A remote plasma cleaning kit and method for PECVD chambers

Abstract

This invention provides a remote plasma cleaning kit and method for a PECVD chamber. The kit includes a chamber body, a remote plasma source, a spray head, a liner assembly, and a movable heater. The chamber body comprises an outer chamber and an inner chamber nested within it. The remote plasma source is connected to the chamber body. The spray head is positioned in the upper space between the outer and inner chambers. The liner assembly includes a top liner and a bottom liner stacked along a direction away from the spray head, each liner having uniformly distributed evacuation holes arranged in a row. The liner assembly and the inner chamber together define an evacuation channel. The movable heater is embedded in the liner assembly and moves vertically along it. This invention improves the uniformity and stability of the PECVD chamber cleaning process, significantly increases cleaning efficiency, and reduces particulate contamination in the chamber.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor deposition equipment cleaning technology, specifically relating to a remote plasma cleaning PECVD cavity kit and cleaning method. Background Technology

[0002] Plasma-enhanced chemical vapor deposition (PECVD) is a crucial step in semiconductor manufacturing, used to deposit thin films on substrate surfaces. As the process cycle continues, reaction byproducts and film residues inevitably accumulate on the inner walls and internal components of the PECVD chamber. In particular, due to gas diffusion and cooling effects, some active groups undergo homogeneous reactions before reaching the substrate, generating solid particles that deposit on the chamber walls and top, forming a "film residue layer." These residues not only cause particulate contamination but also affect process stability and yield. Therefore, regular cleaning of the chamber is essential.

[0003] For example, prior art US6835278B2 discloses a remote plasma cleaning system including a high-conductivity delivery line for conveying activated material from a remote plasma generator to a processing chamber. The delivery line preferably has a conductivity greater than 40 liters per second, allowing the power of the remote plasma generator to be maintained at less than about 3 kW. In one embodiment, the activated material is introduced into the processing chamber through one or more inlets located in the side of the processing chamber. In another embodiment, a coaxial injection / emission assembly allows the activated material to be introduced into the processing chamber through an inner tube and gas to be discharged from the processing chamber through an outer tube. Other embodiments incorporate a composite valve and an optical baffle in the delivery system, wherein the composite valve is used to selectively isolate the RPC chamber from the processing chamber, and the optical baffle is used to protect sensitive components of the isolation valve from exposure to ion bombardment and plasma radiation. The processing chamber may also include flow channels, such as lift-pin assemblies, that allow the activated material to clean cavities and components located below a base. End-point detection of remote plasma cleaning can be performed by igniting a second low-power plasma from the activated material generated by the remote plasma generator in the processing chamber and monitoring the emission line (or ratio) from the second plasma using an optical detector. Although this technical solution achieves remote plasma cleaning of the cavity, it still has the following drawbacks: 1) Poor cleaning uniformity, which is not conducive to process stability: The side airflow and air extraction methods result in uneven distribution of cleaning gas in the cavity, which leads to low cleaning uniformity and is not conducive to the stability of the cavity environment, thus affecting process stability; 2) Low cleaning efficiency: The cleaning space is large, the efficiency of indiscriminate cleaning is low, the time consumption is long, and the equipment's capacity per unit time (WPH) is reduced.

[0004] Therefore, how to improve the uniformity and stability of the PECVD chamber cleaning process, while increasing cleaning efficiency, reducing chamber particulate contamination, and extending the chamber maintenance cycle, is an urgent technical challenge to be solved. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a remote plasma cleaning kit and method for PECVD chambers. This invention constructs a synergistic combination of evacuation holes by setting uniformly distributed rows of evacuation holes in the top and bottom linings, and coordinating this with the positioning of a movable heater, achieving a more efficient chamber cleaning effect. This design not only overcomes the uneven airflow problem caused by traditional side-entry or single-point evacuation, improving the uniformity and stability of the PECVD chamber cleaning process, but also, through the adjustment of the movable heater's position, can enhance the cleaning effect of different areas of the chamber in stages, greatly improving cleaning efficiency and reducing chamber particulate contamination. This effectively extends the chamber's maintenance cycle while increasing equipment productivity.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a remote plasma cleaning PECVD chamber kit, the remote plasma cleaning PECVD chamber kit comprising:

[0008] The cavity body includes an outer cavity and an inner cavity nested within the outer cavity.

[0009] A remote plasma source, connected to the cavity body, is used to activate the introduced clean gas and deliver it into the cavity body.

[0010] A spray head is disposed in the upper space between the outer cavity and the inner cavity, and is used to distribute the activated cleaning gas into the interior of the inner cavity.

[0011] The liner assembly includes a top liner and a bottom liner stacked along a direction away from the spray head; the top liner and the bottom liner are respectively provided with a uniformly distributed row of air extraction holes for outputting clean gas; the liner assembly and the inner cavity together define an air extraction channel for discharging the cleaned gas to the outside of the cavity body.

[0012] A movable heater, embedded in the liner assembly, is used to move along the vertical direction of the liner assembly to adapt to the cleaning needs of different positions of the cavity body.

[0013] This invention achieves a more efficient chamber cleaning effect by constructing a coordinated air extraction hole combination structure with uniformly distributed rows of air extraction holes in the top and bottom linings, and coordinating with the position of the movable heater. This design not only overcomes the problem of uneven airflow caused by traditional side air intake or single-point air extraction, which is beneficial to improving the uniformity and stability of the PECVD chamber cleaning process, but also enhances the cleaning effect of each area of ​​the chamber in stages by adjusting the position of the movable heater, which greatly improves the cleaning efficiency and reduces chamber particulate contamination. Thus, it effectively extends the maintenance cycle of the chamber while increasing equipment capacity.

