Continuous inductively coupled plasma-assisted chemical vapor deposition coating production line

Abstract

The invention discloses a continuous inductively coupled plasma-assisted chemical vapor deposition coating production line, which comprises a process cavity, a preheating cavity, a cooling cavity, a carrier plate, an ICP reaction source and a transmission mechanism, a radio frequency coupling coil of the ICP reaction source is arranged outside the process cavity, and a reaction gas is excited by an alternating induced magnetic field to discharge to generate plasma; an independent cooling and insulating structure is matched; and the preheating cavity, the processing cavity and the cooling cavity are respectively provided with an independent dry pump system and a functional module, so that continuous preheating, coating and cooling of the silicon wafer are realized. The plasma excitation electrode is arranged outside the vacuum chamber, electrode pollution can be avoided, the problem that a silicon wafer is damaged by plasma bombardment is reduced, and the device has the advantages of being good in film forming quality, high in deposition efficiency, long in equipment maintenance period and flexible in layout and is suitable for large-scale continuous production of the silicon nitride thin film of the solar cell.

Description

Technical Field

[0001] This invention relates to the field of vacuum coating equipment technology, and in particular to a continuous inductively coupled plasma-assisted chemical vapor deposition coating production line. Background Technology

[0002] Its main function is to passivate and reduce reflection on the silicon wafer surface, directly affecting the battery conversion efficiency. Currently, the most widely used industrial equipment is the capacitively coupled radio frequency PECVD (plasma-enhanced chemical vapor deposition) device. The process chamber of this device usually adopts a parallel layout of "upper electrode-lower electrode": the upper electrode serves as the process gas spray electrode, and the lower electrode serves as the ground electrode. The electrode discharge is excited by a 13.56MHz (RF) or 40 / 60MHz (VHF) radio frequency power supply, which ionizes the reactive gas to generate plasma, thereby depositing a thin film on the silicon wafer surface.

[0003] However, existing capacitively coupled PECVD devices have the following significant drawbacks:

[0004] Electrode contamination and silicon wafer damage: The electrodes are placed directly in the process cavity. During the discharge process, charged particles will directly bombard the electrode surface, causing the electrode material to fall off and contaminate the silicon wafer surface. At the same time, heavy ions in the plasma bombard the silicon wafer surface, causing more defects on the silicon wafer surface, affecting the film formation quality and battery conversion efficiency.

[0005] Limited process window and high maintenance costs: The discharge spacing between the upper and lower electrodes is fixed and it is difficult to adjust flexibly according to different process requirements, resulting in a narrow process window; and after long-term deposition, a thick film will accumulate on the inner wall of the process cavity and the surface of the electrodes, requiring frequent shutdowns for cleaning, which not only increases the time and economic costs of equipment maintenance, but also reduces production efficiency.

[0006] Production capacity layout and process interference issues: Existing equipment is limited by the structural design of "multiple electrodes sharing a single process cavity", which makes it difficult to achieve flexible layout for large area and large capacity. Moreover, when multiple electrodes work at the same time, mutual interference of process processes is likely to occur, which further affects the consistency of thin film deposition. Summary of the Invention

[0007] To address the aforementioned issues, this invention provides a continuous, low-pollution, and high-efficiency inductively coupled plasma-assisted chemical vapor deposition (ICP-CVD) production line, which solves the problems of electrode material contamination of silicon wafers, significant surface damage to silicon wafers, limited process windows, high equipment maintenance costs, and multi-electrode process interference found in existing capacitively coupled radio frequency PECVD devices.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a continuous inductively coupled plasma-assisted chemical vapor deposition (ICP-ACD) coating production line, comprising a process chamber, a preheating chamber, a cooling chamber, a carrier plate, an ICP reaction source, and a transfer mechanism. The process chamber is connected to the preheating chamber and the cooling chamber on both sides, respectively, with process valves for isolation and sealing at the connection points. A worktable is provided inside the process chamber, equipped with a lifting mechanism and a heating device. An ICP reaction source is installed in the center of the top, with gas inlets on both sides for introducing reaction gases, and a vacuum pipe for evacuation at the bottom. A preheating valve is located on the side of the preheating chamber away from the process chamber, and a heating module and a vacuum pipe are located inside. The cooling chamber... A cooling valve is located on the side of the cooling chamber away from the process chamber, and a cooling module and vacuum pipe are installed inside. The carrier plate moves between the preheating chamber, the process chamber, and the cooling chamber via a transmission mechanism. The ICP reaction source includes an RF window, an RF coupling coil, a coil fixing block, a coil fixing seat, a cover plate, a pressure block, a sealing ring, an RF power supply, a matching unit, and a capacitor. The RF window is sealed and fixed to the top of the process chamber by the sealing ring and the pressure block. Cooling circulating water is installed inside the RF coupling coil, which is fixed to the cover plate by the coil fixing block and the coil fixing seat. The RF power supply is electrically connected to the matching unit via a cable, one end of the RF coupling coil is connected to the matching unit, and the other end is grounded through a capacitor.

