Plasma filtering device and filtering method

Abstract

The present invention relates to a plasma filtering device and a filtering method. The plasma filtering device comprises: a first passage and a second passage located within a main body of the plasma filtering device. A baffle is provided between the first passage and the second passage, and the baffle is provided with an opening with an adjustable opening. When the opening is closed, plasma, after being formed, diffuses upward in the first passage, passes over the top of the baffle, and then flows downward in the second passage. When the plasma diffuses upward in the first passage, part of the plasma collides with the sidewall of the first passage and is filtered and removed, thereby reducing the plasma density and alleviating damage to the substrate. When the opening is open, at least part of the plasma, after being formed in the first passage, can directly enter the second passage through the opening, thereby increasing the plasma density and improving the reaction rate.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and in particular to a plasma filtering device and a filtering method. Background Art

[0002] In the chip manufacturing process, plasma is used in many processes, such as plasma etching, plasma stripping, plasma thin film deposition, etc. Some process steps have strict requirements on ion damage. Excessive plasma density will lead to severe ion bombardment of the substrate and excessive accumulation of charge on the substrate, causing substrate breakdown damage. In contrast, some process steps require a high reaction rate, and the thin film on the substrate surface is stable and hard enough that ion bombardment will not damage the substrate. In this case, increasing the plasma density can increase the reaction activity and the reaction rate. Existing equipment cannot take into account the different plasma density requirements of different process steps. Summary of the Invention

[0003] Based on this, and in response to the above problems, the present invention provides a plasma filtering device and a filtering method.

[0004] The present invention provides a plasma filter device, comprising: a first passage and a second passage located within a main body of the plasma filter device; a baffle disposed between the first and second passages; and an opening with an adjustable opening on the baffle. When the opening is closed, plasma, after being formed, diffuses upward within the first passage, passes over the top of the baffle, and then flows downward within the second passage, thereby reducing ion damage and a reaction rate. When the opening is open, at least a portion of the plasma, after being formed within the first passage, directly enters the second passage through the opening, thereby increasing ion damage and a reaction rate. The baffle comprises an upper baffle and a lower baffle, with a gap between the upper and lower baffles forming the opening. The device also comprises a lifting device connected to the upper baffle via a lifting member. The lifting device raises and lowers the lifting member to adjust the relative position between the upper and lower baffles, thereby adjusting the opening. When the upper and lower baffles are closed, the opening is closed; when the upper and lower baffles are separated, the opening is opened.

[0005] The plasma filtering device can switch between high and low plasma density. When the opening is closed, plasma, after being formed, diffuses upward within the first passage, passes over the top of the baffle, and then flows downward within the second passage. When the plasma diffuses upward within the first passage, part of the plasma collides with the sidewalls of the first passage and is filtered and removed, thereby reducing the plasma density and alleviating damage to the substrate. When the opening is open, at least part of the plasma, after being formed within the first passage, can directly enter the second passage through the opening, thereby increasing the plasma density and improving the reaction rate.

[0006] In one embodiment, a control module is further included to control the opening of the opening. When the opening is closed, the degree of ion damage is reduced and the reaction rate is reduced; when the opening is open, the degree of ion damage is increased and the reaction rate is increased. The opening opening can be controlled in real time according to demand, switching between low substrate damage and high reaction rate at any time according to demand.

[0007] In one embodiment, a plasma density detection module is further included to detect a plasma density signal within the reaction chamber of the plasma filter device. The control module includes a signal receiving unit, a signal processing unit, and an execution unit. The signal receiving unit is configured to receive the plasma density signal and transmit it to the signal processing unit. The signal processing unit determines and processes the plasma density signal. When the plasma density signal is greater than a preset value, an opening closing instruction is issued to the execution unit; when the plasma density signal is less than a preset value, an opening opening instruction is issued to the execution unit. The execution unit receives and executes the opening closing / opening instruction issued by the signal processing unit. The opening opening can be automatically adjusted according to the preset value, automatically making a trade-off between low substrate damage and high reaction rate to achieve the desired comprehensive effect.

[0008] In one embodiment, the first passage is located outside the second passage, and the plasma filter device body is located above the wafer.

