Thermocouple sleeve

Abstract

The utility model provides a thermowell, which comprises an isolating tube, an inner-layer tube and an outer-layer cover. The isolation tube is used for accommodating a thermocouple; the inner-layer pipe comprises a ball bowl, and the isolation pipe penetrates through the ball bowl from the bowl bottom of the ball bowl; the outer-layer cover is arranged outside the inner-layer pipe, the side, close to the bowl bottom of the ball bowl, of the outer-layer cover is a cover top, the side, close to the bowl opening of the ball bowl, of the outer-layer cover is a cover bottom, the cover top is connected with the outer wall of the isolation pipe in a sealed mode, the cover bottom is open, and the inner-layer pipe is connected with the isolation pipe in a sealed mode. And the cover surface of the outer layer cover is provided with an air inlet pipe. Nitrogen is introduced into the outer layer cover through the gas inlet pipe of the outer layer cover, a nitrogen environment is formed in the area around the thermocouple inlet of the process pipe, oxygen in the atmosphere is effectively prevented from entering the process pipe, the sealing performance of the thermocouple inlet end of the process pipe is improved, the leakage rate is reduced, the situation that the uniformity of wafers is poor is reduced, and the stability of a machine table is improved.

Description

Technical Field

[0001] This utility model relates to the semiconductor field, and in particular to a thermocouple sheath. Background Technology

[0002] In existing vertical diffusion furnaces, the high-temperature furnace tube thermocouple (TC) inlet is located at the top of the machine, and both the gas inlet and thermocouple inlet of the process tube are located at the top of the process tube. The process tube is made of silicon carbide (SiC), while the thermocouple sheath is made of quartz. Because the temperature at the silicon carbide process tube inlet exceeds 600 degrees Celsius during processing, a sealing ring cannot be used. Instead, the quartz sheath and process tube are in direct contact, and a seal is achieved through the abrasive joint between them.

[0003] When the quartz sheath and process tube are in contact for extended periods, the contact surface of the process tube will wear down, leading to poor sealing at the thermocouple inlet. This allows oxygen from the air to enter the process tube, increasing the leakage rate at the thermocouple inlet. Furthermore, the sealing part of the thermocouple quartz sheath is a ball-and-cup structure, typically fixed directly with metal clips. This relatively small contact surface makes the ball-and-cup structure of the thermocouple quartz sheath prone to cracking during temperature fluctuations, further increasing the leakage rate at the process tube thermocouple inlet. Increased leakage results in poor wafer uniformity and may even lead to product scrap, severely impacting machine efficiency and production effectiveness.

[0004] Providing a thermocouple sheath that can reduce the leakage rate at the thermocouple inlet of the process tube and prevent oxygen from entering the process tube plays an important role in improving the stability of the machine and ensuring product quality. Summary of the Invention

[0005] The technical problem to be solved by this utility model is to provide a thermocouple sheath that can prevent atmospheric oxygen from entering the process tube, effectively solving the problem of poor sealing of the thermocouple inlet and high leakage rate in the process tube, thereby reducing the problem of poor wafer uniformity caused by high leakage rate and improving the reliability of the machine.

[0006] To address the aforementioned problems, this utility model provides a thermocouple sheath, comprising: an isolation tube, which is a cylindrical tube used to house the thermocouple; an inner tube, which includes a spherical cup, through which the isolation tube passes from the bottom of the spherical cup; and an outer cover, which is disposed outside the inner tube, with the side of the outer cover near the bottom of the spherical cup being the top cover and the side of the outer cover near the opening of the spherical cup being the bottom cover, the top cover being sealed to the outer wall of the isolation tube, the bottom cover being open, and an air inlet pipe on the surface of the outer cover.

[0007] In some embodiments, the inner tube further includes a connecting tube disposed at the bottom of the spherical bowl, with both ends of the connecting tube respectively in close contact with the outer wall of the isolation tube and the bottom of the spherical bowl.

[0008] In some embodiments, both the connecting tube and the outer cover are cylindrical in shape.

[0009] In some embodiments, the distance between the air intake pipe and the plane where the bottom of the cover is located is greater than the distance between the bottom of the bowl and the plane where the bottom of the cover is located.

[0010] In some embodiments, the intake pipe is used to introduce nitrogen gas.

[0011] In some embodiments, the materials of the isolation tube, the inner tube, and the outer cover are all quartz.

[0012] In some embodiments, the cross-sectional areas of the top and bottom of the outer cover are different.

[0013] In some embodiments, the inner tube and the outer cover are integrally formed.

[0014] In some embodiments, when the thermocouple sheath is connected to the process tube, the isolation tube is inserted into the pipeline of the process tube, and the inner wall of the ball cup is in direct contact with the spherical inlet end of the process tube to achieve a seal.