[0009] Furthermore, the preheating chamber, the process chamber, and the cooling chamber are each equipped with an independent dry pump system, which achieves independent vacuuming and pressure control through their respective vacuum pipelines.

[0010] The worktable inside the process chamber can be raised and lowered vertically to support the carrier plate and, in conjunction with the heating device, to precisely control the temperature of the silicon wafer.

[0011] Furthermore, the preheating valve of the preheating chamber and the cooling valve of the cooling chamber are respectively connected to the automated feeding and unloading system.

[0012] Furthermore, the radio frequency window is a high-strength quartz substrate.

[0013] Furthermore, the insulation of the cooling circulating water inside the radio frequency coupling coil is greater than 15 MΩ·cm.

[0014] Furthermore, the coil fixing block is made of snap-fit ​​insulating material, which fixes the radio frequency coupling coil and ensures the overall insulation of the ICP reaction source.

[0015] Furthermore, the transmission mechanism is a belt transmission mechanism that drives the carrier plate to move smoothly between the preheating chamber, the process chamber, and the cooling chamber.

[0016] As can be seen from the above description of the structure of the present invention, compared with the prior art, the present invention has the following advantages:

[0017] 1. The radio frequency coupling coil of the ICP reaction source of the present invention is placed outside the process cavity to avoid electrode material falling off and contaminating the silicon wafer, which can effectively reduce equipment maintenance time and improve production efficiency.

[0018] 2. Inductively coupled plasma is excited by an alternating magnetic field, avoiding the direct bombardment of the silicon wafer surface by charged particles in capacitive coupling, reducing silicon wafer surface defects, improving silicon wafer passivation effect, and further improving solar cell conversion efficiency.

[0019] 3. The preheating-processing-cooling continuous operation, combined with automated loading and unloading, greatly improves the production cycle. The independent dry pump system avoids interference between chambers. ICP can generate high-density plasma, resulting in a fast deposition rate, which is conducive to obtaining uniform, dense, high-quality films and ensuring film formation consistency.

[0020] 4. The independent vacuum system and modular three-chamber structure allow for flexible adjustment of process parameters according to production cycle and process requirements, expanding the process window, and providing a flexible layout that facilitates large-scale continuous production. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0023] Figure 2 for Figure 1 A magnified view of a portion of the ICP reaction source;

[0024] Figure 3 This is a schematic diagram of the principle of an ICP reaction source.

[0025] Explanation of the labels in the diagram:

[0026] 1. Process chamber; 11. Worktable; 12. Vacuum pipe; 13. Air inlet; 14. Process valve;

[0027] 2. Preheating chamber; 21. Preheating valve; 22. Heating module;

[0028] 3. Cooling chamber; 31. Cooling valve; 32. Cooling module;

[0029] 4. Carrier plate;

[0030] 5. ICP reaction source, 51. RF window, 52. RF coupling coil, 53. Coil fixing block, 54. Coil fixing base, 55. Cover plate, 56. Pressure block, 57. Sealing ring, 58. RF power supply, 59. Matching unit, 510. Capacitor;

[0031] 6. Transmission mechanism. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0033] Example

