Cleaning system and cleaning method for chemical vapor deposition apparatus

Abstract

The disclosure provides a cleaning system and a cleaning method for a chemical vapor deposition device. The system comprises a reaction chamber, a gas inlet located at the top of the reaction chamber, a first gas path, a first end of the first gas path being in communication with a remote plasma source located outside the reaction chamber to receive a fluorine-containing free radical gas from the remote plasma source, a second end of the first gas path being in communication with the gas inlet to deliver the fluorine-containing free radical gas into the reaction chamber, a heating table located inside the reaction chamber, a second gas path, a first end of the second gas path being in communication with an external gas cabinet module to receive oxygen from the external gas cabinet module, a second end of the second gas path being arranged at the bottom of the reaction chamber, below the heating table, and being in communication with the reaction chamber to deliver the oxygen into the reaction chamber, and the amount of oxygen delivered by the second gas path accounts for 5% to 15% of the total amount of gas delivered by the first gas path and the second gas path. The above technical solution can improve the cleanliness of the chemical vapor deposition device.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor equipment, and more particularly to a cleaning system and cleaning method for a chemical vapor deposition (CVD) apparatus. Background Technology

[0002] In semiconductor manufacturing processes, chemical vapor deposition (CVD) is one of the core technologies for preparing dielectric thin films. Among them, sub-atmospheric chemical vapor deposition (SACVD) is widely used in key processes such as shallow trench isolation filling and interlayer dielectric layer deposition due to its excellent trench filling capability and film quality.

[0003] However, in chemical vapor deposition (CVD) equipment, byproducts (such as unreacted precursors and reactive polymers) tend to accumulate in "dead zones" where airflow is difficult to achieve sufficient circulation, such as the edges of the spray nozzles, the bottom of the heating stage, and the transport channels within the reaction chamber. These residues not only contaminate the wafer surface and reduce product yield, but also cause process parameter drift, affecting the stability and repeatability of equipment operation.

[0004] Therefore, how to provide technical solutions to improve the cleanliness of chemical vapor deposition equipment has become an urgent technical problem to be solved. Summary of the Invention

[0005] In view of this, the present disclosure provides a cleaning system and cleaning method for a chemical vapor deposition (CVD) apparatus, which can improve the cleanliness of the CVD apparatus.

[0006] This disclosure provides a cleaning system for a chemical vapor deposition (CVD) apparatus, comprising: a reaction chamber; an air inlet located at the top of the reaction chamber; a first gas path, a first end of which is connected to a remote plasma source located outside the reaction chamber to receive fluorine-containing free radical gas from the remote plasma source, the fluorine-containing free radical gas being obtained by the remote plasma source from the initial gas received from an external gas holder module after post-processing; a second end of the first gas path being connected to the air inlet to deliver the fluorine-containing free radical gas into the reaction chamber; a heating stage located inside the reaction chamber; a second gas path, a first end of which is connected to the external gas holder module to receive oxygen from the external gas holder module; a second end of the second gas path being located at the bottom of the reaction chamber and below the heating stage, connected to the reaction chamber to deliver the oxygen into the reaction chamber; wherein the amount of oxygen introduced into the second gas path accounts for 5% to 15% of the total amount of gas introduced into the first and second gas paths.

[0007] Optionally, the cleaning system further includes: a third gas path; a first end of the third gas path is connected to an external gas holder module to receive nitrogen trifluoride from the external gas holder module; and a second end of the third gas path is connected to the remote plasma source to deliver the nitrogen trifluoride to the remote plasma source.

[0008] Optionally, the cleaning system further includes: a fourth gas path; a first end of the fourth gas path is connected to an external gas holder module to receive oxygen from the external gas holder module; a second end of the fourth gas path is connected to the remote plasma source to supply the oxygen to the remote plasma source; wherein the total amount of oxygen input through the fourth gas path and oxygen introduced through the second gas path accounts for 5% to 20% of the total amount of gas introduced into the reaction chamber through the first gas path and the second gas path.

[0009] Optionally, the amount of oxygen input through the fourth gas path is greater than the amount of oxygen input through the second gas path.

[0010] Optionally, both the fourth gas path and the second gas path are connected to the external gas holder module; the external gas holder module is used to provide various gases and control gas flow and on / off.

[0011] Optionally, the heating platform can be raised and lowered vertically; in the second air path, the amount of oxygen introduced when the heating platform is at the first height is less than the amount of oxygen introduced when the heating platform is at the second height; the first height is less than the second height.

[0012] Optionally, the second end of the second gas path is provided with a plurality of gas outlets, which are located at the bottom of the reaction chamber and are evenly distributed along the circumference of the heating platform.

[0013] This disclosure also provides a cleaning method for a chemical vapor deposition apparatus, applied to the cleaning system described in any of the above claims, comprising: dissociating a fluorine-containing gas using a remote plasma source to generate a fluorine-containing free radical gas; conveying the fluorine-containing free radical gas to the top of a reaction chamber via a first gas path and an inlet; and introducing oxygen into the area below the heating stage at the bottom of the reaction chamber via a second gas path, wherein the amount of oxygen introduced accounts for 5% to 15% of the total amount of gas introduced via the first and second gas paths.

[0014] Optionally, the duration for which oxygen is introduced into the second gas path is less than or equal to the duration for which the fluorine-containing free radical gas is introduced.