[0014] In this invention, the purpose of activating the introduced cleaning gas is to generate highly active free radicals and ionic substances through a remote plasma source. This allows the originally chemically stable cleaning gas to react rapidly with the thin film residues (such as silicon oxides, silicon nitrides, amorphous silicon, etc.) deposited on the inner wall of the PECVD cavity and the surface of the components at a lower temperature, generating volatile products. This achieves efficient and gentle cleaning of the cavity, avoiding thermal damage to the cavity components caused by high-temperature thermal cleaning.

[0015] In this invention, the uniformly distributed row of exhaust holes in the top liner is designed to work with the movable heater to allow activated cleaning gas to flow through the vicinity of the spray head and the upper space of the inner cavity, thereby specifically removing deposits that easily accumulate in this area. At the same time, the positions of the exhaust holes and the movable heater ensure a stable airflow field in the upper part of the chamber, avoiding eddies and dead zones, and improving the efficiency and uniformity of cleaning the upper part of the chamber. The uniformly distributed row of exhaust holes in the bottom liner is designed to work in conjunction with the exhaust hole structure in the top liner when the movable heater moves down to the area where the bottom liner is located, to guide the activated cleaning gas to flow fully through the lower space of the inner cavity, thereby enhancing the removal of stubborn residues at the bottom.

[0016] It should be noted that the present invention does not specifically limit the materials of the top and bottom linings. For example, they may be ceramic materials and anti-corrosion coatings.

[0017] In this invention, the movable heater serves to support the wafer and control its temperature. During the cleaning process, the height of the heater can be adjusted to divide the chamber into different spaces to achieve different cleaning effects in different areas.

[0018] Preferably, the air extraction hole structure includes at least one row of air extraction holes, such as a single row of air extraction holes, a double row of air extraction holes, or a triple row of air extraction holes.

[0019] Preferably, the remote plasma cleaning PECVD chamber kit further includes a vacuum pump, which is connected to the evacuation channel via a pipeline. It should be noted that the vacuum pump and the evacuation channel are connected via a pipeline, thereby allowing the cleaning gas and cleaning products in the chamber and evacuation channel to be drawn out of the chamber during the cleaning process.

[0020] Preferably, the spray head has a porous structure. For example, the average pore diameter can be 1.4 mm, and the average pore spacing can be 3.2 mm.

[0021] In this invention, the porous spray head can fully control the gas flow rate and direction, so that the activated cleaning gas is delivered to the target area with a uniform concentration field and velocity field, avoiding local airflow impact or cleaning blind spots, which helps to improve the uniformity of cavity cleaning, and improve cleaning efficiency and process stability.

[0022] Preferably, the air extraction channel opening is located on the side wall or bottom of the inner cavity.

[0023] Preferably, the vent structure in the top liner is distributed in the middle region of the top liner. It should be noted that the vent structure is positioned on the top liner so that it is not obstructed by the movable heater.

[0024] In this invention, the air extraction hole structure is distributed in the middle area of ​​the top liner. If the position is changed, the airflow will be deflected, affecting the uniformity of cleaning.

[0025] Preferably, the height of the top liner is 10-15mm, for example, it can be 10mm, 11mm, 12mm, 13mm, 14mm or 15mm, etc.

[0026] Preferably, the average diameter of the air extraction holes in the top liner is 6-6.5 mm, for example, it can be 6 mm, 6.1 mm, 6.2 mm, 6.3 mm, 6.4 mm or 6.5 mm, etc.

[0027] Preferably, the top liner has a cylindrical structure, wherein the distribution density of the air extraction holes along the circumferential direction of the top liner is 7° / hole to 8° / hole, for example, it can be 7° / hole, 7.5° / hole or 8° / hole, etc.

[0028] This invention coordinates the average pore size and distribution density of the air extraction holes in the top liner, which helps to build a uniform and stable airflow field in the upper space of the inner cavity, ensuring the cleaning effect and consistency of the upper space of the inner cavity. If the above requirements are not met, the uniformity of cleaning will be affected.

[0029] Preferably, the vent structure in the bottom liner is distributed in the middle region of the bottom liner. It should be noted that the vent structure is positioned on the bottom liner in a way that it is not obstructed by the movable heater.

[0030] In this invention, the air extraction hole structure is distributed in the middle area of ​​the bottom liner. If the position is changed, the airflow will be deflected, affecting the uniformity of cleaning.

[0031] Preferably, the height of the bottom liner is 10-15mm, for example, it can be 10mm, 11mm, 12mm, 13mm, 14mm or 15mm.

[0032] Preferably, the average diameter of the air extraction holes in the bottom liner is 6-6.5 mm, for example, it can be 6 mm, 6.1 mm, 6.2 mm, 6.3 mm, 6.4 mm or 6.5 mm, etc.

[0033] Preferably, the bottom liner has a cylindrical structure, wherein the distribution density of the air extraction holes along the circumferential direction of the bottom liner is 7° / hole to 8° / hole, for example, it can be 7° / hole, 7.5° / hole or 8° / hole, etc.

[0034] This invention synergistically limits the average pore size and distribution density of the air extraction holes in the bottom liner, which helps to enhance the cleaning ability of the bottom space of the inner cavity and realize the airflow field and dead-angle-free cleaning of the cavity body from top to bottom. If the above requirements are not met, the uniformity of cleaning will be affected.

