet hole (403); the outer furnace tube (3) is provided with an air inlet groove (301) cooperating with the air inlet hole (402) and an air outlet groove (302) cooperating with the air outlet hole (403); the thermal insulation layer (1) is provided with an air inlet passage (101) cooperating with the air inlet groove (301) and an air outlet passage (102) cooperating with the air outlet groove (302); A sealing plate (6) cooperating with the air outlet duct (102) is slidably mounted on the thermal insulation layer (1), and a through groove (601) is provided on the sealing plate (6).

2. A tubular oxidation diffusion furnace according to claim 1, characterized in that: A first rack (7) is fixedly mounted on one end of the sealing plate (6); a sliding rod (8) penetrating the thermal insulation layer (1) and the outer furnace tube (3) is slidably mounted on the thermal insulation layer (1) at a position corresponding to the inner furnace tube (4); a second rack (9) is fixedly mounted on the sliding rod (8); a gear (11) is rotatably mounted on the outside of the thermal insulation layer (1) via a bracket (10); and both the first rack (7) and the second rack (9) are meshed with the gear (11).

3. A tubular oxidation diffusion furnace according to claim 2, characterized in that: A torsion spring is installed between the end of the gear (11) and the bracket (10).

4. A tubular oxidation diffusion furnace according to claim 3, characterized in that: When the outer end surface of the inner furnace tube (4) is in contact with the inner end surface of the outer furnace tube (3), the positions of the air outlet hole (403), the air outlet passage (102) and the through groove (601) correspond; when the positions of the air outlet hole (403) and the air outlet passage (102) do not correspond, the positions of the through groove (601) and the air outlet passage (102) also do not correspond.

5. The tubular oxidation diffusion furnace according to claim 4, characterized in that: A circular mesh structure (12) is installed at a position corresponding to the circular groove (401) on the inner furnace tube (4); a graphene plate (13) is installed at a position corresponding to the circular groove (401) on the inner end surface of the outer furnace tube (3); a first inclined groove (303) corresponding to the bottom end of the graphene plate (13) is provided on the outer furnace tube (3), and a second inclined groove (103) connected to the first inclined groove (303) is provided on the thermal insulation layer (1).

6. The tubular oxidation diffusion furnace according to claim 5, characterized in that: The diameter of the mesh structure (12) is consistent with the diameter of the circular groove (401); a vertical rotating shaft (14) is installed on the top of the mesh structure (12); a strip groove (304) matching the top of the rotating shaft (14) is opened on the inner circumferential surface of the outer furnace tube (3); the strip groove (304) is parallel to the axis of the outer furnace tube (3).

7. The tubular oxidation diffusion furnace according to claim 6, characterized in that: A gear ring (15) is fixedly sleeved on the rotating shaft (14) and is located in the strip groove (304). A receiving groove (305) is provided in the strip groove (304). An inclined guide groove (306) is provided in the receiving groove (305). A third rack (16) matching the guide groove (306) is installed in the receiving groove (305); and a telescopic spring (17) is connected between one end of the third rack (16) and an end surface of the strip groove (304).

8. The tubular oxidation diffusion furnace according to claim 7, characterized in that: The third rack (16) is provided with a ball bearing that rolls in cooperation with the guide groove (306).

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