[0015] Optionally, the method includes: an external gas holder module for providing various gases and controlling gas flow and on / off; and a third gas path and a fourth gas path, both connected to the external gas holder module and the remote plasma source; before dissociating the fluorine-containing gas through the remote plasma source, the method includes: inputting nitrogen trifluoride gas into the remote plasma source through the third gas path; inputting oxygen into the remote plasma source through the fourth gas path; wherein the nitrogen trifluoride gas input through the third gas path and the oxygen input through the fourth gas path are mixed in the remote plasma source; the total amount of oxygen input through the fourth gas path and oxygen introduced through the second gas path accounts for 5% to 20% of the total amount of gas introduced through the first gas path and the second gas path.

[0016] Compared with the prior art, the technical solution of the present disclosure has the following advantages: The cleaning system and cleaning method for a chemical vapor deposition (CVD) apparatus provided in this disclosure include: a reaction chamber; an air inlet located at the top of the reaction chamber; a first gas path, the first end of which is connected to a remote plasma source located outside the reaction chamber to receive fluorine-containing free radical gas from the remote plasma source; the second end of the first gas path is connected to the air inlet to deliver fluorine-containing free radical gas into the reaction chamber; a heating stage located inside the reaction chamber; a second gas path, the first end of which is connected to an external gas holder module to receive oxygen from the external gas holder module; the second end of the second gas path is located at the bottom of the reaction chamber and below the heating stage, and is connected to the reaction chamber to deliver oxygen into the reaction chamber; the amount of oxygen introduced into the second gas path accounts for 5% to 15% of the total amount of gas introduced into the first and second gas paths. By decoupling the second gas path to an external gas holder module and positioning its inlet at the bottom of the reaction chamber below the heating stage, precise directional oxygen delivery can be achieved, effectively solving the problem of incomplete cleaning in the dead zone at the bottom of the heating stage. By controlling the amount of oxygen introduced through the second gas path to be 5% to 15% of the total gas introduced through the first and second gas paths, the oxygen at the bottom and the fluorine-containing free radical gas entering from the top can form a complementary convection flow, suppressing the recombination loss of fluorine free radicals during transport and improving cleaning efficiency. Furthermore, the oxygen can oxidize carbon-based organic byproducts into carbon dioxide and water vapor, thus comprehensively removing deposits from both inorganic and organic surfaces of the chamber walls. This precise ratio avoids dilution or side reactions caused by excessive oxygen, eliminating the need to excessively extend the cleaning time or increase the gas flow rate. Therefore, this cleaning system can improve the cleanliness of chemical vapor deposition equipment. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments disclosed in this specification, the drawings used in the description of the embodiments disclosed in this specification or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a cleaning system for a chemical vapor deposition apparatus according to an embodiment of this disclosure; Figure 2 This is a schematic flowchart of a cleaning method for a chemical vapor deposition apparatus according to an embodiment of this disclosure. Detailed Implementation

[0019] The technical solutions described herein will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of this disclosure and are used to illustrate the concept of this disclosure. These descriptions are illustrative and exemplary and should not be construed as limiting the implementation methods or the scope of protection of this disclosure. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein.

[0020] It should be noted that the accompanying drawings in this embodiment are schematic diagrams used to illustrate the concept of this disclosure, and to schematically show the shape and interrelationship of each part. It should be understood that, in order to clearly show the structure of each component of this disclosure, the drawings are not drawn to the same scale, and the same reference numerals are used to indicate the same parts in the drawings.

[0021] As described in the background section, chemical vapor deposition (CVD) is one of the core technologies for preparing dielectric thin films in semiconductor manufacturing processes. Among them, sub-atmospheric chemical vapor deposition (SACVD) is widely used in key processes such as shallow trench isolation filling and interlayer dielectric layer deposition due to its excellent trench filling capability and film quality.

[0022] However, in chemical vapor deposition (CVD) equipment, byproducts (such as unreacted precursors and reactive polymers) tend to accumulate in "dead zones" where airflow is difficult to achieve sufficient circulation, such as the edges of the spray nozzles, the bottom of the heating stage, and the transport channels within the reaction chamber. These residues not only contaminate the wafer surface and reduce product yield, but also cause process parameter drift, affecting the stability and repeatability of equipment operation.

[0023] Therefore, how to provide technical solutions to improve the cleanliness of chemical vapor deposition equipment has become an urgent technical problem to be solved.

[0024] The cleaning system and cleaning method for a chemical vapor deposition (CVD) apparatus provided in this disclosure include: a reaction chamber; an air inlet located at the top of the reaction chamber; a first gas path, the first end of which is connected to a remote plasma source located outside the reaction chamber to receive fluorine-containing free radical gas from the remote plasma source; the second end of the first gas path is connected to the air inlet to deliver fluorine-containing free radical gas into the reaction chamber; a heating stage located inside the reaction chamber; a second gas path, the first end of which is connected to an external gas holder module to receive oxygen from the external gas holder module; the second end of the second gas path is located at the bottom of the reaction chamber and below the heating stage, and is connected to the reaction chamber to deliver oxygen into the reaction chamber; the amount of oxygen introduced into the second gas path accounts for 5% to 15% of the total amount of gas introduced into the first and second gas paths. By decoupling the second gas path to an external gas holder module and positioning its inlet at the bottom of the reaction chamber below the heating stage, precise directional oxygen delivery can be achieved, effectively solving the problem of incomplete cleaning in the dead zone at the bottom of the heating stage. By controlling the amount of oxygen introduced through the second gas path to be 5% to 15% of the total gas introduced through the first and second gas paths, the oxygen at the bottom and the fluorine-containing free radical gas entering from the top can form a complementary convection flow, suppressing the recombination loss of fluorine free radicals during transport and improving cleaning efficiency. Furthermore, the oxygen can oxidize carbon-based organic byproducts into carbon dioxide and water vapor, thus comprehensively removing deposits from both inorganic and organic surfaces of the chamber walls. This precise ratio avoids dilution or side reactions caused by excessive oxygen, eliminating the need to excessively extend the cleaning time or increase the gas flow rate. Therefore, this cleaning system can improve the cleanliness of chemical vapor deposition equipment.

