Coil structure for shielding radio frequency electromagnetic field of gas source furnace

Abstract

According to the ingenious coil structure for shielding the radio frequency electromagnetic field of the gas source furnace, the mode that the multiple layers of coils surround the cavity is adopted, the innermost layer of coil provides the radio frequency field, the outer layer of coil forms a shielding layer to prevent the electromagnetic field from leaking outwards, mutual interference between the radio frequency electromagnetic field and the environment can be prevented, the center cooling water pipe is arranged in the coil, and the cooling effect is good. Compared with an existing mode of wrapping by adopting a'metal cage 'structure, the method disclosed by the invention is beneficial to reducing the cost, reducing the weight and accelerating heat dissipation.

Description

Technical Field

[0001] The invention belongs to the technical field of molecular beam epitaxy equipment, and in particular relates to a coil structure for shielding a radio frequency electromagnetic field of a gas source furnace. Background Art

[0002] Molecular beam epitaxy technology or CVD technology is widely used in the growth of semiconductor thin film materials, among which the gas source furnace is a very important part. It can provide a high-purity activation gas flow and provide raw materials for the preparation of epitaxial units. When the gas source furnace is working, it needs to use a radio frequency field to excite atoms, thereby converting them into ions and activating atoms in molecules. However, when the radio frequency passes through the coil, the metal near the coil will be inductively heated, making the temperature of the surrounding metal uncontrollable. In addition, the coil of the gas source furnace is equivalent to an antenna. When wireless radio frequency signals are detected, it will interfere with various electronic devices around it. At the same time, external equipment will in turn interfere with the generation of the radio frequency field, thereby affecting the normal operation of the gas source furnace. In order to ensure the working stability and accuracy of the gas source furnace, measures must be taken to shield the electromagnetic field of the radio frequency coil.

[0003] The RF shielding of the gas source furnace in molecular beam epitaxy is a protective measure to prevent the RF electromagnetic field from coupling with the surrounding environment. This shielding is usually made of metal or alloy materials, which can effectively isolate the influence of the RF electromagnetic field on the outside. On the one hand, it can prevent the external metal parts from being heated by RF induction through shielding, and at the same time, it can also avoid mutual interference between electromagnetic fields. In existing molecular beam epitaxy equipment, the RF shielding is formed by surrounding the gas source furnace with metal or alloy materials to form a "cage"-like structure, thereby blocking the interference of external electromagnetic waves. However, this method usually uses a large amount of metal or alloy materials, is costly, and is heavy. Summary of the invention

[0004] In order to solve the problems of the prior art, a simple gas source furnace RF shielding method is proposed on the basis of ensuring the RF shielding of the gas source furnace. The present invention adopts a multi-layer coil to surround the gas pipeline. The innermost coil provides a coupled RF field, and the outer coil forms a shielding layer to prevent external electromagnetic interference.

[0005] The coil structure for shielding the radio frequency electromagnetic field of a gas source furnace provided by the present invention is characterized in that the gas chamber (3) of the gas source furnace is surrounded by a multi-layer radio frequency coil (2) on the outside, and a coil annular shielding cover plate (1) is provided on the top of the multi-layer radio frequency coil (2). A chamber orifice plate (101) is installed on the top of the gas chamber (3) to facilitate gas outflow. A shell side tube (102) is provided on the outside of the multi-layer radio frequency coil (2). The multi-layer radio frequency coil (2) includes an inner layer surrounding coil (201) and an outer layer surrounding coil (202). The inner layer surrounding coil (201) and the outer layer surrounding coil (202) are not in contact with each other, the coils of the inner layer surrounding coil (201) are not in contact with each other, and the coils of the outer layer surrounding coil (202) are wound in close contact in sequence. In this way, the outer layer surrounding coil (202) and the shielding annular cover plate (1) form a shielding structure to shield the internal electromagnetic field from leaking out. At the same time, the inner layer surrounding coil (201) and the outer layer surrounding coil (202) are hollow tubes, and cooling water pipes (204) are installed in the hollow tubes. In this way, the heat of the induction heating of the metal material by the electromagnetic field is removed by water cooling, thereby preventing the metal material of the outer layer surrounding coil (202) from heating up.

[0006] The number of coil layers of the multi-layer radio frequency coil (2) is at least 2. Optionally, conductive solder (203) is used to fill and weld between the coils of the outer surrounding coil (202) to form a reliable shielding layer.