[0035] Preferably, the diameter of the vent holes in the top liner is the same as the diameter of the vent holes in the bottom liner.

[0036] Preferably, the distribution density of the air extraction holes in the top liner is the same as the distribution density of the air extraction holes in the bottom liner.

[0037] Preferably, the arrangement of the air extraction holes in the top liner is staggered from the arrangement of the air extraction holes in the bottom liner.

[0038] Preferably, the distance between the lower surface of the spray head and the upper surface of the movable heater is adjustable in the range of 8-30mm, for example, it can be 8mm, 10mm, 15mm, 20mm, 25mm or 30mm.

[0039] It should be noted that the movable heater can move up and down within the inner cavity. The range of movement depends on the process requirements and can be adjusted according to the actual situation. It is not limited to the spacing adjustment range specified above. The spacing adjustment range mainly depends on the position of the air extraction holes of the top and bottom linings.

[0040] In a second aspect, the present invention provides a cleaning method for a PECVD cavity kit, wherein the cleaning method is performed in accordance with the remote plasma cleaning method for the PECVD cavity kit described in the first aspect, and includes the following steps:

[0041] Clean gas is introduced into the remote plasma source for activation, and the clean gas is activated into a plasma state before being transported into the cavity body.

[0042] The plasma-state cleaning gas is distributed into the interior of the cavity through the spray head; the movable heater is activated and controlled to move along the thickness direction of the liner assembly to perform step-by-step cleaning. The steps include: moving to the first cleaning position to clean the upper area of ​​the interior cavity, and then moving down to the second cleaning position to clean the entire interior cavity.

[0043] After cleaning is completed, the remote plasma source is turned off, the mobile heater is lowered to the bottom of the inner cavity, and exhaust is used to purge the entire cavity body.

[0044] The PECVD chamber cleaning process provided by this invention has excellent uniformity and stability, uniform gas flow field, and achieves more efficient chamber cleaning, reducing chamber particulate contamination.

[0045] This invention employs a step-by-step cleaning method, which not only significantly improves overall cleaning efficiency and shortens cleaning time, but also achieves a more uniform gas flow field, thereby enabling more efficient chamber cleaning, reducing chamber particulate contamination, and helping to extend the service life of the chamber components.

[0046] It should be noted that cleaning gases and cleaning products are continuously discharged during the cleaning process.

[0047] Preferably, the cleaning gas includes any one or a combination of at least two of NF3, C3F8, C2F6 or CF4.

[0048] Preferably, during the activation process, the working gas pressure range is 0.5-5 Torr, for example, it can be 0.5 Torr, 1 Torr, 2 Torr, 3 Torr, 4 Torr or 5 Torr, etc.

[0049] It should be noted that the laser power of the remote plasma source is not specifically limited. The optimal operating power is automatically matched according to the flow of the incoming cleaning gas, and the maximum power can reach 10kW.

[0050] Preferably, the flow rate of the clean gas in the plasma state is 1-8 slm, for example, it can be 1 slm, 2 slm, 3 slm, 4 slm, 5 slm, 6 slm, 7 slm or 8 slm, etc.

[0051] Preferably, the first cleaning position is located in the top liner and below the air extraction hole structure in the top liner.

[0052] In this invention, when the first cleaning position is in the above-mentioned position, the cleaning gas will flow directly out from the air extraction hole, which helps to reduce the obstruction of airflow and improve the cleaning effect.

[0053] Preferably, the second cleaning position is located in the bottom liner and below the air extraction hole structure in the bottom liner.

[0054] In this invention, when the second cleaning position is in the above-mentioned position, the cleaning gas will flow directly out from the air extraction hole, which helps to reduce the obstruction of airflow and improve the cleaning effect.

[0055] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] This invention achieves a more efficient chamber cleaning effect by constructing a coordinated air extraction hole combination structure with uniformly distributed rows of air extraction holes in the top and bottom linings, and coordinating with the position of the movable heater. This design not only overcomes the problem of uneven airflow caused by traditional side air intake or single-point air extraction, which is beneficial to improving the uniformity and stability of the PECVD chamber cleaning process, but also enhances the cleaning effect of each area of ​​the chamber in stages by adjusting the position of the movable heater, which greatly improves the cleaning efficiency and reduces chamber particulate contamination. Thus, it effectively extends the maintenance cycle of the chamber while increasing equipment capacity. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the structure of the remote plasma cleaning PECVD cavity kit provided in Embodiment 1 of the present invention.

[0059] Figure 2 This is a top-down view of the simulated surface cleaning gas flow rate of the mobile heater when the PECVD cavity kit for remote plasma cleaning provided in Example 1 is used for cleaning.

[0060] Figure 3 This is a simulated cross-sectional diagram of the surface cleaning gas flow rate of the mobile heater when the PECVD cavity kit for remote plasma cleaning provided in Example 1 is used for cleaning.

[0061] Figure 4This is a top-down view of the simulated surface cleaning gas flow rate of the mobile heater when the PECVD cavity kit for remote plasma cleaning provided in Example 1 is used for cleaning.

[0062] Figure 5 This is a simulated cross-sectional diagram of the surface cleaning gas flow rate when the mobile heater is at Gap=8mm during cleaning using the remote plasma cleaning PECVD cavity kit provided in Example 1 of this invention.

[0063] Figure 6 A top-down view simulating the flow rate of the surface cleaning gas at Gap=30mm when using the remote plasma cleaning PECVD chamber kit provided in Comparative Example 1.