[0034] refer to Figures 1-3 A continuous inductively coupled plasma-assisted chemical vapor deposition (ICP-ACD) coating production line includes a process chamber 1, a preheating chamber 2, a cooling chamber 3, a carrier plate 4, an ICP reaction source 5, and a transfer mechanism 6. The process chamber 1 is connected to the preheating chamber 2 and the cooling chamber 3 on both sides, with process valves 14 for isolation and sealing at the connection points. A worktable 11 is located within the process chamber 1, equipped with a lifting mechanism and a heating device. The worktable 11 can be raised and lowered vertically to support the carrier plate 4 and, in conjunction with the heating device, precisely control the temperature of the silicon wafer. The ICP reaction source 5 is installed at the top center, with gas inlets 13 on both sides for introducing reaction gases, and a vacuum pipe 12 at the bottom for evacuation. The preheating chamber 2 has a preheating valve 21 on the side away from the process chamber 1, and contains a heating module 22 and a vacuum pipe 12. The cooling chamber 3 has a cooling valve 31 on the side away from the process chamber 1, and contains a cooling module 22. The module 32 is connected to the vacuum pipe 12; the carrier plate 4 moves between the preheating chamber 2, the process chamber 1, and the cooling chamber 3 via the transmission mechanism 6; the ICP reaction source 5 includes an RF window 51, an RF coupling coil 52, a coil fixing block 53, a coil fixing seat 54, a cover plate 55, a pressure block 56, a sealing ring 57, an RF power supply 58, a matching unit 59, and a capacitor 510; the RF window 51 is a high-strength quartz substrate, and the RF window 51 is sealed and fixed to the top of the process chamber 1 by the sealing ring 57 and the pressure block 56; the RF coupling coil 52 is equipped with cooling circulating water, and the insulation of the cooling circulating water in the RF coupling coil 52 is greater than 15MΩ·cm, and it is fixed to the cover plate 55 by the coil fixing block 53 and the coil fixing seat 54; the RF power supply 58 is electrically connected to the matching unit 59 via a cable, one end of the RF coupling coil 52 is connected to the matching unit 59, and the other end is grounded through the capacitor 510.

[0035] The preheating chamber 2, the process chamber 1, and the cooling chamber 3 are each equipped with an independent dry pump system, and each achieves independent vacuuming and pressure control through its respective vacuum pipeline 12.

[0036] The preheating valve 21 of the preheating chamber 2 and the cooling valve 31 of the cooling chamber 3 are respectively connected to the automated feeding and unloading system.

[0037] The coil fixing block 53 is a snap-fit ​​insulating material that fixes the radio frequency coupling coil 52 and ensures the overall insulation of the ICP reaction source 5.

[0038] The transmission mechanism 6 is a belt transmission mechanism that drives the carrier plate 4 to move smoothly between the preheating chamber 2, the process chamber 1, and the cooling chamber 3.

[0039] The specific operation process of the coating production line is as follows:

[0040] S1: Initial state control: Close the process valves 14 on both sides of the process chamber 1 and the cooling valves 31 of the cooling chamber 3, and evacuate the process chamber 1 and the cooling chamber 3 through the vacuum pipe 12 respectively;

[0041] S2: Preheating chamber loading and pretreatment: Open the preheating valve 21 of the preheating chamber 2, and send the carrier plate 4 containing silicon wafers into the designated position of the preheating chamber 2 through the transmission mechanism 6, and close the preheating valve 21; evacuate through the vacuum pipe 12 of the preheating chamber 2, and at the same time start the heating module 22 to preheat the chamber and silicon wafers.

[0042] S3: Carrier plate transfer to process chamber: When the vacuum level and temperature of the preheating chamber 2 and the process chamber 1 reach the process requirements and the pressure is balanced, open the process valve 14 on the left side of the process chamber 1, and send the carrier plate 4 into the designated position of the process chamber 1 through the transfer mechanism 6, and close the process valve 14; raise the worktable 11 to support the carrier plate 4, and continue to heat the silicon wafer through the heating device of the worktable 11, while the preheating chamber 2 breaks the vacuum and is ready for use;

[0043] S4: Plasma deposition: Reactive gas is introduced through the gas inlet 13 of the process cavity 1. After the conditions inside the cavity meet the process requirements, the RF power supply 58 is started. The RF power supply 58 transmits energy to the radio frequency coupling coil 52 through the matching unit 59. The energy is introduced into the process cavity 1 through the radio frequency window 51, which excites the reactive gas to discharge and generate plasma. The plasma is deposited on the silicon wafer surface to form a thin film.

[0044] S5: Carrier plate transferred to cooling chamber: After coating is completed, the worktable 11 is lowered to the initial position; when the pressure of the process chamber 1 and the cooling chamber 3 is balanced, the process valve 14 on the right side of the process chamber 1 is opened, and the carrier plate 4 is sent into the designated position of the cooling chamber 3 through the transfer mechanism 6, and the process valve 14 is closed; inert gas is introduced into the cooling chamber 3 for purging, and the cooling module 32 is started to cool the silicon wafer;

[0045] S6: Feeding and Circulation: When the temperature of the silicon wafer in the cooling chamber 3 drops to the set value, the vacuum in the cooling chamber 3 is broken, the cooling valve 31 is opened, and the carrier plate 4 is transported to the automated feeding system through the transmission mechanism 6; at the same time, the preheating chamber 2 repeats step S2 to feed the wafer and enters the next round of coating cycle.

