A dust collector, plasma processing equipment and voltage regulation method

Abstract

The present invention provides a dust collector, plasma processing equipment and a voltage regulation method, comprising a gas pipeline connected to a chamber of a plasma equipment, a vacuum pump, a first annular frame located between the chamber and the vacuum pump, a plurality of blades connected to the side wall of the first frame via a first rotating shaft, the plurality of blades being arranged at a certain interval, and a voltage device for applying voltages of different polarities between two adjacent blades. During a plasma reaction, large dust particles generated during the reaction can be fixed on the energized blades by utilizing the principle of electrostatic adsorption. The inclined blades can also prevent particles in the gas pipeline from flowing back to the reaction chamber, and the inclination angle of the blades can be adjusted to adapt to the required gas pressure in the reaction chamber.

Description

Technical Field

[0001] The invention relates to the technical field of plasma etching, and in particular to a dust collector, plasma processing equipment and a voltage regulating method. Background Art

[0002] Micromachining of semiconductor substrates is a well-known technology that can be used to manufacture, for example, semiconductors, flat panel displays, light emitting diodes (LEDs), solar cells, etc. An important step in micromachining manufacturing is a plasma treatment process step, which is performed inside a reaction chamber, and a process gas is input into the reaction chamber. A radio frequency source is inductively and / or capacitively coupled to the reaction chamber to excite the process gas to form and maintain a plasma.

[0003] In order to ensure the etching rate in the reaction chamber, it is necessary to evacuate the reaction chamber to discharge the post-reaction gas and maintain the low-pressure environment inside the reaction chamber. At the same time, the evacuation process also serves the purpose of removing dust particles in real time, such as aging and wear of parts or byproducts produced by reactions. Many of these dust particles have a diameter of more than one micron. These particles cannot pass through the high-speed rotating vortex molecular pump rotor blades, so they will return to the reaction chamber from the gas pipeline with the fluctuation of the air flow, and easily fall on the surface of the substrate in the reaction, increasing the risk of adverse etching process. Even if an ordinary vacuum pump is used, the impact caused by the particle reflux cannot be completely discharged. Usually, in order to avoid the continuous accumulation of dust particles generated in the reaction, the chamber needs to be opened for cleaning after a single or multiple etchings are completed. However, it is impossible to reduce the movement of dust particles in the reaction chamber before opening the chamber. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a dust collector for chamber dust removal of plasma processing equipment, comprising:

[0005] a gas conduit connected to the chamber;

[0006] a vacuum pump for extracting gas from the chamber through the gas conduit;

[0007] A first ring-shaped frame, wherein the first frame is located between the chamber and the vacuum pump;

[0008] A plurality of blades connected to the side wall of the first frame via a first rotating shaft, wherein the plurality of blades are arranged at a certain interval;

[0009] A voltage device is used to apply voltages of different polarities between two adjacent blades.

[0010] Optionally, it further includes a circular second frame, the diameter of the second frame is smaller than the inner diameter of the first frame, and the plurality of blades are rotatably connected to the second frame.

[0011] Optionally, the outer side wall of the second frame has holes arranged at intervals, the blade is triangular, the short side of the blade is connected to the inner side wall of the first frame through a rotating shaft, and the acute angle of the blade relative to the short side rotates in coordination with the hole.

[0012] Optionally, the blade is rectangular, one short side of the blade is connected to the inner wall of the first frame through the first rotating shaft, and the other short side at the opposite position is rotatably connected to the outer wall of the second frame through the second rotating shaft.

[0013] Optionally, it further includes a first rotating ring, the inner diameter of which is larger than the inner diameter of the first frame, and one side of which has a gear track, the first rotating shaft passes through the side wall of the first frame and is fixedly connected to the gear, and the gear moves in coordination with the gear track of the first rotating ring. Optionally, it further includes a second rotating ring, the inner diameter of which is larger than the inner diameter of the first frame, and one side of which has a gear track, and two adjacent gears move in coordination with the gear tracks of the first rotating ring and the second rotating ring, respectively.

[0014] Optionally, the first rotating ring, the second rotating ring, the first rotating shaft and the gear are made of conductive materials, and the first frame is made of dielectric material.

[0015] Optionally, the first rotating ring and the second rotating ring are coaxially arranged with the first frame and are located between two adjacent gears. The first rotating ring and the second rotating ring are connected to the voltage device and have opposite polarities.

[0016] Optionally, the first rotating ring and the second rotating ring are coaxially arranged with the first frame and are located on both sides of the gear. The first rotating ring and the second rotating ring are connected to the voltage device and have opposite polarities.