[0007] The advantage of the present invention is that it uses a multi-layer coil to surround the cavity. The innermost coil provides the radio frequency field, and the outer coil forms a shielding layer to prevent the electromagnetic field from leaking out, which can prevent the radio frequency electromagnetic field from interfering with the environment. A central cooling water pipe is set inside the coil to help take away heat. Compared with the existing "metal cage" structure wrapping method, the present invention method helps to reduce costs, reduce weight and speed up heat dissipation. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a schematic structural diagram of the present invention.

[0009] Description of reference numerals: 1 coil annular shielding cover plate, 2 multi-layer radio frequency coil, 3 gas chamber, 101 chamber orifice plate, 102 shell side tube, 201 inner layer surrounding coil, 202 outer layer surrounding coil, 203 conductive solder, 204 cooling water pipe Implementation Example

[0010] like Figure 1The coil structure for shielding the radio frequency electromagnetic field of the gas source furnace shown in the figure, the multi-layer radio frequency coil 2 is tightly wound on the gas chamber 3 of the gas source furnace in the molecular beam epitaxy equipment in a multi-layer winding manner, wherein the inner layer surrounding coil 201 surrounds the gas chamber 3, and the coils in the same layer do not touch each other, and a certain winding spacing is retained. The outer layer surrounding coil 202 surrounds the innermost layer surrounding coil 201, and the outer layer surrounding coil 202 does not touch the inner layer surrounding coil 201, and a certain spacing is maintained. The coils in the same layer of the outer layer surrounding coil 202 are wound in close contact with each other. To avoid poor contact, the conductive solder 203 can be used to weld the coils in the same layer of the outermost layer surrounding coil 202 to ensure good contact. The outer layer surrounding coil 201 is wrapped with a metal shell side tube 102, and a coil shielding annular cover plate 1 is provided on the top of the multi-layer radio frequency coil 2. The outer layer surrounding coil 202 and the inner layer surrounding coil 201 are hollow tubes, and a cooling water pipe 204 is installed inside.

[0011] In the working mode, the multi-layer RF coil 2 is connected to the RF power supply, the inner layer surrounding coil 201 is coupled to the RF field, and the gas in the gas chamber is excited to form plasma, and the plasma is output to the outside through the chamber orifice 101. The outer layer surrounding coil 202 is in close contact with the same layer coil, and is welded by conductive solder 203 to form a complete metal isolation cylinder to shield the internal electromagnetic field from leaking out. The central water pipe 204 of the coil is connected to the cold water system to take away the heat generated by the induction heating during the working process of the outer layer surrounding coil 202 and the inner layer surrounding coil 201. In this way, the structure outside the outer layer surrounding coil is protected from being heated by induction heating.

[0012] The above embodiments mainly illustrate the coil structure of the radio frequency electromagnetic field of the shielding gas source furnace proposed by the present invention. Although only one embodiment of the present invention is described, the present invention can be implemented in many other ways without departing from its purpose and scope. Therefore, it should be understood that the above embodiments are not limited to the present invention, and all modifications and replacements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A coil structure for shielding a radio frequency electromagnetic field of a gas source furnace, characterized in that: The gas chamber (3) of the gas source furnace is surrounded by a multi-layer radio frequency coil (2) on the outside, a coil annular shielding cover plate (1) is provided on the top of the multi-layer radio frequency coil (2), a chamber orifice plate (101) is installed on the top of the gas chamber (3), and the multi-layer radio frequency coil (2) is provided with a shell side tube (102) on the outside, comprising an inner layer surrounding coil (201) and an outer layer surrounding coil (202), wherein the inner layer surrounding coil (201) and the outer layer surrounding coil (202) are not in contact with each other, the coils of the inner layer surrounding coil (201) are not in contact with each other, and the coils of the outer layer surrounding coil (202) are wound in close contact in sequence, and the coils of the inner layer surrounding coil (201) and the outer layer surrounding coil (202) are hollow tubes, and cooling water pipes (204) are arranged in the hollow tubes.

2. The coil structure for shielding the radio frequency electromagnetic field of a gas source furnace according to claim 1, characterized in that: The multi-layer radio frequency coil (2) has at least two coil layers.

3. The coil structure for shielding the radio frequency electromagnetic field of a gas source furnace according to claim 1, characterized in that: Conductive solder (203) is used to perform filling welding between the coils of the outer layer surrounding coil (202) to achieve close contact winding.

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