[0025] To make the above-described objects, features and advantages of this disclosure more apparent and understandable, the disclosure is illustrated below with reference to the accompanying drawings.

[0026] See Figure 1 , Figure 1 This is a schematic diagram of a cleaning system for a chemical vapor deposition apparatus according to an embodiment of this disclosure.

[0027] like Figure 1 As shown, in this embodiment, the cleaning system of the chemical vapor deposition equipment includes a reaction chamber 100.

[0028] The reaction chamber 100 provides a sealed reaction space for the chemical vapor deposition process.

[0029] In this embodiment, the reaction chamber 100 is the reaction chamber of a sub-atmospheric chemical vapor deposition (SACVD) device.

[0030] During the cleaning process, cleaning gas or active material flows within the reaction chamber 100 and reacts with byproducts adhering to the inner wall of the chamber and the surface of components to remove them.

[0031] In some embodiments, the reaction chamber 100 may also be the reaction chamber of other types of chemical vapor deposition equipment, such as a low-pressure chemical vapor deposition (LPCVD) device, a plasma-enhanced chemical vapor deposition (PECVD) device, or a metal-organic chemical vapor deposition (MOCVD) device. This disclosure does not impose specific limitations on this.

[0032] An air inlet 110 is provided at the top of the reaction chamber 100.

[0033] The air inlet 110 is connected to the internal space of the reaction chamber 100, serving as a channel for gas to enter the reaction chamber 100.

[0034] In some embodiments, the air inlet 110 is a showerhead located at the top of the reaction chamber 100. Gas diffuses into the reaction chamber 100 through a plurality of evenly distributed air outlets at the bottom of the showerhead, thereby improving the uniformity of gas distribution after entering the reaction chamber 100.

[0035] Specifically, during the cleaning process, active substances such as fluorine-containing free radical gases enter the reaction chamber 100 through the air inlet 110 and diffuse to the inner wall of the chamber and the surface of each component, reacting with the attached byproducts to remove them.

[0036] A heating platform 120 is also provided inside the reaction chamber 100.

[0037] The heating stage 120 is used to hold the wafer and heat the wafer during the deposition process to provide the temperature conditions required for the chemical reaction.

[0038] In this embodiment, the heating stage 120 is disposed in the bottom region of the reaction chamber 100, and has a horizontal wafer support surface for placing the semiconductor wafer to be processed.

[0039] The heating platform 120 can be raised and lowered vertically.

[0040] Specifically, the bottom of the heating platform 120 is connected to a lifting mechanism (not shown in the figure), such as a screw lifting mechanism, a cylinder lifting mechanism, or a lifting assembly driven by a stepper motor. The lifting mechanism drives the heating platform 120 to reciprocate in the vertical direction to adjust the distance between the support surface of the heating platform 120 and the top of the reaction chamber 100 (e.g., a spray head or air inlet 110). The adjustment of the distance can change the airflow field distribution and airflow path inside the reaction chamber 100, thereby affecting the diffusion behavior and distribution uniformity of the reaction gas or cleaning gas in the chamber.

[0041] In some embodiments, during the cleaning process, the heating platform 120 can also change the diffusion range and distribution pattern of the cleaning gas inside the reaction chamber 100 by lifting and lowering in conjunction with the delivery of cleaning gas, so that the cleaning gas is mixed and distributed more evenly, thereby further improving the cleaning effect.

[0042] The cleaning system also includes a first air passage 131.

[0043] The first air passage 131 has a first end 131a and a second end 131b.

[0044] Specifically, the first end 131a is connected to a remote plasma source 140 located outside the reaction chamber 100, and the second end 131b is connected to the gas inlet 110. The first gas passage 131 is used to transport fluorine-containing free radical gas from the remote plasma source 140 to the interior of the reaction chamber 100. In other words, the first end 131a of the first gas passage 131 is connected to the remote plasma source 140 located outside the reaction chamber 100 to receive fluorine-containing free radical gas from the remote plasma source; the second end 131b of the first gas passage 131 is connected to the gas inlet 110 located at the top of the reaction chamber 100 to deliver the fluorine-containing free radical gas into the reaction chamber.

[0045] The remote plasma source 140 is used to receive initial gas from the external gas holder module 150 and to dissociate the initial gas to generate highly active fluorine-containing free radical gas.

[0046] Specifically, the remote plasma source 140 is equipped with a plasma generation chamber, in which the initial gas is excited by radio frequency energy or microwave energy to form a plasma containing a large number of free radical active substances. Since the plasma is generated outside the reaction chamber 100, physical bombardment damage to the internal components and wafers of the reaction chamber 100 by high-energy ions is avoided.

