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 an upwardly directed first plasma path and a downwardly directed second plasma path located within the plasma filtering device body and connected to the first plasma path. The first plasma path includes sidewalls. After plasma is formed, it diffuses upward within the first plasma path before flowing downward within the second plasma path. In the plasma filtering device, when plasma diffuses upward within the first plasma path, a portion of the plasma collides with the sidewalls of the first plasma path and is filtered and removed, thereby reducing plasma density and mitigating damage to the substrate.

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 and plasma stripping. Existing equipment using these processes will cause certain damage to the substrate. 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 filtering device, comprising: an upward first plasma path and a downward second plasma path located within a main body of the plasma filtering device and connected to the first plasma path. The first plasma path comprises a side wall, the top of the side wall being higher than the bottom of the side wall. The outer side of the first plasma path comprises a plasma excitation module, the top of the first plasma path being higher than the plasma excitation module. After plasma is excited by the plasma excitation module inside the first plasma path and formed, it first flows upward along the first plasma path and then flows downward within the second plasma path.

[0005] In the plasma filtering device, when plasma diffuses upward in the first plasma channel, part of the plasma collides with the side wall of the first plasma channel and is filtered and removed, thereby reducing the plasma density and alleviating damage to the substrate.

[0006] In one embodiment, the first plasma channel is located outside the second plasma channel.

[0007] In one embodiment, after the plasma is formed, it first swirls and diffuses upward in the first plasma path and then flows downward in the second plasma path. The swirl of the plasma in the first plasma path can increase the probability of the plasma extinguishing with the sidewall, thereby further removing part of the plasma.

[0008] In one embodiment, the plasma filter device body is located above the wafer.

[0009] In one embodiment, the cross-sectional area of ​​the upper portion of the second plasma path is smaller than the cross-sectional area of ​​the lower portion of the second plasma path. The smaller cross-sectional area of ​​the upper portion of the second plasma path can reduce the probability of plasma entering the first plasma path.

[0010] In one embodiment, the shape of the plasma filter body includes a truncated cone.

[0011] In one embodiment, the sidewall of the first plasma path includes a sloped surface. After plasma is formed, it diffuses obliquely upward within the first plasma path and then flows downward within the second plasma path. The sloped surface of the sidewall of the first plasma path increases the probability of plasma extinguishing with the sidewall, thereby further removing some of the plasma.

[0012] In one embodiment, the shape of the first plasma channel includes a hollow truncated cone.

[0013] In one embodiment, the sidewall of the first plasma passage is grounded, which increases the probability of plasma extinguishing with the sidewall and conducts away the charge generated by the extinguishing.

[0014] In one embodiment, the sidewall of the first plasma passage includes an inner sidewall and an outer sidewall located outside the inner sidewall. The plasma filter body includes a body sidewall, the inner sidewall is formed by the body sidewall, and the outer sidewall is formed by the chamber wall. The inner sidewall is formed by the body sidewall, and the outer sidewall is formed by the chamber wall. This ingenious design can reduce the production cost of the device.

[0015] In one embodiment, the sidewall of the body is grounded, which increases the probability of plasma extinguishing with the sidewall and conducts away the charge generated by the extinguishing.

[0016] In one embodiment, the sidewalls include conductive sidewalls, and the sidewalls include one or a combination of aluminum sidewalls, aluminum nitride sidewalls, and aluminum oxide sidewalls, so as to conduct away the charges generated by the collision.

[0017] In one embodiment, the generatrix of the side wall includes a straight line, a curve, or a combination thereof. The curve can further increase the probability of plasma extinguishing with the side wall.

[0018] In one embodiment, the second plasma passage is provided with a filter plate, which can further filter and remove part of the plasma.

[0019] In one embodiment, the filter plate comprises at least one layer, which can further filter and remove part of the plasma.

[0020] In one embodiment, the filter plate is provided with through holes.

[0021] In one embodiment, the through hole includes a straight through hole or a curved through hole. The curved through hole can further filter and remove part of the plasma.

[0022] In one embodiment, an upper filter plate is provided on the top of the second plasma path, and a lower filter plate is provided on the bottom of the second plasma path, so as to further filter and remove part of the plasma.

[0023] In one embodiment, a gas inlet is provided at the lower end of the first plasma passage, and gas entering through the gas inlet is excited to form plasma in the first plasma passage. The gas inlet at the lower end can further increase the probability of plasma extinguishing by colliding with the sidewall.

[0024] In one embodiment, the plasma excitation module includes a coupling coil disposed on the outer side of the lower end of the first plasma path. Gas entering through the gas inlet is excited at the coupling coil within the first plasma path to form plasma. The coupling coil disposed on the outer side of the lower end of the first plasma path can further increase the probability of plasma extinguishing by colliding with the sidewall.