[0046] In this invention, the radio frequency coupling coil of the ICP reaction source is placed outside the process chamber, avoiding electrode material shedding and contaminating the silicon wafer. This effectively reduces equipment maintenance time and improves production efficiency. The inductively coupled plasma is excited by an alternating magnetic field, avoiding direct bombardment of the silicon wafer surface by charged particles in capacitive coupling, reducing silicon wafer surface defects, improving silicon wafer passivation, and further improving solar cell conversion efficiency. The preheating-processing-cooling continuous operation, combined with automated loading and unloading, significantly increases the production cycle. The independent dry pump system avoids interference between chambers. ICP can generate high-density plasma with a fast deposition rate, which is conducive to obtaining uniform, dense, high-quality thin films and ensuring film formation consistency. The independent vacuum system and modular three-chamber structure allow for flexible adjustment of process parameters according to production cycle and process requirements, expanding the process window. The flexible layout facilitates large-scale continuous production.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A continuous inductively coupled plasma-assisted chemical vapor deposition (ICP-C) coating production line, characterized in that: The system includes a process chamber (1), a preheating chamber (2), a cooling chamber (3), a carrier plate (4), an ICP reaction source (5), and a transfer mechanism (6). The process chamber (1) is connected to the preheating chamber (2) and the cooling chamber (3) on both sides, and a process valve (14) for isolation and sealing is provided at the connection. A workbench (11) is provided inside the process chamber (1). The workbench (11) is equipped with a lifting mechanism and a heating device. An ICP reaction source (5) is installed in the middle of the top, and air inlets (13) for introducing reaction gas are provided on both sides. A vacuum pipe (12) for evacuation is provided at the bottom. A preheating valve (21) is provided on the side of the preheating chamber (2) away from the process chamber (1). A heating module (22) and a vacuum pipe (12) are provided inside the preheating chamber (2). A cooling valve (31) is provided on the side of the cooling chamber (3) away from the process chamber (1). A cooling module (32) and a vacuum pipe (12) are provided inside the cooling chamber (3). The carrier plate (6) 4) Moves between the preheating chamber (2), the process chamber (1), and the cooling chamber (3) via the transmission mechanism (6); The ICP reaction source (5) includes an RF window (51), an RF coupling coil (52), a coil fixing block (53), a coil fixing seat (54), a cover plate (55), a pressure block (56), a sealing ring (57), an RF power supply (58), a matching device (59), and a capacitor (510); The RF window (51) is sealed and fixed to the top of the process chamber (1) by the sealing ring (57) and the pressure block (56); The RF coupling coil (52) is provided with cooling circulating water and is fixed to the cover plate (55) by the coil fixing block (53) and the coil fixing seat (54); The RF power supply (58) is electrically connected to the matching device (59) via a cable, and one end of the RF coupling coil (52) is connected to the matching device (59), and the other end is grounded via the capacitor (510).

2. The continuous inductively coupled plasma-assisted chemical vapor deposition (CVD) coating production line according to claim 1, characterized in that, The preheating chamber (2), the process chamber (1), and the cooling chamber (3) are each equipped with an independent dry pump system, and achieve independent vacuuming and pressure control through their respective vacuum pipes (12).

3. The continuous inductively coupled plasma-assisted chemical vapor deposition (CVD) coating production line according to claim 1, characterized in that, The worktable (11) inside the process cavity (1) can be raised and lowered vertically to support the carrier plate (4) and to cooperate with the heating device to precisely control the temperature of the silicon wafer.

4. The continuous inductively coupled plasma-assisted chemical vapor deposition (CVD) coating production line according to claim 1, characterized in that, The preheating valve (21) of the preheating chamber (2) and the cooling valve (31) of the cooling chamber (3) are respectively connected to the automated feeding and unloading system.

5. The continuous inductively coupled plasma-assisted chemical vapor deposition (CVD) coating production line according to claim 1, characterized in that, The radio frequency window (51) is a high-strength quartz substrate.

6. The continuous inductively coupled plasma-assisted chemical vapor deposition (CVD) coating production line according to claim 1, characterized in that, The insulation of the cooling circulating water inside the radio frequency coupling coil (52) is greater than 15 MΩ·cm.

7. The continuous inductively coupled plasma-assisted chemical vapor deposition (CVD) coating production line according to claim 1, characterized in that, The coil fixing block (53) is a snap-fit ​​insulating material that fixes the radio frequency coupling coil (52) and ensures the overall insulation of the ICP reaction source (5).

8. The continuous inductively coupled plasma-assisted chemical vapor deposition (CVD) coating production line according to claim 1, characterized in that, The transmission mechanism (6) is a belt transmission mechanism that drives the carrier plate (4) to move smoothly between the preheating chamber (2), the process chamber (1), and the cooling chamber (3).

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