[0017] Optionally, gear teeth are arranged on a part of the circumference of the gear, and gear teeth are not arranged on the remaining part.

[0018] Optionally, the first frame is provided with a flange for fixedly connecting with the plasma equipment.

[0019] Furthermore, the present invention also discloses a plasma processing device, comprising any one of the dust collectors described above.

[0020] Furthermore, the present invention also discloses a method for regulating the voltage of a plasma processing device, comprising the following steps:

[0021] step:

[0022] Setting the blades in any of the above-mentioned dust collectors to an inclination angle;

[0023] Extracting gas from a chamber of a plasma processing device by a vacuum pump and measuring a range of gas pressure variation;

[0024] When the minimum air pressure value is less than the expected air pressure value, the inclination angle of the blade can be increased;

[0025] When the minimum air pressure value is greater than the expected air pressure value, the inclination angle of the blade may be reduced and the air pressure variation range may continue to be measured.

[0026] The advantages of the present invention are as follows: the present invention provides a dust collector which can, during a plasma reaction, use the principle of electrostatic adsorption to fix large dust particles generated during the reaction process on energized blades during the extraction process, thereby preventing the large dust particles from moving disorderly inside the reaction chamber, causing substrate particle contamination, and affecting the yield of semiconductor production. The inclined blades can also block particles in the gas pipeline from flowing back into the reaction chamber. In addition, the present invention also provides a pressure regulating method, which can achieve a balance between blocking particles and maintaining the extraction flow rate by adjusting the inclination angle of the blades, so as to adapt to the gas pressure required by different reaction processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 A schematic structural diagram of a plasma processing device is shown;

[0029] Figure 2 A schematic structural diagram of a first embodiment of a dust collector is shown;

[0030] Figure 3 A schematic diagram of the enlarged structure of the second frame is shown;

[0031] Figure 4 A schematic diagram showing the structure of a square blade is shown;

[0032] Figure 5 A partial structural schematic diagram of a second embodiment of a dust collector is shown;

[0033] Figure 6 A schematic structural diagram of a third embodiment of a dust collector is shown;

[0034] Figure 7 A schematic structural diagram of a fourth embodiment of a dust collector is shown. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Embodiment 1

[0037] like Figure 1 A plasma processing device is shown, including a chamber 100 for generating plasma. An air inlet nozzle is usually arranged at the upper part of the chamber to transport reaction gas. A base is also arranged inside the chamber to support a substrate. A vacuum pump 400 is connected to the bottom of the chamber 100 through a gas pipeline 300. The connection position of the gas pipeline 300 and the chamber 100 is not limited to the bottom in the figure. In some embodiments, the gas pipeline 300 can also be connected to one side of the chamber 100. The vacuum pump 400 used is usually a vortex molecular pump, which maintains the low pressure in the chamber 100 by pumping air, and cooperates with the air inlet nozzle to form a gas circulation inside the chamber 100.

[0038] The dust collector of the present invention is located between the chamber 100 and the vacuum pump 400, and can be located at any position on the gas pipeline 300. In a preferred embodiment, the dust collector is fixed at the gas inlet of the gas pipeline 300 through a flange 201 and is arranged parallel to the bottom surface of the chamber 100. Figure 2As shown, the dust collector includes a first ring-shaped frame 200, the inner diameter of the ring can be the same as the inner diameter of the gas pipeline 300, and the flange fixed to the gas pipeline 300 can be set on the outer side wall of the first frame 200. A plurality of blades 212 are connected to the inner side wall of the first frame 200 through a first rotating shaft 211, and a certain interval is maintained between the plurality of blades 212. A single blade 212 can rotate along the first rotating shaft 211 to change the interval between the blades. A voltage device 500 is provided outside the chamber to apply a voltage to the dust collector so that the voltage polarities of two adjacent blades 212 are opposite. When plasma etching is performed, particles generated by frictional aging of parts or reaction byproducts flow from the top to the gas pipe 300 along with the gas in the chamber 100. Smaller particles can be discharged through the vacuum pump 400, while larger particles will adhere to the surface of the blades 212 due to electrostatic adsorption when passing through the blades 212 of the dust collector. In addition, the inclined blades 212 can also block the particles in the gas pipe 300 at the bottom of the dust collector. The two work together to prevent the particles from flowing back to the chamber and moving in a disorderly manner, which will have an adverse effect on the etching process. In some plasma etching processes, a lower chamber pressure is required, but the inclined blades block the airflow, limiting the further reduction of the chamber pressure. Therefore, the inclination angle of the blades 212 can be adjusted according to actual conditions to control the gas flow rate so that the chamber pressure can vary within a certain range. For example, when the blades 212 are completely vertical, the impact on the airflow is minimal. Figure 3 As shown, in some embodiments, a circular second frame 220 is also included. The second frame 220 can also be in the form of a ring. If blades 212 of the same size are used, the second frame 220 can be set at the center of the first frame 200. One end of the blade 212 is connected to the side wall of the first frame 200, and the other end is rotatably connected to the second frame 220. The second frame 200 can be made of dielectric material. Multiple blades 212 are rotatably connected to the second frame 200 and are electrically isolated from each other. In this way, it is only necessary to apply voltages of different polarities to the end where the blade 212 is connected to the first frame 200 to achieve the purpose of adsorbing dust particles. When the plasma etcher is regularly cleaned and maintained, the dust collector can be disassembled for cleaning and recycling. In some embodiments, the blade 212 is in the form of a triangle and is arranged around the first frame 200 and the second frame 220, wherein the short side of the blade 212 is connected to the first rotating shaft 211, and the acute angle corresponding to the short side is inserted into the hole 221 of the second frame 220 to achieve rotational connection, such as Figure 4 As shown, in other embodiments, the blade 212 is rectangular and can be rotatably connected to the first frame 200 in parallel with the first connecting shaft 211 and the second connecting shaft 213 , or can be arranged around the first frame 200 and the second frame 220 .