[0064] Figure 7 Simulated cross-sectional view of the surface cleaning gas flow rate at Gap=30mm when using the remote plasma cleaning PECVD chamber kit provided in Comparative Example 1.

[0065] Among them, 1-cavity body; 11-outer cavity; 12-inner cavity; 2-remote plasma source; 3-spray head; 4-liner assembly; 41-top liner; 42-bottom liner; 5-extraction port; 6-movable heater; 7-vacuum pump. Detailed Implementation

[0066] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0067] The scope of this invention can be defined by lower and upper limits. The selected lower and upper limits define the boundaries of a specific range. The range defined in this way can be defined by the inclusion or exclusion of endpoints. Any endpoint can be independently selected for inclusion or exclusion, and all lower and upper limits can be arbitrarily combined to form new ranges. That is, any lower limit can be combined with any upper limit to form an effective range. For example, if the ranges of 60~120 and 80~110 are listed for specific parameters, it should be understood that the ranges of 60~110 and 80~120 also fall within the scope of this invention. In addition, if the minimum range values ​​1 and 2 are listed, and the maximum range values ​​3, 4 and 5 are also listed, then all ranges of 1~3, 1~4, 1~5, 2~3, 2~4 and 2~5 fall within the scope of this invention. In this invention, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0~5" means that all real numbers between 0 and 5 have been fully listed in this document, and "0~5" is only a shortened representation of this set of numerical combinations. When a parameter is expressed as an integer ≥2, it is equivalent to listing positive integers that meet the requirements, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. When a parameter is expressed as an integer selected from "2~10", it is equivalent to listing any integer among 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0068] In this invention, "a combination of at least two" refers to a quantity greater than or equal to 2 unless otherwise specified. For example, "any one or a combination of at least two" means that any one of the listed items can be selected, or a combination of at least two of the listed items formed in a manner that does not conflict and enables the implementation of this invention. In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" cover any one of two or more related listed items, as well as any and all combinations of the related listed items. The arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" means a set consisting of A, B, and combinations of A and B, where "containing A and / or B" can be understood, depending on the context of the statement, as containing A, containing B, or simultaneously containing both A and B. In this invention, "optional" means that the corresponding feature, component, step or solution is not necessary, that is, it is selected from either "with" or "without". If there are multiple "optional" limitations in a technical solution, unless otherwise specified and there is no technical conflict or mutual constraint, each "optional" limitation is independent and does not affect the others.

[0069] In this invention, technical features or solutions described using open-ended terms such as "comprising" or "including" do not exclude additional non-conflicting elements beyond the listed elements unless otherwise specified. They are considered to disclose both closed-ended features or solutions consisting solely of the listed elements and open-ended features or solutions that may include additional non-conflicting elements beyond the listed elements. For example, if A includes a1, a2, and a3, unless otherwise specified, this means that A can consist only of a1, a2, and a3, or it can include other non-conflicting elements based on a1, a2, and a3. This corresponds to the disclosure of technical solutions such as "A consists of a1, a2, and a3," "A is selected from a1, a2, and a3," and "A not only includes a1, a2, and a3, but may also include other non-conflicting elements." All embodiments and optional embodiments of this invention, unless otherwise specified and without technical conflict, can be combined to form new technical solutions, and such combinations fall within the scope of this invention. The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various locations throughout the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will understand, explicitly and implicitly, that the embodiments described in this invention can be combined with other embodiments that do not conflict with the technology. The ordinal numbers "first," "second," "third," and "fourth," etc., used in the expressions "first aspect," "second aspect," "third aspect," and "fourth aspect" in this invention are for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly specifying the importance or quantity of the indicated technical features. They serve only as a non-exhaustive enumeration and do not constitute a closed limitation on quantity.

[0070] In this invention, the order in which the steps are written in the methods described in each embodiment does not imply a strict execution order. The actual execution order of each step should be determined based on its function and possible internal logic. Unless otherwise specified, all steps of this invention can be executed in the order they are written, or in any order without technical conflict. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) executed sequentially, or it may include steps (b) and (a) executed sequentially. If the method also includes step (c), then step (c) can be added to the method in any order without conflict, including but not limited to the execution order of steps (a), (b), and (c), steps (a), (c), and (b), steps (c), (a), and (b), etc.

[0071] Example 1

[0072] This embodiment provides a remote plasma cleaning PECVD chamber kit, and a schematic diagram of the structure of the remote plasma cleaning PECVD chamber kit is shown below. Figure 1 As shown, it includes:

[0073] The cavity body 1 includes an outer cavity 11 and an inner cavity 12 nested within the outer cavity 11.

[0074] The remote plasma source 2 is connected to the cavity body 1 and is used to activate the introduced clean gas and deliver it into the cavity body 1.

[0075] The spray head 3 is located in the upper space between the outer cavity 11 and the inner cavity 12, and is used to distribute the activated cleaning gas into the interior of the inner cavity 12.

[0076] The liner assembly 4 includes a top liner 41 and a bottom liner 42 stacked along a direction away from the spray head 3; the top liner 41 and the bottom liner 42 are respectively provided with a row of uniformly distributed air extraction holes for outputting clean gas; the air extraction hole structure is a single row of air extraction holes 5; the liner assembly 4 and the inner cavity 12 together define an air extraction channel for discharging the cleaned gas to the outside of the cavity body 1; the opening of the air extraction channel is opened on the side wall of the inner cavity 12.

[0077] A movable heater 6 is embedded in the liner assembly 4 and is used to move along the vertical direction of the liner assembly 4 to adapt to the cleaning needs of different positions of the cavity body 1.