[0047] The initial gas is a fluorine-containing gas. For example, the initial gas can be one or more of nitrogen trifluoride and oxygen.

[0048] In some embodiments, the initial gas is nitrogen trifluoride gas. The nitrogen trifluoride is dissociated in a remote plasma source 140 to generate fluorine radicals, which are the main active substances for removing silicon-containing deposits (such as silica) adhering to the inner wall of the reaction chamber 100.

[0049] In some embodiments, the initial gas is a mixture of nitrogen trifluoride and oxygen. Nitrogen trifluoride is dissociated in the remote plasma source 140 to generate fluorine radicals, which are the main active substances for removing silicon-containing deposits (such as silica) adhering to the inner wall of the reaction chamber 100. Oxygen is dissociated in the remote plasma source 140 to generate oxygen radicals, which are used to oxidize organic polymer byproducts adhering to the inner wall of the chamber into volatile gases such as carbon dioxide and water.

[0050] It should be noted that the gas processed by the remote plasma source 140 contains not only highly reactive fluorine and oxygen radicals, but may also contain incompletely dissociated initial gas molecules and byproducts generated after radical recombination (such as F2, NF). x (etc.). The fluorine-containing free radical gas is transported to the reaction chamber 100 via the first gas path 131 and participates in the subsequent cleaning reaction.

[0051] The cleaning system also includes a second air passage 132.

[0052] The second air passage 132 has a first end 132a and a second end 132b.

[0053] Specifically, the first end 132a of the second gas passage 132 is connected to the external gas holder module 150 to receive oxygen from the external gas holder module 150. The second end 132b is located at the bottom of the reaction chamber 100 and below the heating platform 120, and is connected to the internal space of the reaction chamber 100 to supply oxygen to the reaction chamber 100.

[0054] The second air passage 132 is set independently of the first air passage 131.

[0055] Specifically, the second gas path 132 does not supply gas to the reaction chamber 100 via the remote plasma source 140, but instead directly delivers oxygen from the external gas holder module 150 to the bottom of the reaction chamber 100. Therefore, oxygen can directly enter the bottom region of the reaction chamber 100 in molecular form without undergoing the dissociation treatment of the remote plasma source 140, thus avoiding oxygen loss due to recombination reactions in the transmission pipeline and ensuring that the oxygen concentration and activity reaching the bottom region of the heating stage 120 meet the requirements of the cleaning process.

[0056] The second gas path 132 delivers oxygen from the external gas holder module 150 to the bottom of the reaction chamber 100, in the area below the heating stage 120. This allows oxygen to reach the dead-angle area below the heating stage 120 directly in molecular form without passing through the remote plasma source 140. On one hand, this oxygen and the fluorine-containing free radical gas entering from the top inlet 110 and diffusing downwards form a convective complementary relationship around the heating stage 120, suppressing the recombination loss of fluorine free radicals and increasing the effective fluorine free radical concentration. On the other hand, the oxygen itself acts as an oxidant, oxidizing the organic polymer byproducts attached to this area into volatile gases such as CO2 and H2O, which are then removed by the vacuum system. This achieves directional, uniform, and thorough cleaning of traditional cleaning dead-angle areas, effectively avoiding particulate contamination caused by the shedding of residues from dead-angle areas, thereby comprehensively improving the cleanliness and process yield of the chemical vapor deposition equipment.

[0057] In this embodiment, the amount of oxygen introduced into the second gas passage 132 is between 5% and 15% of the total amount of gas (fluorine-containing free radical gas) introduced into the first gas passage 131 and the oxygen introduced into the second gas passage 132. This ratio range ensures sufficient oxygen to participate in the synergistic reaction at the bottom of the heating platform 120, while avoiding excessive dilution of the fluorine-containing free radical gas due to excessive oxygen, and also inhibits fluorine free radical recombination, thereby improving cleaning efficiency and maintaining reaction uniformity.

[0058] See also Figure 1 In this embodiment, the second end 132b of the second gas passage 132 is provided with a plurality of air outlets (not shown in the figure). These outlets are located at the bottom of the reaction chamber 100 and are evenly distributed circumferentially along the heating platform 120. The outlets are positioned towards the bottom region of the heating platform 120 to uniformly spray oxygen into the space below the heating platform 120. Through this uniformly distributed porous structure, the oxygen introduced through the second gas passage 132 can form a uniform airflow field at the bottom of the heating platform 120, avoiding uneven cleaning caused by excessively high or low local oxygen concentrations.

[0059] In this embodiment of the present disclosure, the heating platform 120 can be raised and lowered in the vertical direction.

[0060] In the second gas path 132, the amount of oxygen supplied when the heating platform 120 is at a first height is less than the amount of oxygen supplied when the heating platform 120 is at a second height, wherein the first height is less than the second height. In other words, when the heating platform 120 rises to a higher position, the amount of oxygen supplied through the second gas path 132 increases accordingly.