[0039] Embodiment 2

[0040] like Figure 6 As shown, the difference between this embodiment and the above embodiment is that it also includes a first rotating ring 230 whose inner diameter is larger than the outer diameter of the first outer frame 200, and one side of the first rotating ring 230 has a gear track. The first rotating shaft 211 passes through the side wall of the first frame 200 and is fixedly connected to the gear. The gear corresponding to each blade 212 can rotate in coordination with the gear track on the first rotating ring 230 nested on the outside of the first frame 200. In this way, all the blades can be driven to rotate in one direction by rotating the first rotating ring 230. In some embodiments, it also includes a second rotating ring 240 whose inner diameter is larger than the outer diameter of the first outer frame 200. One side of the second rotating ring 240 has a gear track, which can rotate in coordination with the gear corresponding to the blade 212. The first rotating ring 230 and the second rotating ring 240 are located on the upper and lower sides of the gear. The difference is that the axis of the first rotating shaft 211 is not on the same circumference, but the axis is spaced apart and located on two circumferences respectively, to ensure that the gear in contact with the first rotating ring 230 will not contact with the second rotating ring 240. Similarly, the gear in contact with the second rotating ring 240 will not contact with the first rotating ring 230. The first rotating ring 230, the second rotating ring 240, the gear and the first rotating shaft 211 are all conductors. In this way, by applying voltages of different polarities to the first rotating ring 230 and the second rotating ring 240, adjacent blades 212 can have different voltage polarities. At the same time, by rotating the two rotating rings, the inclination angle of the blade 212 can be changed, thereby changing the gas flow rate.

[0041] Embodiment 3

[0042] like Figure 5 As shown, the difference between this embodiment and the above embodiment is that the axis of each first rotating shaft 211 is located on the same circumference, but the gear fixedly connected to the first rotating shaft 211 has only a part of the teeth, and the two adjacent gears respectively rotate with the first rotating ring 230 and the second rotating ring 240 located on both sides of the gear, and will not contact different rotating rings. Compared with the first rotating shaft 211 not being on the same circumference, the blades 211 can be located at the same height, which ensures that the dust collector can be more compact without affecting the adsorption capacity of dust particles.

[0043] Embodiment 4

[0044] like Figure 7 As shown, the difference between this embodiment and the above embodiment is that the axis of each first rotating shaft 211 is located on a different circumference, the first rotating ring 230 and the second rotating shaft 240 are located between the gears, and the two rotating rings are electrically isolated. With this arrangement, it is easier to apply voltage between the two rotating rings, such as connecting the wires through the point isolation area between the two rotating rings, which can better hide the wires and avoid exposure.

[0045] Embodiment 5

[0046] like Figure 1 As shown, the present invention also discloses a plasma processing device, which can be an inductively coupled plasma processing device or a capacitively coupled plasma processing device, including a dust collector of any of the above embodiments for use in the exhaust system of the plasma processing device to reduce the contamination of dust particles on substrate processing in the reaction chamber.