[0009] In one embodiment, when the opening is closed, plasma, after formation, swirls upward within the first passage, diffuses over the top of the baffle, and then flows downward within the second passage. The swirling of plasma within the first passage increases the probability of plasma extinguishing with the sidewalls of the first passage, further removing some of the plasma.

[0010] In one embodiment, the cross-sectional area of ​​the upper portion of the second passage is smaller than the cross-sectional area of ​​the lower portion of the second passage, the plasma filter body is shaped like a truncated cone, and the first passage is shaped like a hollow truncated cone. The smaller cross-sectional area of ​​the upper portion of the second passage can reduce the probability of plasma entering the first passage when the opening is closed.

[0011] In one embodiment, the baffle includes a sloped surface. When the opening is closed, plasma, after formation, diffuses obliquely upward within the first path, passes over the top of the baffle, and then flows downward within the second path. The sloped surface of the baffle increases the probability of plasma extinguishing with the baffle, further removing some of the plasma.

[0012] In one embodiment, the baffle is grounded and includes a conductive baffle, and includes one or a combination of aluminum baffles, aluminum nitride baffles, and aluminum oxide baffles. The grounding of the baffle can extinguish charged ions that come into contact with it and conduct away the generated charge.

[0013] In one embodiment, the second passage is provided with a filter plate, the filter plate having at least one layer, and the filter plate having through holes, the through holes including straight through holes or curved through holes. The filter plate can further filter and remove a portion of the plasma, and the curved through holes can further filter and remove a portion of the plasma.

[0014] In one embodiment, an upper filter plate is provided at the top of the second passage, and a lower filter plate is provided at the bottom of the second passage, so as to further filter and remove part of the plasma.

[0015] In one embodiment, an air inlet is provided at the lower end of the first passage. Gas entering through the air inlet is excited to form plasma within the first passage. The number of the air inlets is symmetrically distributed around the periphery of the second passage. The air inlet is directed horizontally toward the central axis of the second passage, or the angle between the air inlet direction and the direction from the air inlet position to the central axis of the second passage is greater than 0 degrees and less than or equal to 90 degrees. Providing an air inlet at the lower end can further increase the probability of plasma extinguishing with the baffle when the opening is closed. The angle between the air inlet direction and the direction from the air inlet position to the central axis of the second passage is greater than 0 degrees and less than or equal to 90 degrees, which can cause the plasma to swirl within the first passage when the opening is closed, further increasing the probability of plasma extinguishing with the sidewall of the first passage.

[0016] In one embodiment, a coupling coil is disposed on the outer side of the lower end of the first passage. Gas entering through the gas inlet is excited at the coupling coil within the first passage to form plasma. The coupling coil disposed on the outer side of the lower end of the first passage can further increase the probability of plasma extinguishing by collision with the sidewall of the first passage when the opening is closed.

[0017] In one embodiment, the top of the opening is lower than the top of the coupling coil. This allows more plasma to pass through the opening directly into the second path after formation when the opening is opened, thereby increasing plasma density and improving reaction rate.

[0018] The present invention also provides a plasma filtering method, comprising: filtering plasma using the above-mentioned plasma filtering device.

[0019] In the above-mentioned plasma filtering method, when the opening is closed, after the plasma is formed, it first diffuses upward in the first passage, passes over the top of the baffle, and then flows downward in the second passage. When the plasma diffuses upward in the first passage, part of the plasma collides with the sidewall of the first passage and is filtered and removed, thereby reducing the plasma density and reducing damage to the substrate. When the opening is opened, at least part of the plasma formed in the first passage can directly enter the second passage through the opening, thereby increasing the plasma density and improving the reaction rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A cross-sectional view of the plasma filter device of the present invention when the opening is closed;

[0021] Figure 2 A cross-sectional view of the plasma filter device of the present invention when the opening is opened;

[0022] Figure 3 A top view of the baffle in the first embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the opening and closing in the first embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the opening in the first embodiment of the present invention;

[0025] Figure 6 A top view of a baffle in a second embodiment of the present invention;

[0026] Figure 7 This is a schematic diagram of the opening and closing in the second embodiment of the present invention;

[0027] Figure 8This is a schematic diagram of the opening in the second embodiment of the present invention;

[0028] Figure 9a A side view of the baffle when the opening is open in the second embodiment of the present invention;