[0061] Understandably, as the heating platform 120 rises, the space between the bottom of the heating platform 120 and the bottom of the reaction chamber 100 increases, increasing the filling volume required for oxygen diffusion in this area. After the heating platform 120 rises, the distance between the top air inlet 110 and the upper surface of the heating platform 120 decreases, compressing the flow path of the fluorine-containing free radical gas at the top of the chamber, requiring more active material to diffuse towards the periphery and bottom of the heating platform 120. Increasing the oxygen flow rate through the second gas path 132 at this time helps maintain the convective complementary balance between the oxygen at the bottom and the fluorine-containing free radical gas at the top, ensuring that the bottom area of ​​the heating platform 120 receives sufficient oxygen to participate in the cleaning reaction regardless of the height of the heating platform 120.

[0062] The remote plasma source 140 dissociates fluorine-containing gas (such as NF3) to generate fluorine-containing free radical gas, which enters the interior of the reaction chamber 100 from the top through the first gas path 131 and the inlet 110, and diffuses from top to bottom. The external gas holder module 150 introduces oxygen into the area below the heating platform 120 at the bottom of the reaction chamber 100 through the second gas path 132, and the oxygen diffuses from bottom to top. The two form a complementary convection current in the area around the heating platform 120.

[0063] When the oxygen comes into contact with fluorine radicals, it can suppress the efficiency decay of fluorine radicals due to recombination during long-distance transport, thereby increasing the effective concentration of fluorine radicals reaching the bottom area of ​​the heating stage 120.

[0064] It should be noted that the ratio of oxygen to fluorine-containing gas (NF3) needs to be strictly limited. The proportion of oxygen in the total gas volume should not exceed 50%. If this range is exceeded, oxygen will not only fail to inhibit fluorine radical recombination but will also reduce the fluorine radical content. In this embodiment, a small amount of oxygen is used, preferably the amount of oxygen introduced into the second gas passage 132 is 5% to 15% of the total amount of the gas (fluorine radical-containing gas) introduced into the first gas passage 131 and the oxygen introduced into the second gas passage 132.

[0065] The oxygen itself acts as an oxidant, which can oxidize the organic polymer byproducts attached to the inner wall of the chamber and the surface of the heating stage 120 into volatile gases such as carbon dioxide and water, which are then removed by the vacuum system, thereby further improving the cleaning effect from the perspective of organic matter removal.

[0066] This embodiment of the present disclosure achieves directional, uniform, and sufficient oxygen supply to the bottom area of ​​the heating stage 120 by independently setting the second gas path 132 below the heating stage 120 at the bottom of the reaction chamber 100, and by cooperating with precise oxygen flow control (accounting for 5% to 15% of the total), oxygen quantity adjustment linked to the lifting of the heating stage 120, and gas outlet structure evenly distributed along the circumference of the heating stage 120, thereby improving the overall cleanliness of the chemical vapor deposition equipment.

[0067] The cleaning system also includes a third air passage 133.

[0068] The third air passage 133 has a first end 133a and a second end 133b.

[0069] Specifically, the first end 133a is connected to the external gas holder module 150 to receive nitrogen trifluoride (NF3) from the external gas holder module 150. The second end 133b is connected to the remote plasma source 140 to supply the nitrogen trifluoride to the remote plasma source 140.

[0070] The third gas path 133 is provided independently of the first gas path 131 and the second gas path 132. The third gas path 133 serves as a supply path for fluorine-containing gas and is specifically used to transport nitrogen trifluoride from the external gas holder module 150 to the remote plasma source 140.

[0071] Upon receiving nitrogen trifluoride supplied via the third gas path 133, the remote plasma source 140 dissociates it using radio frequency or microwave energy, generating highly reactive fluorine radicals and other fluorine-containing active substances. These are then transported via the first gas path 131 to the reaction chamber 100 to participate in the cleaning reaction. Through the coordination of the third gas path 133 and the first gas path 131, a complete gas path chain is achieved, encompassing fluorine gas supply (third gas path 133), active substance generation (remote plasma source 140), and active substance delivery (first gas path 131). By separating the raw material supply path from the product delivery path, independent flow control and process optimization can be performed on each path, improving the flexibility of system control and the stability of the cleaning process.

[0072] In some embodiments, the third gas path 133 may also be equipped with a mass flow controller (MFC) and a switching valve (not shown) for precisely controlling the flow rate and on / off state of nitrogen trifluoride introduced into the remote plasma source 140, thereby adjusting the yield of fluorine radicals in real time according to the cleaning process requirements.

[0073] In some embodiments, the remote plasma source 140, in addition to receiving nitrogen trifluoride delivered via the third gas path 133, may also receive other fluorine-containing gases or auxiliary gases (e.g., oxygen, argon, etc. delivered via other gas paths) to generate fluorine-containing gases or mixed free radical gases. Exemplarily, the remote plasma source 140 may simultaneously receive nitrogen trifluoride and oxygen to generate a mixed reactive substance of fluorine and oxygen free radicals, thereby achieving synergistic removal of silicon-containing deposits and organic byproducts.

[0074] In some embodiments, the cleaning system further includes a fourth air passage 134.

[0075] The fourth air passage 134 has a first end 134a and a second end 134b.

[0076] Specifically, the first end 134a is connected to the external gas holder module 150 to receive oxygen from the external gas holder module 150. The second end 134b is connected to the remote plasma source 140 to supply the oxygen to the remote plasma source 140.