[0025] In one embodiment, the number of the gas inlets includes a plurality, and the plurality of gas inlets are centrally symmetrically distributed around the periphery of the second plasma channel.

[0026] In one embodiment, the gas inlet is horizontally directed toward the central axis of the second plasma channel, which can further increase the probability of plasma extinguishing by colliding with the side wall.

[0027] In one embodiment, the angle between the direction of the gas inlet and the direction horizontally pointing from the gas inlet to the central axis of the second plasma channel is greater than 0 degrees and less than or equal to 90 degrees. This can cause the plasma to swirl within the first plasma channel, further increasing the probability of plasma extinguishing with the sidewall.

[0028] The present invention also provides a plasma filtering method, comprising: using the above-mentioned plasma filtering device to filter plasma.

[0029] In the above plasma filtering method, when plasma diffuses upward in the first plasma channel, part of the plasma collides with the sidewall of the first plasma channel and is filtered and removed, thereby reducing the plasma density and alleviating damage to the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a cross-sectional view of the plasma filter device of the present invention in the case where the generatrix of the side wall is a straight line.

[0031] Figure 2 This is a cross-sectional view of a plasma filter device according to the present invention in which the generatrix of the side wall is a curve.

[0032] Figure 3 It is a cross-sectional view of the filter plate in the plasma filter device of the present invention.

[0033] In the figure: 10, plasma filter device body; 101, body side wall; 102, filter plate; 1021, upper filter plate; 1022, lower filter plate; 1023, through hole; 20, first plasma path; 201, side wall; 2011, inner wall; 2012, outer wall; 30, second plasma path; 40, chamber wall; 50, air inlet; 60, coupling coil; 70, wafer. DETAILED DESCRIPTION

[0034] 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.

[0035] 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.

[0036] 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.

[0037] In existing plasma etching and plasma stripping processes, the plasma density is too high, resulting in a too fast etching rate, severe ion bombardment on the substrate, and excessive charge accumulation on the substrate, causing substrate breakdown damage.

[0038] One embodiment, such as Figures 1 to 3As shown, a plasma filtering device is provided, comprising: an upward first plasma passage 20 and a downward second plasma passage 30 located in a plasma filtering device body 10 and connected to the first plasma passage 20, wherein the first plasma passage 20 and the second plasma passage 30 located in the plasma filtering device body 10, the first plasma passage 20 comprises a side wall 201, the top of the side wall 201 is higher than the bottom of the side wall 201, the outer side of the first plasma passage 20 comprises a plasma excitation module, the top of the first plasma passage 20 is higher than the plasma excitation module, and plasma is excited by the plasma excitation module inside the first plasma passage 20 and then flows upward along the first plasma passage 20 and then downward in the second plasma passage 30.

[0039] In this embodiment, when the plasma diffuses upward in the first plasma channel 20, part of the plasma collides with the sidewall 201 of the first plasma channel 20 and is filtered out, thereby reducing the plasma density and alleviating damage to the substrate.

[0040] In one embodiment, the plasma excitation module is located outside the lower end of the first plasma passage 20 .

[0041] In one embodiment, the length of the first plasma channel 20 is between 1 cm and 100 cm. For example, the length of the first plasma channel 20 can be 1 cm, 10 cm, 20 cm, 40 cm, 50 cm, 70 cm, 90 cm, or 100 cm.

[0042] In one embodiment, the length of the first plasma channel 20 is at least 1 / 5 of the length of the second plasma channel 30. For example, the length of the first plasma channel 20 may be 1 / 5, 1 / 4, 1 / 3, or 1 / 2 of the length of the second plasma channel 30. The length of the first plasma channel 20 may also be equal to or greater than the length of the second plasma channel 30.

[0043] In one embodiment, the first plasma channel 20 surrounds at least a portion of the second plasma channel 30 . For example, the first plasma channel 20 may surround an upper portion of the second plasma channel 30 , or may surround the entire outer sidewall of the second plasma channel 30 .

[0044] In one embodiment, the first plasma passage 20 nests the second plasma passage 30 .

[0045] In one embodiment, the first plasma passage 20 is located outside the second plasma passage 30 .

[0046] In one embodiment, after being formed, plasma first swirls and diffuses upward in the first plasma channel 20 and then flows downward in the second plasma channel 30. The swirl of plasma in the first plasma channel 20 can increase the probability of plasma extinguishing with the sidewall 201, and can further remove part of the plasma.

[0047] In one embodiment, the plasma filter device body 10 is located above the wafer 70 .