[0029] Figure 9b A side view of the baffle when the opening is closed in the second embodiment of the present invention;

[0030] Figure 10a The second embodiment of the present invention Figure 8 Enlarged view of part A;

[0031] Figure 10b The second embodiment of the present invention Figure 7 Enlarged view of part A;

[0032] Figure 11a The second embodiment of the present invention Figure 8 Enlarged view of part A;

[0033] Figure 11b The second embodiment of the present invention Figure 7 Enlarged view of part A;

[0034] Figure 12 is a cross-sectional view of a filter plate in the plasma filter device of the present invention;

[0035] In the figure: 10, plasma filter body; 101, baffle; 1011, opening; 1012, upper baffle; 1013, lower baffle; 1014, slide; 1015, first side; 10151, first ridge; 10152, first groove; 1016, second side; 10161, second ridge; 10162, second groove; 1017, joint; 102, filter plate; 1021, upper filter plate; 1022, lower filter plate; 1023, through hole; 20, first passage; 30, second passage; 40, wafer; 50, air inlet; 60, coupling coil; 70, lifting wire; 80, lifting device. DETAILED DESCRIPTION

[0036] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The drawings illustrate preferred embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided solely to provide a more thorough and comprehensive disclosure of the present invention.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0038] In the description of the present invention, it should be understood that the terms "upper", "lower", "vertical", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the methods or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0039] In plasma etching and plasma stripping processes, some process steps have strict requirements on ion damage. Excessively high plasma density will lead to severe ion bombardment on the substrate and excessive charge accumulation on the substrate, causing substrate breakdown damage. However, some process steps require a high reaction rate. The thin film on the substrate surface is stable and hard enough that ion bombardment will not damage the substrate. In this case, increasing the ion density can improve reaction activity and increase the reaction rate.

[0040] One embodiment, such as Figures 1 to 12 As shown, a plasma filter device is provided, comprising: a first passage 20 and a second passage 30 located in a plasma filter device body 10, a baffle 101 is provided between the first passage 20 and the second passage 30, and an opening 1011 with an adjustable opening is provided on the baffle 101, as shown in FIG. Figure 1 As shown, when the opening 1011 is closed, after the plasma is formed, it first diffuses upward in the first passage 20, passes over the top of the baffle 101, and then flows downward in the second passage 30; Figure 2 As shown, when the opening 1011 is opened, at least a portion of the plasma formed in the first passage 20 directly enters the second passage 30 through the opening 1011 .

[0041] In this embodiment, in the plasma filtering device, when the opening 1011 is closed, after the plasma is formed, it first diffuses upward within the first passage 20, passes over the top of the baffle 101, and then flows downward within the second passage 30. When the plasma diffuses upward within the first passage 20, part of the plasma collides with the sidewall of the first passage 20 and is filtered and removed, thereby reducing the plasma density and alleviating damage to the substrate. When the opening 1011 is opened, at least part of the plasma formed in the first passage 20 can directly enter the second passage 30 through the opening 1011, thereby increasing the plasma density and improving the reaction rate.

[0042] In one embodiment, a control module is further included to control the opening of opening 1011. When opening 1011 is closed, the degree of ion damage is reduced and the reaction rate is reduced; when opening 1011 is open, the degree of ion damage is increased and the reaction rate is increased. The opening of opening 1011 can be controlled in real time according to demand, switching between low substrate damage and high reaction rate at any time according to demand.

[0043] The position of the control module is not limited, and the control module can be located inside or outside the reaction chamber.

[0044] In one embodiment, a plasma density detection module is further included to detect a plasma density signal within the reaction chamber of the plasma filter device. The control module receives the plasma density signal and controls the opening of the opening 1011 accordingly. When the plasma density signal is greater than a preset value, the control module controls the opening 1011 to close; when the plasma density signal is less than the preset value, the control module controls the opening 1011 to open. The opening of the opening 1011 can be automatically adjusted according to the preset value, automatically making a trade-off between low substrate damage and high reaction rate to achieve the desired comprehensive effect.