[0077] The fourth gas path 134 is independently configured from the second gas path 132. The fourth gas path 134 serves as another oxygen supply path, specifically for delivering oxygen from the external gas holder module 150 to the remote plasma source 140. Upon receiving nitrogen trifluoride delivered via the third gas path 133 and oxygen delivered via the fourth gas path 134, the remote plasma source 140 dissociates both using radio frequency or microwave energy, generating a mixed reactive gas containing fluorine and oxygen free radicals. This gas is then delivered to the reaction chamber 100 via the first gas path 131. By simultaneously dissociating oxygen and nitrogen trifluoride at the remote plasma source 140, fluorine and oxygen free radicals can be generated, achieving synergistic removal of silicon-containing deposits (etched into SiF4 gas by fluorine free radicals) and organic byproducts (oxidized into carbon dioxide and water gas by oxygen free radicals). Furthermore, oxygen free radicals can inhibit fluorine free radical recombination, thereby improving cleaning efficiency.

[0078] In some embodiments, the total amount of oxygen input through the fourth gas path 134 and oxygen introduced through the second gas path 132 accounts for 5% to 20% of the total amount of gas introduced into the reaction chamber 100 through the first gas path 131 and the second gas path 132. In other words, the sum of the oxygen that finally reaches the reaction chamber 100 after entering the remote plasma source 140 via the fourth gas path 134 and the oxygen that is directly delivered to the bottom of the reaction chamber 100 via the second gas path 132 accounts for 5% to 20% of the total amount of fluorine-containing free radical gas introduced through the first gas path 131 and oxygen from both gas paths. This range ensures a sufficient supply of both oxygen free radicals and molecular oxygen in the chamber, while avoiding excessive dilution of fluorine free radicals due to excessive total oxygen content, as well as the consumption of fluorine free radicals by side reactions, thereby achieving a synergistic balance between inorganic etching and organic removal.

[0079] In some embodiments, the amount of oxygen input through the fourth gas path 134 is greater than the amount of oxygen input through the second gas path 132. In other words, most of the oxygen enters the reaction chamber 100 as oxygen free radicals after being dissociated by the remote plasma source 140, for the oxidation and removal of organic byproducts; while a smaller portion of the oxygen is directly transported in molecular form to the bottom region of the heating stage 120 via the second gas path 132, for the oxidation of organic residues in the bottom dead corner region. This ensures both efficient removal of organic matter in the main region of the chamber and specialized cleaning of the bottom dead corner, achieving an optimized configuration of oxygen supply.

[0080] In some embodiments, both the fourth gas path 134 and the second gas path 132 are connected to the external gas holder module 150. In other words, whether the oxygen is input from the remote plasma source 140 via the fourth gas path 134 or the oxygen is directly delivered to the bottom of the reaction chamber 100 via the second gas path 132, it all originates from the same external gas holder module 150 and is uniformly allocated and managed by the external gas holder module 150.

[0081] In some embodiments, the external gas holder module 150 is used to provide various gases and control gas flow and on / off.

[0082] Specifically, the external gas holder module 150 integrates multiple mass flow controllers (MFCs), pneumatic valves, manual valves, pressure sensors, and gas filters, which are used to accurately measure and control the gas flow into each gas path (second gas path 132, third gas path 133, and fourth gas path 134) and switch the on / off of each gas path according to the process sequence.

[0083] In this embodiment, the external gas holder module 150 can control the input flow rate of nitrogen trifluoride in the third gas path 133, the oxygen flow rate input to the remote plasma source 140 in the fourth gas path 134, and the oxygen flow rate directly input to the bottom of the reaction chamber 100 in the second gas path 132 through its internally integrated flow control element. Through the centralized control of the external gas holder module 150, precise regulation of the type, flow rate ratio, and timing of each gas in the cleaning process can be achieved.

[0084] Accordingly, this disclosure also provides a method for cleaning a chemical vapor deposition apparatus.

[0085] The cleaning method for the chemical vapor deposition equipment can be applied to the cleaning system described in any of the above embodiments.

[0086] See Figure 2 , Figure 2 This is a schematic flowchart of a cleaning method for a chemical vapor deposition apparatus according to an embodiment of this disclosure. The method can be performed by executing the following steps S201 to S203.

[0087] Step S201: Dissociate the fluorine-containing gas using a remote plasma source to generate fluorine-containing free radical gas.

[0088] Step S202: The fluorine-containing free radical gas is delivered to the top of the reaction chamber through the first gas path and the gas inlet.

[0089] Step S203: Oxygen is introduced into the area below the heating platform at the bottom of the reaction chamber through the second gas path, and the amount of oxygen introduced accounts for 5% to 15% of the total amount of gas introduced through the first and second gas paths.

[0090] Understandably, cleaning methods for chemical vapor deposition equipment may include more or fewer steps, and the order of the steps may be the same or different.

[0091] See below for reference. Figure 1 and Figure 2 The above methods will be explained.

[0092] In step S201, the fluorine-containing gas is dissociated by a remote plasma source to generate fluorine-containing free radical gas.

[0093] Specifically, the remote plasma source 140 receives fluorine-containing gas from the external gas holder module 150.

[0094] In some embodiments, the fluorine-containing gas is nitrogen trifluoride (NF3). The remote plasma source excites the nitrogen trifluoride with radio frequency energy or microwave energy, causing it to undergo a dissociation reaction, generating highly reactive fluorine free radicals and other fluorine-containing active substances. The fluorine free radicals generated by the dissociation reaction are the main active substances for removing silicon-containing deposits (such as silicon dioxide SiO2) adhering to the inner wall of the reaction chamber.