[0047] Embodiment 6

[0048] The present invention also discloses a pressure regulating method for a plasma processing device equipped with a dust collector in the above embodiment, comprising step 1, setting a tilt angle of the blade 212 in the dust collector, which can be achieved by synchronously rotating a rotating ring; step 2, extracting air from the chamber of the plasma processing device by a vacuum pump, and measuring the pressure variation range; step 3, comparing the actually measured pressure variation range with the expected plasma reaction pressure. Due to the blocking effect of the blade 212, there may be a situation where the minimum value of the pressure variation range is less than the expected pressure value. At this time, the tilt angle of the blade 212 is increased to make the blade 212 closer to vertical, which is more conducive to airflow. If the minimum value of the pressure variation range is greater than the expected pressure value, the tilt angle of the blade 212 can be reduced to make the blade 212 closer to horizontal, which is more conducive to blocking the dust particles from flowing back; then repeat step 2 until a balance is reached between the pressure variation range and the dust particles blocked. In some embodiments, a change curve can also be drawn according to the angle change of the blade and the pressure range. Before the subsequent reaction, the pressure variation range is fixed according to the curve, and then the pressure value is fine-tuned according to the pendulum valve.

[0049] The dust collector disclosed in the present invention is not limited to being applied to the plasma processing equipment of the above two embodiments, but can also be applied to other plasma processing equipment, which will not be described in detail here.

[0050] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A dust collector for chamber dust removal of plasma processing equipment, characterized in that: include: a gas conduit connected to the chamber; a vacuum pump for extracting gas from the chamber through the gas conduit; A first ring-shaped frame, wherein the first frame is located between the chamber and the vacuum pump; A plurality of blades connected to the side wall of the first frame via a first rotating shaft, wherein the plurality of blades are arranged at a certain interval; A first rotating ring, one side of which has a gear track, the first rotating shaft passes through the side wall of the first frame and is fixedly connected to the gear, and the gear moves in coordination with the gear track of the first rotating ring; A second rotating ring, one side of which has a gear track, and two adjacent gears respectively cooperate with the gear tracks of the first rotating ring and the second rotating ring to move; A voltage device is electrically connected to the first rotating ring and the second rotating ring respectively, and is used to apply voltages of different polarities between two adjacent blades.

2. The dust collector according to claim 1, characterized in that: It also includes a circular second frame, the diameter of the second frame is smaller than the inner diameter of the first frame, and the plurality of blades are rotatably connected to the second frame.

3. The dust collector according to claim 2, characterized in that: The outer side wall of the second frame has holes arranged at intervals, the blade is triangular, the short side of the blade is connected to the inner side wall of the first frame through a rotating shaft, and the acute angle of the blade relative to the short side rotates in coordination with the hole.

4. The dust collector according to claim 2, characterized in that: The blade is rectangular, one short side of the blade is connected to the inner wall of the first frame through the first rotating shaft, and the other short side at the opposite position is rotatably connected to the outer wall of the second frame through the second rotating shaft.

5. The dust collector according to claim 1, characterized in that: An inner diameter of the first rotating ring is greater than an inner diameter of the first frame.

6. The dust collector according to claim 5, characterized in that: An inner diameter of the second rotating ring is greater than an inner diameter of the first frame.

7. The dust collector according to claim 6, characterized in that: The first rotating ring, the second rotating ring, the first rotating shaft and the gear are made of conductive materials, and the first frame is made of dielectric material.

8. The dust collector according to claim 7, characterized in that: The first rotating ring and the second rotating ring are coaxially arranged with the first frame and are located between two adjacent gears. The first rotating ring and the second rotating ring are connected to the voltage device and have opposite polarities.

9. The dust collector according to claim 7, characterized in that: The first rotating ring and the second rotating ring are coaxially arranged with the first frame and are located on both sides of the gear. The first rotating ring and the second rotating ring are connected to the voltage device and have opposite polarities.

10. The dust collector according to claim 9, characterized in that A portion of the circumference of the gear is provided with gear teeth, and the remaining portion is not provided with gear teeth.

11. The dust collector according to claim 1, characterized in that: The first frame is provided with a flange for fixedly connecting with the plasma equipment.

12. A plasma processing device, characterized in that: Comprising a dust collector as described in any one of claims 1-11.

13. A voltage regulating method for plasma processing equipment, characterized in that: The steps include: Setting a blade in the dust collector according to any one of claims 1 to 11 to an inclination angle; Extracting gas from a chamber of a plasma processing device by a vacuum pump and measuring a range of gas pressure variation; When the minimum air pressure value is less than the expected air pressure value, the inclination angle of the blade can be increased; When the minimum air pressure value is greater than the expected air pressure value, the inclination angle of the blade may be reduced and the air pressure variation range may continue to be measured.

Images