[0078] Vacuum pump 7, which is connected to the air extraction channel through a pipeline, is used to extract the cleaning gas and cleaning products in the inner cavity 12 and the air extraction channel to the outside of the cavity during the cleaning process.

[0079] The remote plasma source 2 operates at a pressure range of 0.5-5 Torr; the spray head 3 has a porous structure with an average aperture of 1.4 mm and an average spacing of 3.2 mm; the exhaust vents in the top liner 41 are distributed in the middle region of the top liner 41; the top liner 41 has a height of 13 mm and is a cylindrical structure, wherein the exhaust vents 5 have an average aperture of 6.35 mm and a distribution density of 7.5 vents per circumference along the top liner 41; the bottom... The air extraction holes in the liner 42 are distributed in the middle area of ​​the bottom liner 42; the bottom liner 42 has a height of 13mm and is a cylindrical structure, wherein the average diameter of the air extraction holes 5 is 6.35mm, and the distribution density of the air extraction holes 5 along the circumferential direction of the bottom liner 42 is 7.5° / hole; the arrangement of the air extraction holes 5 in the top liner 41 is staggered from the arrangement of the air extraction holes 5 in the bottom liner 42; the distance between the lower surface of the spray head 3 and the upper surface of the movable heater 6 can be adjusted from 8 to 30mm.

[0080] This embodiment also provides a cleaning method for the above-mentioned PECVD cavity kit. The cleaning method is performed in the above-mentioned remote plasma cleaning PECVD cavity kit and includes the following steps:

[0081] Stop the deposition process and shut down all reactive gas sources.

[0082] Evacuate the vacuum and purge with nitrogen.

[0083] NF3 is provided as a cleaning gas.

[0084] The cleaning gas is introduced into a remote plasma source for activation, and the cleaning gas is activated into a plasma state. Then, the cleaning gas in the plasma state is delivered into the cavity body at a flow rate of 5 slm. During the activation process, the working gas pressure range is 0.5-5 Torr.

[0085] The plasma-state cleaning gas is distributed into the interior cavity through a spray head; the movable heater is activated and controlled to move along the thickness direction of the liner assembly for step-by-step cleaning. The steps include: moving to a first cleaning position to clean the upper area of ​​the interior cavity through the single-row exhaust hole structure of the top liner, and then moving down to a second cleaning position to clean the entire interior cavity through the single-row exhaust hole structures of the top and bottom liners; wherein, the first cleaning position is located in the top liner and below the exhaust hole structure in the top liner, and the movable heater does not block the exhaust holes, so that the gap between the lower surface of the spray head and the upper surface of the movable heater is 8 mm; the second cleaning position is located in the bottom liner and below the exhaust hole structure in the bottom liner, and the movable heater does not block the exhaust holes, so that the gap between the lower surface of the spray head and the upper surface of the movable heater is 30 mm.

[0086] After cleaning is completed, the remote plasma is shut off, the mobile heater is lowered to the bottom of the inner cavity, and exhaust is used to purge the entire cavity body.

[0087] Figure 2 and Figure 3 The diagrams show a top view and a cross-sectional view of the simulated flow velocity of the cleaning gas at a surface gap of 30 mm when using the remote plasma cleaning PECVD chamber kit provided in this embodiment. Figure 2 and Figure 3 (1) is a simulation diagram of the surface cleaning gas flow rate of the mobile heater in the left region when Gap=30mm. Figure 2 and Figure 4 (2) is a simulation diagram of the cleaning gas flow rate on the surface of the mobile heater in the right region when Gap=30mm. As can be seen from the diagram, under the combined condition of the two rows of extraction holes, the gas distribution in the space above the mobile heater is more uniform, and the velocity difference is smaller, thus achieving efficient cleaning of the bottom region of the cavity. Furthermore, when Gap=30mm, the surface of the mobile heater is exposed above the upper edge of the wafer transport channel (not shown), allowing the cleaning gas to enter the transport channel and clean the transport channel and other parts.

[0088] Figure 4 and Figure 5 The following diagrams show the simulated top view and simulated cross-sectional view of the surface cleaning gas flow rate when the mobile heater is at a gap of 8 mm during cleaning using the remote plasma cleaning PECVD cavity kit provided in Example 1. Figure 4 and Figure 5 (1) is a simulation diagram of the surface cleaning gas flow rate of the mobile heater in the left region when Gap=8mm. Figure 4 and Figure 5 (2) is a simulation diagram of the gas flow rate on the surface of the mobile heater in the right region when Gap=8mm. When Gap=8mm, the surface of the mobile heater just does not block the exhaust hole of the top liner, so the Gap spacing should not be too small. Flow rate simulation top view ( Figure 2 The display shows that in this state, the movable heater makes the gas distribution in the upper space more uniform, ensuring that the cleaning gas and cleaning by-products can be efficiently extracted, and can achieve efficient cleaning of the upper part of the cavity.

[0089] Example 2

[0090] This embodiment provides a remote plasma cleaning PECVD chamber kit, which includes:

[0091] The cavity body includes an outer cavity and an inner cavity nested within the outer cavity.

[0092] A remote plasma source, connected to the cavity body, is used to activate the introduced clean gas and deliver it into the cavity body.

[0093] A spray head is disposed in the upper space between the outer cavity and the inner cavity, and is used to distribute the activated cleaning gas into the interior of the inner cavity.