[0095] In some embodiments, the fluorine-containing gas may also be a mixture of nitrogen trifluoride and oxygen. The remote plasma source simultaneously receives nitrogen trifluoride and oxygen, and dissociates them separately to generate a mixed reactive gas of fluorine free radicals and oxygen free radicals. The oxygen free radicals are used to oxidize organic polymer byproducts adhering to the inner wall of the reaction chamber into volatile gases such as carbon dioxide and water. Furthermore, the recombination of fluorine free radicals to generate fluorine gas can be suppressed, improving cleaning efficiency.

[0096] In some embodiments, the excitation power, gas flow rate, and working pressure of the remote plasma source can be adjusted according to actual cleaning requirements to control the yield of fluorine-containing free radical gas and the composition ratio of active substances.

[0097] It should be noted that the remote plasma source is located outside the reaction chamber. Fluorine-containing gas is dissociated within the plasma generating chamber, which is far from the reaction chamber, producing fluorine-containing free radical gas.

[0098] In step S202, the fluorine-containing free radical gas is delivered to the top of the reaction chamber via the first gas path and the gas inlet.

[0099] Specifically, the fluorine-containing free radical gas generated by the remote plasma source is transported to the reaction chamber via a first gas path. The second end of the first gas path is connected to an inlet located at the top of the reaction chamber, through which the fluorine-containing free radical gas enters the interior of the reaction chamber.

[0100] In some embodiments, the air inlet is a showerhead located at the top of the reaction chamber. The fluorine-containing free radical gas diffuses into the reaction chamber through multiple evenly distributed air outlets at the bottom of the showerhead. Through the gas distribution effect of the showerhead, the fluorine-containing free radical gas can enter the reaction chamber in a relatively uniform flow pattern and diffuse from top to bottom within the chamber. This facilitates the uniform distribution of active species across the entire cross-section of the reaction chamber, reducing the problem of incomplete local cleaning caused by uneven airflow.

[0101] The fluorine-containing free radical gas enters from the top of the reaction chamber and diffuses towards the bottom under the drive of a pressure gradient. During diffusion, the fluorine free radicals in the gas react chemically with silicon-containing deposits (such as silicon dioxide, SiO2) adhering to the inner wall of the reaction chamber, the top and side walls of the heating platform, and the bottom surface of the spray head, generating volatile gases (such as SiF4) which are then removed by the vacuum system. Oxygen free radicals (when the fluorine-containing gas contains oxygen) react with organic polymer byproducts adhering to the aforementioned areas, generating volatile gases such as carbon dioxide and water, which are also removed by the vacuum system.

[0102] In step S203, oxygen is introduced into the area below the heating platform at the bottom of the reaction chamber through the second gas path, and the amount of oxygen introduced accounts for five percent to fifteen percent of the total amount of gas introduced through the first and second gas paths.

[0103] Specifically, the second gas path is independent of the first gas path. The first end of the second gas path is connected to an external gas holder module, receiving oxygen from it; the second end of the second gas path is located at the bottom of the reaction chamber and below the heating platform, communicating with the reaction chamber. Oxygen is directly delivered via the second gas path to the area at the bottom of the reaction chamber, below the heating platform, without passing through a remote plasma source.

[0104] In some embodiments, a plurality of air outlets are provided at the second end of the second gas path. The plurality of air outlets are located at the bottom of the reaction chamber and are evenly distributed along the circumference of the heating platform. Oxygen is evenly sprayed into the space below the heating platform through the plurality of air outlets, forming a uniform airflow field at the bottom of the heating platform, thereby avoiding uneven cleaning caused by uneven local oxygen concentration.

[0105] In some embodiments, the introduction of oxygen into the second gas path and the introduction of fluorine-containing free radical gas into the first gas path can be carried out simultaneously.

[0106] Specifically, fluorine-containing free radical gas enters from the top of the reaction chamber and diffuses downwards, while oxygen enters from below the heating platform at the bottom of the reaction chamber and diffuses upwards. The two gases then form complementary convection currents around the heating platform. On one hand, the contact between oxygen and fluorine free radicals inhibits the recombination and loss of fluorine free radicals, increasing the effective concentration of fluorine free radicals within the reaction chamber. On the other hand, oxygen itself acts as an oxidant, oxidizing organic polymer byproducts adhering to the bottom and surrounding areas of the heating platform into volatile gases such as carbon dioxide and water, which are then removed by the vacuum system, thus achieving comprehensive cleaning of this traditionally neglected cleaning area.

[0107] In some embodiments, the duration of oxygen introduction in the second gas path is less than or equal to the duration of introduction of the fluorine-containing free radical gas. In other words, oxygen can be introduced into the second gas path after the remote plasma source has been started and the fluorine-containing free radical gas has been stably generated, and / or the oxygen introduction into the second gas path can be stopped before the fluorine-containing free radical gas is stopped. Through the above timing control, the waste of oxygen and the risk of excessive oxidation of the chamber caused by continuously introducing oxygen before the plasma has been stably established or the cleaning reaction has been basically completed can be avoided, which is conducive to optimizing gas consumption and process efficiency while ensuring the cleaning effect. In addition, introducing fluorine-containing free radical gas first to establish the plasma cleaning environment, and then introducing bottom oxygen at the appropriate time, also helps to avoid the premature entry of oxygen into the chamber, which would adversely affect the cleaning efficiency of fluorine free radicals.