[0015] In some embodiments, a round rod is provided at the other end of the isolation tube, and an insertion hole is provided inside the process tube. The end of the round rod can be inserted into the insertion hole to fix the isolation tube to the process tube.

[0016] In some embodiments, the inner wall of the spherical bowl has a frosted surface.

[0017] The above technical solution provides a thermocouple sheath, including an isolation tube, an inner tube, and an outer cover. The isolation tube is a cylindrical tube used to house the thermocouple. The inner tube includes a spherical cup, and the isolation tube penetrates the bottom of the spherical cup. The outer cover is disposed outside the inner tube, with the top of the outer cover near the bottom of the spherical cup and the bottom of the outer cover near the opening of the spherical cup. The top of the outer cover is sealed to the outer wall of the isolation tube, while the bottom of the outer cover is open. An inlet pipe is located on the outer cover. Nitrogen gas is introduced into the quartz sheath through the inlet pipe of the outer cover, creating a nitrogen environment around the thermocouple inlet of the process tube. This effectively prevents atmospheric oxygen from entering the process tube, improves the sealing performance of the thermocouple inlet, reduces leakage, and consequently reduces the problem of poor wafer uniformity caused by high leakage, improving the stability of the equipment and ensuring product quality.

[0018] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the present invention. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a thermocouple sheath provided in one embodiment of the present invention;

[0021] Figure 2 This is a cross-sectional view of a thermocouple sheath provided in an embodiment of the present invention;

[0022] Figure 3 This is a partial cross-sectional view of the connection between the thermocouple sheath and the process tube provided in one embodiment of the present invention. Detailed Implementation

[0023] The technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0024] Please refer to this as well. Figures 1-3 ,in Figure 1 This is a schematic diagram of a thermocouple sheath provided in one embodiment of the present invention; Figure 2 This is a cross-sectional view of a thermocouple sheath provided in an embodiment of the present invention; Figure 3 This is a partial cross-sectional view of the connection between the thermocouple sheath and the process tube provided in one embodiment of the present invention.

[0025] like Figure 1As shown, the thermocouple sheath includes: an isolation tube 11, an inner tube 12, and an outer sheath 13. The isolation tube 11 is a cylindrical tube used to house the thermocouple. The inner tube 12 includes a ball-shaped cup 121, through which the isolation tube 11 passes from the bottom. The outer sheath 13 is disposed outside the inner tube 12. The side of the outer sheath 13 closest to the bottom of the ball-shaped cup 121 is the top, and the side closest to the opening of the ball-shaped cup 121 is the bottom. The top is sealed to the outer wall of the isolation tube 11, while the bottom is open. An air inlet pipe 131 is provided on the surface of the outer sheath 13.

[0026] In this embodiment, the inner tube 12 further includes a connecting tube 122, which is disposed at the bottom of the ball cup 121. The two ends of the connecting tube 122 are respectively in close contact with the outer wall of the isolation tube 11 and the bottom of the ball cup 121.

[0027] In some embodiments, the inner tube 12 includes only a ball cup 121, the bottom of which is directly and sealed to the outer wall of the isolation tube 11.

[0028] In this embodiment, the ball bowl 121 is completely located inside the outer cover 13, and the rim of the ball bowl 121 is at a distance from the plane of the bottom of the outer cover 13.

[0029] In this embodiment, the air intake pipe 131 is a cylindrical pipe, and the air intake pipe 131 is disposed on the side of the outer cover 13. The distance between the air intake pipe 131 and the plane where the bottom of the cover is located is greater than the distance between the bottom of the bowl and the plane where the bottom of the cover is located.

[0030] refer to Figure 2 The distance between the air intake pipe 131 and the plane containing the bottom of the outer cover 13 is D1, and the distance between the bottom of the spherical cup 121 and the plane containing the bottom of the outer cover 13 is D2, where D1 is greater than D2. Accordingly, refer to... Figure 3 When the thermocouple sheath is connected to the process tube, the thermocouple sheath is placed vertically, and the position of the air inlet pipe 131 is higher than the highest position of the ball cup 121.

[0031] The thermocouple sheath is used in a vertical configuration. Since nitrogen is less dense than air, it rises after entering the outer cover 13 through the inlet pipe 131. As the nitrogen increases, the outer cover 13 is filled with nitrogen from top to bottom. Furthermore, air in the outer cover 13 is discharged from the bottom, thus expelling oxygen from the outer cover 13. Simultaneously, because the distance D1 between the inlet pipe 131 and the plane containing the bottom of the outer cover 13 is greater than the distance D2 between the bottom of the ball cup 121 and the plane containing the bottom of the outer cover 13 (i.e., the inlet pipe 131 is positioned higher than the highest point of the ball cup 121), the ball cup 121 is more quickly surrounded by nitrogen, reducing the oxygen content at the thermocouple inlet of the process tube 15, which is in contact with the ball cup 121.