[0094] The liner assembly includes a top liner and a bottom liner stacked along a direction away from the spray head; the top liner and the bottom liner are respectively provided with a row of uniformly distributed air extraction holes for outputting clean gas; the air extraction hole structure is a single row of air extraction holes 5; the liner assembly and the inner cavity together define an air extraction channel for discharging the cleaned gas to the outside of the cavity body; the opening of the air extraction channel is opened on the side wall of the inner cavity.

[0095] A movable heater, embedded in the liner assembly, is used to move along the vertical direction of the liner assembly to adapt to the cleaning needs of different positions of the cavity body.

[0096] A vacuum pump, which is connected to the air extraction channel via a pipeline, is used to extract the cleaning gas and cleaning products from the inner cavity and the air extraction channel to the outside of the cavity during the cleaning process.

[0097] The remote plasma source operates at a pressure range of 0.5-5 Torr; the spray head has a porous structure with an average aperture of 1.4 mm and an average spacing of 3.2 mm; the exhaust vents in the top liner are distributed in the middle region of the top liner; the top liner has a height of 13 mm and is cylindrical, with an average aperture of 6 mm for the exhaust vents and a circumferential density of 7 vents per vent; the bottom liner has exhaust vents distributed in the middle region of the bottom liner; the bottom liner has a height of 13 mm and is cylindrical, with an average aperture of 6 mm for the exhaust vents and a circumferential density of 8 vents per vent; the arrangement of the exhaust vents in the top liner is staggered from that in the bottom liner; the distance between the lower surface of the spray head and the upper surface of the movable heater is adjustable from 8 to 30 mm.

[0098] This embodiment also provides a cleaning method for the above-mentioned PECVD cavity kit. The cleaning method is performed in the above-mentioned remote plasma cleaning PECVD cavity kit and includes the following steps:

[0099] Stop the deposition process and shut down all reactive gas sources.

[0100] Evacuate the vacuum and purge with nitrogen.

[0101] C3F8 is provided as a cleaning gas.

[0102] The cleaning gas is introduced into a remote plasma source for activation, and the cleaning gas is activated into a plasma state. Then, the cleaning gas in the plasma state is delivered into the cavity body at a flow rate of 1 slm. During the activation process, the working gas pressure range is 0.5-5 Torr.

[0103] The plasma-state cleaning gas is distributed into the interior cavity through a spray head; the movable heater is activated and controlled to move along the thickness direction of the liner assembly for step-by-step cleaning. The steps include: moving to a first cleaning position to clean the upper area of ​​the interior cavity through the single-row exhaust hole structure of the top liner, and then moving down to a second cleaning position to clean the entire interior cavity through the single-row exhaust hole structures of the top and bottom liners; wherein, the first cleaning position is located in the top liner and below the exhaust hole structure in the top liner, and the movable heater does not block the exhaust holes, so that the gap between the lower surface of the spray head and the upper surface of the movable heater is 8 mm; the second cleaning position is located in the bottom liner and below the exhaust hole structure in the bottom liner, and the movable heater does not block the exhaust holes, so that the gap between the lower surface of the spray head and the upper surface of the movable heater is 30 mm.

[0104] After cleaning is completed, the remote plasma is shut off, the mobile heater is lowered to the bottom of the inner cavity, and exhaust is used to purge the entire cavity body.

[0105] Example 3

[0106] This embodiment provides a remote plasma cleaning PECVD chamber kit, which includes:

[0107] The cavity body includes an outer cavity and an inner cavity nested within the outer cavity.

[0108] A remote plasma source, connected to the cavity body, is used to activate the introduced clean gas and deliver it into the cavity body.

[0109] A spray head is disposed in the upper space between the outer cavity and the inner cavity, and is used to distribute the activated cleaning gas into the interior of the inner cavity.

[0110] The liner assembly includes a top liner and a bottom liner stacked along a direction away from the spray head; the top liner and the bottom liner are respectively provided with a row of uniformly distributed air extraction holes for outputting clean gas; the air extraction hole structure is a single row of air extraction holes; the liner assembly and the inner cavity together define an air extraction channel for discharging the cleaned gas to the outside of the cavity body; the opening of the air extraction channel is opened on the side wall of the inner cavity.

[0111] A movable heater, embedded in the liner assembly, is used to move along the vertical direction of the liner assembly to adapt to the cleaning needs of different positions of the cavity body.

[0112] A vacuum pump, which is connected to the air extraction channel via a pipeline, is used to extract the cleaning gas and cleaning products from the inner cavity and the air extraction channel to the outside of the cavity during the cleaning process.

[0113] The remote plasma source operates at a pressure range of 0.5-5 Torr; the spray head has a porous structure with an average aperture of 1.4 mm and an average aperture spacing of 3.2 mm; the exhaust vents in the top liner are distributed in the middle region of the top liner; the top liner has a height of 13 mm and is a cylindrical structure, wherein the average aperture of the exhaust vents is 6.5 mm, and the exhaust vents are distributed at a density of 8° / vent along the circumference of the top liner; the exhaust vents in the bottom liner are distributed in the middle region of the bottom liner; the bottom liner has a height of 13 mm and is a cylindrical structure, wherein the average aperture of the exhaust vents is 6.5 mm, and the exhaust vents are distributed at a density of 8° / vent along the circumference of the bottom liner; the arrangement of the exhaust vents in the top liner is staggered from that in the bottom liner; the distance between the lower surface of the spray head and the upper surface of the movable heater is adjustable from 8-30 mm.

[0114] This embodiment also provides a cleaning method for the above-mentioned PECVD cavity kit. The cleaning method is performed in the above-mentioned remote plasma cleaning PECVD cavity kit and includes the following steps:

[0115] Stop the deposition process and shut down all reactive gas sources.