[0048] In one embodiment, the cross-sectional area of ​​the upper portion of the second plasma channel 30 is smaller than the cross-sectional area of ​​the lower portion of the second plasma channel 30. The smaller cross-sectional area of ​​the upper portion of the second plasma channel 30 can reduce the probability of plasma entering the first plasma channel 20.

[0049] In one embodiment, the shape of the plasma filter body 10 includes a truncated cone.

[0050] In one embodiment, the sidewall 201 of the first plasma channel 20 includes a sloped surface. After plasma is formed, it diffuses obliquely upward within the first plasma channel 20 and then flows downward within the second plasma channel 30. The sloped surface of the sidewall 201 of the first plasma channel 20 can increase the probability of extinguishing the plasma with the sidewall 201, thereby further removing part of the plasma.

[0051] In one embodiment, the shape of the first plasma passage 20 comprises a hollow truncated cone.

[0052] In one embodiment, the sidewall 201 of the first plasma passage 20 is grounded. Grounding the sidewall 201 increases the probability of plasma extinguishing with the sidewall 201 and conducts away the charge generated by the extinguishing.

[0053] In one embodiment, the sidewall 201 of the first plasma passage 20 includes an inner sidewall 2011 and an outer sidewall 2012 located outside the inner sidewall 2011. The plasma filter device body includes a body sidewall 101. The inner sidewall 2011 is formed by the body sidewall 101, and the outer sidewall 2012 is formed by the chamber wall 40. The inner sidewall 2011 is formed by the body sidewall 101, and the outer sidewall 2012 is formed by the chamber wall 40. This clever design can reduce the production cost of the device.

[0054] In one embodiment, the inner sidewall 2011 includes an upwardly inclined slope.

[0055] In one embodiment, the body sidewall 101 is grounded. Grounding the body sidewall 101 increases the probability of plasma extinguishing with the sidewall 201 and conducts away the charge generated by the extinguishing.

[0056] In one embodiment, the sidewall 201 includes a conductor sidewall 201, and the sidewall 201 includes one or a combination of aluminum sidewall 201, aluminum nitride sidewall 201, and aluminum oxide sidewall 201, so as to conduct the charge generated by the collision.

[0057] In one embodiment, the busbar of the side wall 201 includes one or more combinations of straight lines and curves. The curve can further increase the probability of plasma extinguishing with the side wall 201. Figure 1 As shown, when the busbar is a curve, Figure 2 shown.

[0058] In one embodiment, the second plasma passage 30 is provided with a filter plate 102. The filter plate 102 can further filter and remove part of the plasma.

[0059] 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.

[0060] 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.

[0061] In one embodiment, the filter plate 102 is provided with through holes 1023. In one embodiment, the shape of the through holes 1023 includes one or a combination of circular, rectangular, and polygonal. The through holes 1023 can 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 than at the edges.

[0062] 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.

[0063] In one embodiment, the through hole 1023 includes a straight through hole 1023 or a curved through hole 1023, wherein the curved through hole 1023 is as follows: Figure 3 The curved through hole 1023 can further filter and remove part of the plasma.

[0064] In one embodiment, an upper filter plate 1021 is provided at the top of the second plasma channel 30, and a lower filter plate 1022 is provided at the bottom of the second plasma channel 30, so as to further filter and remove part of the plasma.

[0065] In one embodiment, a gas inlet 50 is provided at the lower end of the first plasma channel 20. Gas entering through the gas inlet 50 is excited to form plasma in the first plasma channel 20. The gas inlet 50 at the lower end can further increase the probability of plasma extinguishing by colliding with the sidewall 201.

[0066] In one embodiment, the diameter of the air inlet 50 is between 0.1 cm and 10 cm.

[0067] In one embodiment, the top end of the first plasma passage 20 is higher than the gas inlet 50 .

[0068] In one embodiment, the plasma excitation module includes a coupling coil 60 disposed on the outer side of the lower end of the first plasma channel 20. Gas entering through the gas inlet 50 is excited at the coupling coil 60 within the first plasma channel 20 to form plasma. The presence of the coupling coil 60 on the outer side of the lower end of the first plasma channel 20 can further increase the probability of plasma extinguishing by colliding with the sidewall 201.

[0069] In one embodiment, the number of the gas inlets 50 includes a plurality of gas inlets 50 , and the plurality of gas inlets 50 are centrally symmetrically distributed around the periphery of the second plasma channel 30 .

[0070] 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.

[0071] In one embodiment, the gas inlet 50 is horizontally directed toward the central axis of the second plasma channel 30 , which can further increase the probability of plasma extinguishing by colliding with the sidewall 201 .

