Novel MPCVD butterfly-shaped lower cavity gas flow equalizing structure
By designing multiple exhaust pipes and buffer chambers at the bottom of the MPCVD chamber and optimizing the position and inner diameter of the exhaust pipes, the problems of uneven deposition and uneven temperature field caused by unidirectional gas flow were solved, resulting in a more uniform gas distribution and higher crystal quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHENYANG YINGXIN SEMICONDUCTOR TECHNOLOGY CO LTD
- Filing Date
- 2025-05-15
- Publication Date
- 2026-04-21
AI Technical Summary
Traditional MPCVD chamber design results in unidirectional gas flow, leading to uneven deposition and temperature field on the substrate. Although existing improved designs have solved the problem of gas not being able to pass through the central substrate, uneven deposition still exists.
Multiple exhaust pipes and buffer chambers are designed at the bottom of the lower cavity. The exhaust pipes are distributed in a circle with the buffer chamber axis as the center, and the inner diameter gradually increases. The position and number of exhaust pipes are optimized through CFD simulation, and the buffer chambers are increased to balance the gas flow, reduce the airflow impact, and achieve uniform gas discharge.
It significantly improves the uniformity of deposition thickness, enhances crystal quality, optimizes temperature field uniformity, reduces crystal growth defects during deposition, and improves equipment performance and production efficiency.
Smart Images
Figure CN224148174U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of novel MPCVD butterfly-shaped lower cavity gas flow equalization structure, specifically the lower cavity gas flow equalization structure of MPCVD (microwave plasma chemical vapor deposition) equipment. Background Technology
[0002] Traditional MPCVD lower chamber designs typically only have one vent at the bottom, resulting in gas flow primarily unidirectionally exiting along the chamber sidewalls under vacuum conditions. This design presents the following problems: 1. Deposition non-uniformity: Gas cannot pass through the central stage, leading to uneven substrate deposition thickness on the stage. 2. Temperature field non-uniformity: The plasma fireball within the chamber exhibits eccentricity due to gas eccentric exit, causing uneven temperature field distribution on the stage. To address this issue, existing vent designs use four vents evenly distributed below the lower chamber. While this solves the problem of gas not passing through the central stage, it still fails to resolve the issue of uneven gas deposition, and this vent configuration increases space occupancy. Utility Model Content
[0003] To address the aforementioned problems, specifically those raised in the background section, this invention proposes a novel MPCVD butterfly-shaped lower cavity gas flow equalization structure, comprising an upper cavity, a lower cavity, an air inlet, a central base, and an exhaust port. The upper cavity is mounted on the lower cavity via a sealing ring. The central base is located within the upper cavity. The air inlet is positioned above the upper cavity, and the exhaust port is positioned below the lower cavity. Multiple exhaust pipes are disposed below the lower cavity. A hollow buffer cavity is positioned above the exhaust port, and both ends of the exhaust pipes are connected to the interior of the buffer cavity and the interior of the upper cavity, respectively.
[0004] A further feature of this invention is that the buffer cavity is configured as a ring-shaped hollow structure.
[0005] A further feature of this invention is that the plurality of exhaust pipes are arranged in a circular pattern on the buffer cavity with the axis of the buffer cavity as the center.
[0006] A further feature of this invention is that the exhaust pipe is distributed in a C-shape around the axis of the buffer chamber in the area not directly above the exhaust port.
[0007] A further feature of this invention is that the inner diameter of the exhaust pipes closest to and farthest from the exhaust port gradually increases.
[0008] The beneficial technical effects of this invention are as follows: Multiple uniformly distributed exhaust pipes and buffer chambers are designed at the bottom of the lower cavity to achieve uniform gas discharge. Through computational fluid dynamics (CFD) simulation, the number, inner diameter, and position of the exhaust pipes are optimized to ensure uniform gas flow within the cavity, significantly improving the uniformity of the deposition thickness, enhancing the quality of the crystals on the substrate, optimizing the symmetry of the plasma fireball, ensuring the uniformity of the temperature field during the deposition process, reducing crystal growth defects caused by uneven gas distribution during the deposition process, improving the overall performance and production efficiency of the equipment, and adding a gas buffer chamber to balance the gas flow. The design of the buffer chamber effectively reduces airflow impact and gas flow instability, which helps to achieve uniform gas distribution within the upper cavity. Attached Figure Description
[0009] Figure 1 A schematic diagram of the overall structure of this solution is shown.