[0116] Evacuate the vacuum and purge with nitrogen.

[0117] NF3 is provided as a cleaning gas.

[0118] The cleaning gas is introduced into a remote plasma source for activation, and the cleaning gas is activated into a plasma state. Then, the cleaning gas in the plasma state is delivered into the cavity body at a flow rate of 8 slm. During the activation process, the working gas pressure range is 0.5-5 Torr.

[0119] The plasma-state cleaning gas is distributed into the interior cavity through a spray head; the movable heater is activated and controlled to move along the thickness direction of the liner assembly for step-by-step cleaning. The steps include: moving to a first cleaning position to clean the upper area of ​​the interior cavity through the single-row exhaust hole structure of the top liner, and then moving down to a second cleaning position to clean the entire interior cavity through the single-row exhaust hole structures of the top and bottom liners; wherein, the first cleaning position is located in the top liner and below the exhaust hole structure in the top liner, and the movable heater does not block the exhaust holes, so that the gap between the lower surface of the spray head and the upper surface of the movable heater is 8mm; the second cleaning position is located in the bottom liner and below the exhaust hole structure in the bottom layer, and the movable heater does not block the exhaust holes, so that the gap between the lower surface of the spray head and the upper surface of the movable heater is 30mm.

[0120] After cleaning is completed, the remote plasma is shut off, the mobile heater is lowered to the bottom of the inner cavity, and exhaust is used to purge the entire cavity body.

[0121] Example 4

[0122] The only difference between this embodiment and Embodiment 1 is that the average diameter of the air extraction holes in the bottom liner is 6.5 mm, and the diameter of the air extraction holes in the top liner is smaller than the diameter of the air extraction holes in the bottom liner.

[0123] Example 5

[0124] The only difference between this embodiment and Embodiment 1 is that the distribution density of the air extraction holes in the bottom liner is 10° / hole, and the distribution density of the air extraction holes in the top liner is not equal to the distribution density of the air extraction holes in the bottom liner.

[0125] Comparative Example 1

[0126] The only difference between this comparative example and Example 1 is that the bottom liner does not have a single row of air extraction holes.

[0127] Figure 6 and Figure 7 The diagrams show a top view and a cross-sectional view of the simulated flow velocity of the surface cleaning gas at a gap of 30 mm when using the remote plasma cleaning PECVD chamber kit provided in Comparative Example 1. Figure 6 and Figure 7 (1) is a simulation diagram of the surface cleaning gas flow rate of the mobile heater in the left region when Gap=30mm. Figure 6 and Figure 7(2) is a simulation diagram of the gas flow rate on the surface of the mobile heater in the right region when Gap = 30mm. As shown in the diagram, the gas distribution in the space above the mobile heater is extremely uneven, and the greater the distance between the mobile heater and the upper exhaust port, the greater the unevenness of the gas flow rate distribution and the larger the velocity difference, resulting in a worse cleaning effect in the bottom region of the cavity, especially in areas with smaller velocity distribution. Therefore, combined with... Figure 2-3 and Figure 6-7 Simulation results show that the closer to the vent hole, the more uniform the gas velocity distribution and the smaller the velocity difference, which is more conducive to the cleaning effect of the cavity. Therefore, in this application, when Gap=30mm, another row of vent holes is opened near the top of the mobile heater (i.e., a row of vent holes is opened in the bottom liner), which has a better cleaning effect on the lower part of the cavity than a single row of holes.

[0128] Performance testing

[0129] (a) Repeatability testing

[0130] First, a SiO2 thin film is deposited in the PECVD chamber. Then, the cleaning method shown in the examples and comparative examples is run for cleaning. After that, one clean wafer is selected at each of the two predicted positions in the chamber for particle testing on the front side of the wafer. This process of "deposition-cleaning-particle testing" is recorded as one cycle. The process is repeated three times. The number of particles with a size greater than or equal to 0.09 μm is recorded and the average value is taken.

[0131] (ii) Stability test

[0132] Every week, particle detection is performed on the cavity particles. Six clean wafers are selected for front-side particle testing. The stability of the cavity particles is observed for four consecutive weeks, and the average number of particles with a size greater than or equal to 0.09μm is calculated each week.

[0133] The results are shown in Table 1.

[0134] Table 1

[0135]

[0136] analyze:

[0137] As shown in Table 1, particles with a size greater than or equal to 0.09 μm are considered critical defect particles in PECVD coating. These particles can directly lead to serious yield problems such as thin film pinholes, poor step coverage, device leakage, and even short circuits. They are high-risk sources of contamination that must be strictly controlled in semiconductor manufacturing.

[0138] A comparison of Examples 1 and 4 shows that if the diameter of the air extraction hole in the top liner is smaller than that in the bottom liner, the number of particles on the front increases from 7 to 11 in the repeatability test, and the number of particles increases significantly in each week of the stability test (e.g., from 8 to 13 in the fourth week). The cleaning effect decreases significantly. This means that the inconsistent diameter of the air extraction holes in the upper and lower layers will lead to uneven airflow speed, incomplete local cleaning, and an increase in residual particles.

[0139] A comparison of Examples 1 and 5 shows that if the distribution density of the air extraction holes in the top liner is not equal to the distribution density of the air extraction holes in the bottom liner, the number of particles on the front increases from 7 to 9 in the repeatability test, and the number of particles in each week increases significantly in the stability test (from 8 to 14 in the fourth week). This indicates that the difference in distribution density will disrupt the uniformity of air extraction through the air extraction holes, causing airflow deviation, and the cleaning gas cannot effectively clean the entire inner cavity, increasing the risk of particulate contamination.