[0045] The control module includes a signal receiving unit, a signal processing unit, and an execution unit. The signal receiving unit is used to receive a plasma density signal and transmit it to the signal processing unit. The signal processing unit judges and processes the plasma density signal. When the plasma density signal is greater than a preset value, an opening 1011 closing instruction is sent to the execution unit; when the plasma density signal is less than the preset value, an opening 1011 opening instruction is sent to the execution unit. The execution unit is used to receive and execute the opening 1011 closing instruction / opening 1011 instruction issued by the signal processing unit.

[0046] In one embodiment, the plasma density detection module includes an ion density analysis system that can characterize the degree of substrate ion damage.

[0047] In one embodiment, the plasma density detection module includes a Langmuir probe.

[0048] In one embodiment, the opening degree of the opening 1011 can also be adjusted manually.

[0049] The first embodiment, as Figures 3 to 5As shown, the baffle 101 includes an upper baffle 1012 and a lower baffle 1013, and the gap between the upper baffle 1012 and the lower baffle 1013 constitutes an opening 1011. The baffle 101 also includes a lifting device 80, and the lifting device 80 is connected to the upper baffle 1012 through a lifting component. The lifting device 80 lifts / lowers the lifting component to adjust the relative position between the upper baffle 1012 and the lower baffle 1013 to adjust the opening 1011. When the upper baffle 1012 and the lower baffle 1013 are closed, the opening 1011 is closed; when the upper baffle 1012 and the lower baffle 1013 are separated, the opening 1011 is opened.

[0050] In one embodiment, the lifting member comprises a lifting wire.

[0051] The pulling member may also be a rigid structure.

[0052] The upper baffle 1012 is connected to the lifting device 80 through the pulling line 70. When the opening 1011 needs to be opened, the lifting device 80 retracts the pulling line 70, and the corresponding upper baffle 1012 will be lifted, the distance between the upper baffle 1012 and the lower baffle 1013 will be increased, and the opening 1011 will be opened; when the opening 1011 needs to be closed, the lifting device 80 relaxes the pulling line 70, the corresponding upper baffle 1012 will be lowered, the distance between the upper baffle 1012 and the lower baffle 1013 will be closed, and the opening 1011 will be closed.

[0053] The opening degree of the opening 1011 can also be adjusted manually by pulling the lower pulling line 70 .

[0054] The second embodiment, as Figures 7-8 、 Figures 9a-9b As shown, a slide 1014 is provided at a position corresponding to the opening 1011 on the baffle 101, and a driving device is also included. The driving device is connected to the slide 1014, and the position of the slide 1014 is adjusted by the driving device to adjust the opening 1011. When the slide 1014 completely covers the opening 1011, the opening 1011 is closed; when the slide 1014 does not completely cover the opening 1011, the opening 1011 is opened.

[0055] In one embodiment, the driving device includes a cylinder, which is connected to the slide 1014 and drives the slide 1014 to move. When the slide 1014 moves to completely cover the opening 1011, the opening 1011 is closed; when the slide 1014 moves to not completely cover the opening 1011, the opening 1011 is opened.

[0056] The position of the slide 1014 can also be manually adjusted to adjust the opening degree of the opening 1011 , for example, the slide 1014 can be pushed up to close the opening 1011 , and the slide 1014 can be pulled down to open the opening 1011 .

[0057] In one embodiment, the opening 1011 can be opened / closed along the horizontal direction or the vertical direction.

[0058] In one embodiment, Figure 6 As shown, the number of openings 1011 is greater than or equal to 3. For example, the number of openings 1011 can be 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18, or 20.

[0059] In the second embodiment, as Figures 10a to 11b As shown, when the opening 1011 is closed, the first side 1015 of the joint 1017 includes at least one first ridge 10151 and at least one first groove 10152. For example, the number of the first ridges 10151 can be 1, 2, 3, 4, 5, 6, 8, or 10, and the number of the first grooves 10152 can be 1, 2, 3, 4, 5, 6, 8, or 10. The second side 1016 joined to the first side 1015 includes a second groove 10162 joined to the first ridge 10151 and a second ridge 10161 joined to the first groove 10152. This prevents plasma from entering the second passage 30 through the joint 1017 of the opening 1011 when the opening 1011 is closed.

[0060] In one embodiment, directions of the first convex strips 10151 , the first concave strips 10152 , the second convex strips 10161 , and the second concave strips 10162 are all perpendicular to the direction in which the opening 1011 enters the plasma.