[0032] In some embodiments, the air inlet pipe 131 is disposed on the surface where the top of the outer cover 13 is located. Accordingly, in the vertical state, since the density of nitrogen is less than that of air, nitrogen enters the outer cover 13 from the air inlet pipe 131 and accumulates at the top inside the outer cover 13. As the amount of nitrogen increases, the outer cover 13 is filled with nitrogen from top to bottom, thereby expelling the air in the outer cover 13 from the bottom of the outer cover 13, thus expelling the oxygen in the outer cover 13. At the same time, since the distance D1 between the air inlet pipe 131 and the plane where the bottom of the outer cover 13 is located is greater than the distance D2 between the bottom of the spherical cup 121 and the plane where the bottom of the outer cover 13 is located, that is, the position of the air inlet pipe 131 is higher than the highest position of the spherical cup 121, the area around the spherical cup 121 is more quickly surrounded by nitrogen, rapidly reducing the oxygen content at the thermocouple inlet of the process tube 15 that is in contact with the spherical cup 121.

[0033] The distance between the rim of the ball cup 121 and the plane containing the bottom of the outer cover 13 is D3. The value of D3 ranges from 5mm to 7mm; in this embodiment, D3 is 5mm. In practical applications, the distance between the rim of the ball cup 121 and the stainless steel panel on the top of the machine is approximately 10mm. To facilitate installation and ensure that the outer cover 13 is filled with nitrogen, a 5mm clearance is left between the rim of the ball cup 121 and the stainless steel panel on the top of the machine.

[0034] In this embodiment, the air inlet pipe 131 is used to introduce nitrogen gas. Introducing nitrogen gas into the outer cover 13 so that the inner tube 12 is wrapped with nitrogen gas can reduce the oxygen content in the outer cover 13 and reduce the contact between the inner tube 12 and oxygen.

[0035] In this embodiment, the isolation tube 11, the inner tube 12, and the outer cover 13 are all made of quartz. Furthermore, the connecting tube 122 and the outer cover 13 are both made of transparent quartz.

[0036] like Figure 2 As shown, the region 111 of the isolation tube 11 closest to the ball bowl 121 is the first to come into contact with the cold process gas. In this embodiment, the material of the region 111 is set to be opaque quartz.

[0037] refer to Figures 1-2 The connecting pipe 122 is cylindrical in shape. One end of the connecting pipe 122 is sealed to the bottom of the ball bowl 121, and the other end of the connecting pipe 122 is sealed to the outer wall of the isolation pipe 11.

[0038] refer to Figure 2 The two ends of the connecting pipe 122 have the same cross-section perpendicular to the X-axis. In some embodiments, the shape of the cross-section perpendicular to the X-axis at both ends of the connecting pipe 122 is not exactly the same as the shape of the cross-section perpendicular to the X-axis at the middle part of the connecting pipe 122. For example, the shape of the connecting pipe 122 is hemispherical, and the cross-section perpendicular to the X-axis of each part of the connecting pipe 122 is different.

[0039] The connecting pipe 122 can also take on various shapes. For example, in one embodiment, the connecting pipe 122 is a stepped pipe, and in another embodiment, the connecting pipe 122 is formed by splicing two pipe sections.

[0040] The outer cover 13 is cylindrical in shape, and correspondingly, the cross-sectional areas of the top and bottom of the outer cover 13 are the same. In order to ensure that the gas inside the outer cover 13 encloses the spherical bowl 121, the cross-section of the outer cover 13 perpendicular to the X-axis is circular.

[0041] In some embodiments, the cross-sectional areas of the top and bottom of the outer cover 13 are different. For example, the outer cover 13 is bell-shaped, and the cross-sectional area of ​​the top of the outer cover 13 perpendicular to the X-axis is smaller than the cross-sectional area of ​​the bottom of the outer cover 13 perpendicular to the X-axis.

[0042] In this embodiment, the inner tube 12 and the outer cover 13 are integrally formed. Sealing them with the isolation tube 11 provides better sealing performance, thereby reducing the leakage rate at the process tube thermocouple inlet. In another embodiment, the inner tube 12 and the outer cover 13 are separately formed and then separately sealed with the isolation tube 11. During the connection process, it is ensured that the inner tube 12 and the isolation tube 11 are sealed together, and that the outer cover 13 and the isolation tube 11 are also sealed together.