[0072] In one embodiment, the angle between the direction of the gas inlet 50 and the direction horizontally pointing from the gas inlet 50 to the central axis of the second plasma channel 30 is greater than 0 degrees and less than or equal to 90 degrees. For example, the angle between the direction of the gas inlet 50 and the direction horizontally pointing from the gas inlet 50 to the central axis of the second plasma channel 30 can be 10 degrees, 20 degrees, 30 degrees, 45 degrees, 60 degrees, or 90 degrees. This can cause the plasma to swirl within the first plasma channel 20, further increasing the probability of the plasma colliding with the sidewall 201.

[0073] One embodiment provides a plasma filtering method, comprising: filtering plasma using the above-mentioned plasma filtering device.

[0074] In this embodiment, in the above-mentioned plasma filtering method, when the plasma diffuses upward in the first plasma channel 20, part of the plasma collides with the sidewall 201 of the first plasma channel 20 and is filtered and removed, thereby reducing the plasma density and alleviating damage to the substrate.

[0075] The plasma filtering device and filtering method can be applied to processes such as plasma etching and plasma stripping.

[0076] Plasma etching: In a typical plasma etching process, different process gas combinations (such as CxFy, O2, and Ar) are excited by radio frequency (RF) to form a plasma. Under the influence of the electric field from the upper and lower electrodes in the etching chamber, the formed plasma physically bombards and chemically reacts with the wafer surface, etching the designed pattern on the wafer surface. Typical etching chambers include capacitively coupled chambers (CCP) and inductively coupled chambers (ICP).

[0077] 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 surface, providing a clean wafer 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 surface.

[0078] The technical features of the above embodiments can be combined arbitrarily. 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.

[0079] 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 upward plasma passage and a second downward plasma passage located within a plasma filter body and connected to the first plasma passage, wherein the first plasma passage includes a sidewall, a top of the sidewall is higher than a bottom of the sidewall, the outer side of the first plasma passage includes a plasma excitation module, a top of the first plasma passage is higher than the plasma excitation module, and plasma is excited by the plasma excitation module within the first plasma passage and then flows upward along the first plasma passage and then downward in the second plasma passage; An air inlet is provided at the lower end of the first plasma path, and the gas entering from the air inlet is excited to form plasma in the first plasma path. The number of the air inlets includes several, and the several air inlets are centrally symmetrically distributed on the periphery of the second plasma path. The direction of the air inlet points horizontally to the central axis of the second plasma path, or the angle between the direction of the air inlet and the direction pointing horizontally from the position of the air inlet to the central axis of the second plasma path is greater than 0 degree and less than or equal to 90 degrees.

2. The plasma filtering device according to claim 1, characterized in that: The first plasma passage is located outside the second plasma passage, and the plasma filter device body is located above the wafer.

3. The plasma filtering device according to claim 1, characterized in that: After being formed, plasma first swirls and diffuses upward in the first plasma channel and then flows downward in the second plasma channel.

4. The plasma filtering device according to claim 1, characterized in that: The cross-sectional area of ​​the upper portion of the second plasma path is smaller than the cross-sectional area of ​​the lower portion of the second plasma path. The shape of the plasma filter body includes a truncated cone, and the shape of the first plasma path includes a hollow truncated cone.

5. The plasma filtering device according to claim 1, characterized in that: The sidewall of the first plasma channel includes an inclined surface. After being formed, plasma first diffuses obliquely upward in the first plasma channel and then flows downward in the second plasma channel.

6. The plasma filtering device according to claim 1, characterized in that: The side wall of the first plasma passage includes an inner wall and an outer wall located outside the inner wall. The plasma filtering device body includes a body side wall. The inner wall is formed by the body side wall, and the outer wall is formed by the chamber wall.

7. The plasma filtering device according to claim 6, characterized in that: The side wall of the first plasma passage is grounded, and the side wall of the body is grounded.

8. The plasma filtering device according to claim 1, characterized in that: The sidewalls include conductor sidewalls, and the sidewalls include one or a combination of aluminum sidewalls, aluminum nitride sidewalls, and aluminum oxide sidewalls. The busbars of the sidewalls include one or a combination of straight lines and curves.

9. The plasma filtering device according to claim 1, characterized in that: The second plasma passage is provided with a filter plate, the filter plate has at least one layer, and the filter plate is provided with through holes, which include straight through holes or curved through holes.

10. The plasma filtering device according to claim 1, characterized in that: An upper filter plate is provided at the top of the second plasma passage, and a lower filter plate is provided at the bottom of the second plasma passage.

11. The plasma filtering device according to claim 1, characterized in that: The plasma excitation module includes a coupling coil. The coupling coil is provided outside the lower end of the first plasma path. The gas entering from the gas inlet is excited at the coupling coil in the first plasma path to form plasma.

12. A plasma filtering method, characterized in that: Plasma is filtered using the plasma filtering device described in any one of claims 1 to 11.

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