[0010] Figure 2 A top view of the exhaust pipe structure is shown.
[0011] Figure 3 A top view of the internal structure of the buffer cavity is shown.
[0012] Figure 4 A front view of the existing butterfly cavity airflow structure is shown.
[0013] Figure 5 A left view of an existing butterfly-shaped cavity airflow structure is shown.
[0014] Figure 6 The simulation diagram of the airflow effect of this scheme is shown.
[0015] Figure 7 The simulation diagram of the airflow effect of the existing butterfly cavity is shown.
[0016] The attached diagram is labeled as follows: 1. Upper cavity, 2. Lower cavity, 3. Air inlet, 4. Central base, 5. Exhaust pipe, 6. Buffer chamber, 7. Exhaust port. Detailed Implementation
[0017] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.
[0018] This invention proposes a novel MPCVD butterfly-shaped lower cavity gas flow equalization structure. Gas enters the cavity through the inlet 3, deposits on the central base 4 to form a plasma fireball, and is then extracted by the exhaust port 7 along the exhaust pipe 5 and the buffer cavity 6, so that the exhaust pipe 5 is evenly distributed in a circle to achieve uniform gas discharge.
[0019] Through computational fluid dynamics (CFD) simulation, the number, inner diameter, and position of the exhaust pipes 5 were optimized. The exhaust pipes 5 were uniformly distributed in a C-shape, with the notch of the C-shape positioned directly above the exhaust port 7. The inner diameter of the exhaust pipes 5, from closest to farthest from the exhaust port 7, was gradually increased to ensure that the negative pressure generated below each exhaust pipe 5 was similar. A gas buffer chamber 6 was added to balance the gas flow. The design of the buffer chamber effectively reduced airflow impact and gas flow instability, contributing to a uniform gas distribution within the upper chamber. The simulation effect of the airflow distribution in this scheme is shown in the figure below. Figure 6 As shown, a circular distribution is formed, proving that the airflow distribution is uniform. The existing butterfly-shaped cavity has four exhaust ports, which are evenly distributed below the lower cavity. The simulation effect of the airflow distribution is shown in the figure. Figure 7 As shown, the airflow is not distributed in a circular pattern, indicating that the airflow distribution is not uniform.
[0020] Although the present invention has been described with reference to preferred embodiments, various modifications can be made to it and components can be replaced with equivalents without departing from the scope of the present invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.
[0021] In the description of this utility model, terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," which indicate direction or positional relationships, are based on the direction or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0022] Furthermore, it should be noted that, in the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0023] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to those processes, articles, or apparatus / devices.
[0024] The technical solution of this utility model has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the protection scope of this utility model is obviously not limited to these specific embodiments. Without departing from the principle of this utility model, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of this utility model.
Claims
1. A novel MPCVD butterfly-shaped lower cavity gas flow equalization structure, comprising an upper cavity (1), a lower cavity (2), an air inlet (3), a central base (4), and an exhaust port (7), wherein the upper cavity (1) is mounted on the lower cavity (2) via a sealing ring, the central base (4) is disposed in the upper cavity (1), the air inlet (3) is disposed above the upper cavity (1), and the exhaust port (7) is disposed below the lower cavity (2), characterized in that: Multiple exhaust pipes (5) are provided below the lower cavity (2), and a hollow buffer cavity (6) is provided above the exhaust port (7). The two ends of the exhaust pipes (5) are respectively connected to the inside of the buffer cavity (6) and the inside of the upper cavity (1).
2. A novel MPCVD gas flow uniformity structure of a butterfly-shaped lower cavity according to claim 1, characterized in that: The buffer cavity (6) is configured as a ring-shaped hollow structure.
3. A novel MPCVD gas flow uniformity structure of a butterfly-shaped lower cavity according to claim 2, characterized in that: Multiple exhaust pipes (5) are arranged in a circular pattern on the buffer chamber (6) with the axis of the buffer chamber (6) as the center.
4. The novel MPCVD gas flow uniform structure of the butterfly-shaped lower cavity according to claim 2, characterized in that: The exhaust pipe (5) is distributed in a C-shape on the buffer cavity (6) in the area not directly above the exhaust port (7) with the axis of the buffer cavity (6) as the center.
5. A new type of MPCVD gas flow uniform structure of the butterfly-shaped lower cavity according to claim 3 or 4, characterized in that: The inner diameter of the exhaust pipe (5) from the closest to the exhaust port (7) to the farthest gradually increases.