[0043] Continue to refer to Figure 2The difference between the outer diameter of the rim of the spherical bowl 121 and the inner diameter of the outer cover 13 is D4, where D4 is less than 5 mm. Correspondingly, the internal volume of the outer cover 13 is smaller, thus requiring a smaller nitrogen flow rate. For example, in this embodiment, the outer diameter of the rim of the spherical bowl 121 is 37 mm, and the inner diameter of the outer cover 13 is 40 mm, meaning D4 is 3 mm, and the required nitrogen flow rate is 0.5 liters per minute.

[0044] refer to Figure 3 When the thermocouple sheath is connected to the process tube of the diffusion furnace, the thermocouple sheath is placed vertically, the isolation tube 11 is inserted into the process tube 15, and the inner wall of the spherical cup 121 is in direct contact with the spherical inlet end 151 of the process tube 15 to achieve a seal. Thermocouple 10 is inserted into the isolation tube 11. The thermocouple 10 includes a thermocouple wire and a ceramic thin tube, with the thermocouple wire disposed inside the ceramic thin tube.

[0045] This embodiment describes a high-temperature furnace tube application scenario. The process tube 15 is made of silicon carbide. The spherical inlet end 151 of the process tube 15 has a temperature greater than 600 degrees Celsius during the process, making it impossible to seal with a sealing ring.

[0046] refer to Figure 3 The inner wall of the ball cup 121 is frosted, and the spherical inlet end 151 of the process tube 15 is in direct contact with the inner wall of the ball cup 121. The frosting can achieve a seal.

[0047] Continue to refer to Figure 2 The isolation tube 11 has a round rod 14 at one end, and the process tube 15 has an insertion hole (not shown) inside. The end of the round rod 14 can be inserted into the insertion hole to fix the isolation tube 11 to the process tube 15. The round rod 14 is made of quartz.

[0048] Nitrogen gas is introduced into the outer cover 13 through the air inlet pipe 131, forming a nitrogen environment around the thermocouple spherical inlet end 151 of the process tube 15. This effectively prevents atmospheric oxygen from entering the process tube 15, improves the sealing performance of the thermocouple spherical inlet end 151 of the process tube 15, reduces the leakage rate, and thus reduces the problem of poor wafer uniformity caused by a high leakage rate. This improves the stability of the machine and ensures the quality of the product.

[0049] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion. The various embodiments in this specification are described in a related manner, and similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments.

[0050] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of protection of this utility model. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications should also be considered within the scope of protection of this utility model.

Claims

1. A thermocouple sheath, characterized in that, include: An isolation tube, which is a cylindrical tube, is used to house a thermocouple; An inner tube, the inner tube including a ball-shaped cup, the isolation tube extending through the bottom of the ball-shaped cup; An outer cover is disposed outside the inner tube. The side of the outer cover near the bottom of the spherical bowl is the top of the cover, and the side of the outer cover near the mouth of the spherical bowl is the bottom of the cover. The top of the cover is sealed to the outer wall of the isolation tube, and the bottom of the cover is open. An air inlet pipe is provided on the surface of the outer cover.

2. The thermocouple sheath according to claim 1, characterized in that, The inner tube also includes a connecting tube, which is disposed at the bottom of the spherical bowl, with its two ends respectively in close contact with the outer wall of the isolation tube and the bottom of the spherical bowl.

3. The thermocouple sheath according to claim 2, characterized in that, Both the connecting pipe and the outer cover are cylindrical in shape.

4. The thermocouple sheath according to claim 1, characterized in that, The distance between the air inlet pipe and the plane where the bottom of the cover is located is greater than the distance between the bottom of the bowl and the plane where the bottom of the cover is located. The air inlet pipe is used to introduce nitrogen gas.

5. The thermocouple sheath according to claim 1, characterized in that, The materials of the isolation tube, the inner tube, and the outer cover are all quartz.

6. The thermocouple sheath according to claim 1, characterized in that, The cross-sectional areas of the top and bottom of the outer cover are different.

7. The thermocouple sheath according to claim 1, characterized in that, The inner tube and the outer cover are integrally formed.

8. The thermocouple sheath according to claim 1, characterized in that, When the thermocouple sheath is connected to the process tube, the isolation tube is inserted into the process tube, and the inner wall of the ball cup directly contacts the spherical inlet end of the process tube to achieve a seal.

9. The thermocouple sheath according to claim 8, characterized in that, The other end of the isolation tube is provided with a round rod, and the inside of the process tube is provided with an insertion hole. The end of the round rod can be inserted into the insertion hole to fix the isolation tube to the process tube.

10. The thermocouple sheath according to claim 1, characterized in that, The inner wall of the spherical bowl has a frosted surface.

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