[0061] In one embodiment, Figures 10a-10b As shown, when the opening 1011 is closed, the first side 1015 of the joint 1017 includes a first concave 10152 located in the middle and first ridges 10151 located on both sides of the first concave 10152. The second side 1016 joined to the first side 1015 includes a second ridge 10161 located in the middle and joined to the first concave 10152, and second concave ridges 10162 located on both sides and joined to the first ridge 10151. This prevents plasma from entering the second passage 30 through the joint 1017 of the opening 1011 when the opening 1011 is closed.

[0062] In one embodiment, Figure 11a-11bAs shown, when the opening 1011 is closed, the first side 1015 of the joint 1017 includes a first ridge 10151 on one side and a first groove 10152 on the other side adjacent to the first ridge 10151. The second side 1016 joined to the first side 1015 includes a second groove 10162 joined to the first ridge 10151 and a second ridge 10161 joined to the first groove 10152. Therefore, when the opening 1011 is closed, plasma cannot enter the second passage 30 through the joint 1017 of the opening 1011.

[0063] In one embodiment, the first passage 20 is located outside the second passage 30 .

[0064] In one embodiment, the plasma filter body 10 is located above the wafer 40 .

[0065] In one embodiment, when the opening 1011 is closed, the plasma, after being formed, first swirls upward within the first passage 20, spreads over the top of the baffle 101, and then flows downward within the second passage 30. The swirl of the plasma within the first passage 20 can increase the probability of the plasma colliding with the sidewall of the first passage 20, thereby further removing part of the plasma.

[0066] In one embodiment, the cross-sectional area of ​​the upper portion of the second passage 30 is smaller than that of the lower portion of the second passage 30. The smaller cross-sectional area of ​​the upper portion of the second passage 30 can reduce the probability of plasma entering the first passage 20 when the opening 1011 is closed.

[0067] In one embodiment, the shape of the plasma filter body 10 includes a truncated cone.

[0068] In one embodiment, the shape of the first passage 20 comprises a hollow frustum.

[0069] In one embodiment, the baffle 101 includes an inclined surface. When the opening 1011 is closed, the plasma, after being formed, first diffuses upward in the first passage 20, passes over the top of the baffle 101, and then flows downward in the second passage 30. The baffle 101 is grounded to extinguish charged ions that come into contact with it and conduct away the generated charge.

[0070] In one embodiment, the baffle 101 is grounded. Grounding the baffle 101 increases the probability of plasma extinguishing with the baffle 101 and conducts away the charge generated by the extinguishing.

[0071] In one embodiment, the baffle 101 includes a conductor baffle 101 , and the baffle 101 includes one or a combination of an aluminum baffle 101 , an aluminum nitride baffle 101 , and an aluminum oxide baffle 101 .

[0072] In one embodiment, the second passage 30 is provided with a filter plate 102, and the number of layers of the filter plate 102 includes at least 1. The filter plate 102 can further filter and remove part of the plasma.

[0073] In one embodiment, the filter plate 102 is provided with a through hole 1023, which includes a straight through hole 1023 or a curved through hole 1023. The curved through hole 1023 can further filter and remove part of the plasma, such as Figure 12 shown.

[0074] In one embodiment, an upper filter plate 1021 is provided at the top of the second passage 30, and a lower filter plate 1022 is provided at the bottom of the second passage 30, so as to further filter and remove part of the plasma.

[0075] In one embodiment, the lower end of the first passage 20 is provided with an air inlet 50, and the gas entering through the air inlet 50 is excited to form plasma in the first passage 20. The lower end is provided with an air inlet 50 to further increase the probability of plasma extinguishing by colliding with the baffle 101 when the opening 1011 is closed.

[0076] In one embodiment, the number of the air inlets 50 includes a plurality.

[0077] In one embodiment, the plurality of air inlets 50 are centrally symmetrically distributed around the periphery of the second passage 30 .

[0078] In one embodiment, the air inlet 50 is directed horizontally toward the central axis of the second passage 30 .