[0140] As can be seen from the comparison between Example 1 and Comparative Example 1, if there is no single-row venting structure in the bottom liner, the number of particles on the front in the repeatability test is as high as 13, and the number of particles in each week of the stability test exceeds 11, and even reaches 17 in the fourth week. This shows that relying solely on the single-row venting of the top liner cannot form an effective venting channel. The residual gas and by-products after cleaning accumulate in the cavity, resulting in serious particulate contamination.

[0141] In summary, this invention achieves a more efficient chamber cleaning effect by setting single-row air extraction hole structures in the top and bottom linings respectively, constructing a combined structure of double-row air extraction holes, and coordinating with the position of the movable heater. This design not only overcomes the problem of uneven airflow caused by traditional side air intake or single-point air extraction, which is beneficial to improving the uniformity and stability of the PECVD chamber cleaning process, but also enhances the cleaning effect of each area of ​​the chamber in stages by adjusting the position of the movable heater, greatly improving cleaning efficiency and reducing chamber particulate contamination. Thus, it effectively extends the maintenance cycle of the chamber while increasing equipment capacity.

[0142] It should be noted that the present invention is illustrated through the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A remote plasma cleaning PECVD cavity kit, characterized in that, The remote plasma cleaning PECVD cavity kit includes: The cavity body includes an outer cavity and an inner cavity nested within the outer cavity; A remote plasma source, connected to the cavity body, is used to activate the introduced clean gas and deliver it into the cavity body; A spray head is disposed in the upper space between the outer cavity and the inner cavity, and is used to distribute the activated cleaning gas into the interior of the inner cavity; The liner assembly includes a top liner and a bottom liner stacked along a direction away from the spray head; the top liner and the bottom liner are respectively provided with a uniformly distributed row of air extraction holes for outputting clean gas; the liner assembly and the inner cavity together define an air extraction channel for discharging the cleaned gas to the outside of the cavity body. A movable heater, embedded in the liner assembly, is used to move along the vertical direction of the liner assembly to adapt to the cleaning needs of different positions of the cavity body.

2. The remote plasma cleaning PECVD cavity kit according to claim 1, characterized in that, The air extraction hole structure includes at least one row of air extraction holes.

3. The remote plasma cleaning PECVD cavity kit according to claim 1, characterized in that, The remote plasma cleaning PECVD chamber kit also includes a vacuum pump, which is connected to the evacuation channel via a pipeline.

4. The remote plasma cleaning PECVD chamber kit according to claim 2, characterized in that, The air extraction channel opening is located on the side wall or bottom of the inner cavity; And / or, the venting structure in the top liner is distributed in the middle region of the top liner; And / or, the height of the top liner is 10-15 mm; And / or, the average diameter of the vent holes in the top liner is 6-6.5 mm; And / or, the top liner is a cylindrical structure, wherein the distribution density of the air extraction holes along the circumferential direction of the top liner is 7° / hole to 8° / hole.

5. The remote plasma cleaning PECVD cavity kit according to claim 1, characterized in that, The air extraction hole structure in the bottom liner is distributed in the middle area of ​​the bottom liner; And / or, the height of the bottom liner is 10-15 mm; And / or, the average diameter of the vent holes in the bottom liner is 6-6.5 mm; And / or, the bottom liner is a cylindrical structure, wherein the distribution density of the air extraction holes along the circumferential direction of the bottom liner is 7° / hole to 8° / hole.

6. The remote plasma cleaning PECVD cavity kit according to claim 1, characterized in that, The diameter of the air extraction hole in the top liner is the same as the diameter of the air extraction hole in the bottom liner. And / or, the distribution density of the vent holes in the top liner is the same as the distribution density of the vent holes in the bottom liner; And / or, the arrangement of the air extraction holes in the top liner is vertically offset from the arrangement of the air extraction holes in the bottom liner.

7. The remote plasma cleaning PECVD cavity kit according to claim 1, characterized in that, The distance between the lower surface of the spray head and the upper surface of the movable heater can be adjusted from 8 to 30 mm.

8. A cleaning method for a PECVD cavity kit, characterized in that, The cleaning method is performed in the remote plasma cleaning PECVD cavity kit according to any one of claims 1-7, and includes the following steps: Clean gas is introduced into the remote plasma source for activation, the clean gas is activated into a plasma state, and then transported into the cavity body; The plasma-state cleaning gas is distributed into the interior of the cavity through the spray head; the movable heater is activated and controlled to move along the thickness direction of the liner assembly to perform step-by-step cleaning. The steps include: moving to the first cleaning position to clean the upper area of ​​the interior cavity, and then moving down to the second cleaning position to clean the entire interior cavity. After cleaning is completed, the remote plasma source is turned off, the mobile heater is lowered to the bottom of the inner cavity, and exhaust is used to purge the entire cavity body.

9. The cleaning method according to claim 8, characterized in that, The cleaning gas includes any one or a combination of at least two of NF3, C3F8, C2F6 or CF4; And / or, during the activation process, the working gas pressure range is 0.5-5 Torr; And / or, the flow rate of the clean gas in the plasma state is 1-8 slm.

10. The cleaning method according to claim 8, characterized in that, The first cleaning position is located in the top liner and below the air extraction hole structure in the top liner; And / or, the second cleaning position is located in the bottom liner and below the air extraction hole structure in the bottom liner.

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