[0079] In one embodiment, the angle between the direction of the air inlet 50 and the direction horizontally pointing from the position of the air inlet 50 to the central axis of the second passage 30 is greater than 0 degrees and less than or equal to 90 degrees. For example, the angle between the direction of the air inlet 50 and the direction horizontally pointing from the position of the air inlet 50 to the central axis of the second passage 30 can be 10 degrees, 20 degrees, 30 degrees, 45 degrees, 60 degrees, or 90 degrees. The angle between the direction of the air inlet 50 and the direction horizontally pointing from the position of the air inlet 50 to the central axis of the second passage 30 is greater than 0 degrees and less than or equal to 90 degrees. This can cause the plasma to swirl within the first passage 20 when the opening 1011 is closed, further increasing the probability of the plasma colliding with the sidewall of the first passage 20.

[0080] In one embodiment, a coupling coil 60 is disposed on the outer side of the lower end of the first passage 20. Gas entering through the gas inlet 50 is excited at the coupling coil 60 within the first passage 20 to form plasma. Providing the coupling coil 60 on the outer side of the lower end of the first passage 20 can further increase the probability of plasma extinguishing by collision with the sidewall of the first passage 20 when the opening 1011 is closed.

[0081] In one embodiment, the top of the opening 1011 is lower than the top of the coupling coil 60. The top of the opening 1011 is lower than the top of the coupling coil 60, so that when the opening 1011 is opened, more plasma can directly enter the second passage 30 through the opening 1011 after being formed, thereby increasing the plasma density and improving the reaction rate.

[0082] In one embodiment, the sidewalls of the first via 20 are grounded. Grounding the sidewalls increases the probability of plasma extinguishing with the sidewalls and conducts away the charges generated by the extinguishing.

[0083] In one embodiment, the generatrix of the baffle 101 includes a straight line, a curve, or a combination thereof. The curve can further increase the probability of extinguishing the plasma and the baffle 101.

[0084] In one embodiment, the filter plate 102 may also be a curved surface, and the cross section of the filter plate 102 may be an arc, a curve, etc.

[0085] In one embodiment, the number of layers of the filter plate 102 includes at least one layer, for example, the number of layers of the filter plate 102 can be 1 layer, 2 layers, 3 layers, 4 layers, 5 layers, or 6 layers, so as to further filter and remove part of the plasma.

[0086] In one embodiment, the filter plate 102 is provided with through holes 1023. The shapes of the through holes 1023 include circular, rectangular, and polygonal, or a combination thereof. The through holes 1023 may be evenly distributed or unevenly distributed, for example, with a greater distribution density in the center of the filter plate 102 than at the edges, or a lesser distribution density in the center of the filter plate 102 than at the edges.

[0087] In one embodiment, the diameter of the through hole 1023 is between 0.1 mm and 10 mm. For example, the diameter of the through hole 1023 can be 0.1 mm, 1 mm, 2 mm, 4 mm, 5 mm, 8 mm, or 10 mm.

[0088] In one embodiment, the width of the opening 1011 is between 1 mm and 100 mm. For example, the width of the opening 1011 can be 1 mm, 10 mm, 20 mm, 30 mm, 50 mm, 70 mm, 80 mm, or 100 mm.

[0089] In one embodiment, the number of the air inlets 50 is at least four. For example, the number of the air inlets 50 may be four, five, six, seven, eight, ten, or twelve.

[0090] One embodiment provides a plasma filtering method, comprising: filtering plasma using the above-mentioned plasma filtering device.

[0091] In this embodiment, in the above-mentioned plasma filtering method, when the opening 1011 is closed, after the plasma is formed, it first diffuses upward in the first passage 20, passes over the top of the baffle 101, and then flows downward in the second passage 30. When the plasma diffuses upward in the first passage 20, part of the plasma collides with the side wall of the first passage 20 and is filtered and removed, thereby reducing the plasma density and reducing damage to the substrate. When the opening 1011 is opened, at least part of the plasma formed in the first passage 20 can directly enter the second passage 30 through the opening 1011, which can increase the plasma density and improve the reaction rate.

[0092] In one embodiment, when low substrate damage and low reaction rate are required, the opening 1011 is closed; when a high reaction rate is required, the opening 1011 is opened; when moderate substrate damage and reaction rate are required, the opening 1011 is partially opened.

[0093] The plasma filtering device and filtering method can be applied to processes such as plasma etching and plasma stripping.

[0094] Plasma etching: In a typical plasma etching process, different process gas combinations (such as CxFy, O2, Ar, etc.) are excited by radio frequency (RF) to form a plasma. Under the influence of the electric field between the upper and lower electrodes of the etching chamber, the formed plasma physically bombards and chemically reacts with the surface of the wafer 40, completing the etching process of the designed pattern on the wafer 40. Typical etching chambers include capacitively coupled chambers (CCP) and inductively coupled chambers (ICP).

[0095] Plasma stripping: A plasma stripper utilizes plasma technology to remove surface material. Stripping is a surface treatment technique used to remove residual photoresist from the wafer 40, providing a clean surface for subsequent processing. The plasma stripper operates by generating plasma through electrical discharge and introducing it into the stripping area. Organic matter on the surface reacts with the activated plasma, oxidizing and decomposing it into gas, thereby removing the photoresist from the wafer 40.

[0096] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0097] The above embodiments merely illustrate several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A plasma filtering device, characterized in that: include: a first passage and a second passage located within a plasma filter body; a baffle disposed between the first and second passages; and an opening on the baffle having an adjustable opening; when the opening is closed, plasma, after being formed, diffuses upward within the first passage, passes over a top of the baffle, and then flows downward within the second passage, thereby reducing ion damage and a reaction rate; when the opening is open, at least a portion of the plasma, after being formed within the first passage, directly enters the second passage through the opening, thereby increasing ion damage and a reaction rate; the baffle includes an upper baffle and a lower baffle, the opening being formed by a gap between the upper and lower baffles; and a lifting device connected to the upper baffle via a lifting member, wherein the lifting device lifts / lowers the lifting member to adjust the relative position between the upper and lower baffles to adjust the opening; and when the upper and lower baffles are closed, the opening is closed; When the upper baffle and the lower baffle are separated, the opening is opened.

2. A plasma filtering device according to claim 1, characterized in that: The device further includes a control module for controlling the opening of the opening, and a plasma density detection module for detecting a plasma density signal in a reaction chamber of the plasma filtering device. The control module includes a signal receiving unit, a signal processing unit, and an execution unit. The signal receiving unit is used to receive the plasma density signal and transmit it to the signal processing unit. The signal processing unit judges and processes the plasma density signal. When the plasma density signal is greater than a preset value, the execution unit issues an opening closing instruction; when the plasma density signal is less than the preset value, the execution unit issues an opening opening instruction. The execution unit receives and executes the opening closing instruction / opening instruction issued by the signal processing unit.

3. The plasma filtering device according to claim 1, characterized in that: The first passage is located outside the second passage, the plasma filter device body is located above the wafer, the cross-sectional area of ​​the upper portion of the second passage is smaller than the cross-sectional area of ​​the lower portion of the second passage, the shape of the plasma filter device body includes a truncated cone, the shape of the first passage includes a hollow truncated cone, the baffle is grounded, the baffle includes a conductor baffle, the baffle includes one or a combination of aluminum baffles, aluminum nitride baffles, and aluminum oxide baffles, the second passage is provided with a filter plate, the number of layers of the filter plate includes at least one layer, the filter plate is provided with a through hole, the through hole includes a straight through hole or a curved through hole, an upper filter plate is provided at the top of the second passage, and a lower filter plate is provided at the bottom of the second passage.

4. The plasma filtering device according to claim 1, characterized in that: When the opening is closed, after being formed, plasma first swirls and diffuses upward in the first passage, passes over the top of the baffle, and then flows downward in the second passage.

5. The plasma filtering device according to claim 1, characterized in that: The baffle includes an inclined surface. When the opening is closed, after being formed, the plasma first diffuses obliquely upward in the first passage, passes over the top of the baffle, and then flows downward in the second passage.

6. The plasma filtering device according to claim 1, characterized in that: An air inlet is provided at the lower end of the first passage, and the gas entering from the air inlet is excited to form plasma in the first passage. The number of the air inlets includes several, and the several air inlets are centrally symmetrically distributed on the periphery of the second passage. A coupling coil is provided on the outer side of the lower end of the first passage, and the gas entering from the air inlet is excited to form plasma at the coupling coil in the first passage, and the top of the opening is lower than the top of the coupling coil.

7. A plasma filtration method, characterized in that: Plasma is filtered using the plasma filtering device according to any one of claims 1 to 6.

Images