[0108] In some embodiments, before the fluorine-containing gas is dissociated by the remote plasma source, nitrogen trifluoride gas is introduced into the remote plasma source through a third gas path, and oxygen is introduced into the remote plasma source through a fourth gas path.

[0109] Specifically, the cleaning system further includes an external gas holder module, a third gas path, and a fourth gas path. The external gas holder module is used to provide various gases and control gas flow and on / off. The third gas path connects the external gas holder module and the remote plasma source, and is used to transport nitrogen trifluoride from the external gas holder module to the remote plasma source. The fourth gas path connects the external gas holder module and the remote plasma source, and is used to transport oxygen from the external gas holder module to the remote plasma source. The nitrogen trifluoride gas input through the third gas path and the oxygen gas input through the fourth gas path are mixed in the remote plasma source and jointly dissociated under the excitation of the remote plasma source, generating a mixed reactive species gas containing fluorine radicals and oxygen radicals.

[0110] Specifically, the total amount of oxygen input through the fourth gas path and oxygen introduced through the second gas path accounts for 5% to 20% of the total amount of gas introduced into the reaction chamber through the first and second gas paths. In other words, the sum of oxygen entering the remote plasma source via the fourth gas path and then entering the reaction chamber through the first gas path, and oxygen directly entering the bottom of the reaction chamber through the second gas path, accounts for 5% to 20% of the total amount of fluorine-containing free radical gas introduced through the first gas path and oxygen from both gas paths.

[0111] In some embodiments, the amount of oxygen input through the fourth gas path is greater than the amount of oxygen input through the second gas path. That is, most of the oxygen is dissociated into oxygen free radicals by the remote plasma source and enters the main area of ​​the reaction chamber for the oxidation and removal of organic by-products. A smaller portion of the oxygen is directly transported to the bottom of the heating stage in molecular form through the second gas path to suppress the recombination loss of fluorine free radicals and to oxidize the organic residues in the dead corner area at the bottom.

[0112] In step S203, the remote plasma source receives nitrogen trifluoride from the third gas path and oxygen from the fourth gas path, dissociating them to generate fluorine-containing free radical gas (including fluorine and oxygen free radicals). This fluorine-containing free radical gas is delivered to the top of the reaction chamber via the first gas path and the inlet, while oxygen is introduced into the bottom of the reaction chamber below the heating stage via the second gas path. Thus, the fluorine-containing free radical gas diffuses downwards from the top, and the oxygen diffuses upwards from the bottom, creating a complementary convection current within the reaction chamber. This ensures a sufficient supply of active species required for cleaning the main area of ​​the chamber, while the directional supply of oxygen at the bottom effectively cleans the dead corners at the bottom of the heating stage. This comprehensively removes deposits from both inorganic and organic surfaces on the inner wall of the chamber, significantly improving the overall cleanliness of the chemical vapor deposition equipment.

[0113] The foregoing describes several embodiments of cleaning systems and methods for chemical vapor deposition equipment. The various optional methods described in each embodiment can be combined and cross-referenced without conflict, thereby extending to a variety of possible embodiments. These can all be considered as embodiments disclosed in this publication.

[0114] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article indicates that the preceding and following related objects have an "or" relationship.

[0115] In the embodiments of this application, "multiple" refers to two or more.

[0116] The descriptions of "first," "second," etc., appearing in the embodiments of this application are for illustrative purposes and to distinguish the objects being described. They have no order and do not indicate any special limitation on the number of objects in the embodiments of this application. They cannot constitute any limitation on the embodiments of this application.

[0117] While the embodiments disclosed herein are as described above, this disclosure is not limited thereto. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this disclosure; therefore, the scope of protection of this disclosure should be determined by the scope defined in the claims.

Claims

1. A cleaning system for a chemical vapor deposition (CVD) apparatus, characterized in that, include: Reaction chamber; The air inlet is located at the top of the reaction chamber; A first gas path, the first end of which is connected to a remote plasma source located outside the reaction chamber to receive fluorine-containing free radical gas from the remote plasma source, the fluorine-containing free radical gas being obtained by the remote plasma source from the initial gas received from the external gas holder module and then processed; the second end of the first gas path is connected to the gas inlet to deliver the fluorine-containing free radical gas into the reaction chamber. A heating platform located within the reaction chamber; The second gas passage has a first end connected to an external gas holder module to receive oxygen from the external gas holder module. The second end of the second gas passage is located at the bottom of the reaction chamber and below the heating platform, communicating with the reaction chamber to supply oxygen to the reaction chamber; The amount of oxygen introduced into the second gas path accounts for 5% to 15% of the total amount of gas introduced into the first and second gas paths.

2. The cleaning system according to claim 1, characterized in that, Also includes: Third airway; The first end of the third gas path is connected to the external gas holder module to receive nitrogen trifluoride from the external gas holder module; The second end of the third gas path is connected to the remote plasma source to deliver the nitrogen trifluoride to the remote plasma source.

3. The cleaning system according to claim 2, characterized in that, Also includes: Fourth airway; The first end of the fourth gas passage is connected to the external gas holder module to receive oxygen from the external gas holder module; The second end of the fourth gas path is connected to the remote plasma source to deliver the oxygen to the remote plasma source; The total amount of oxygen input through the fourth gas path and oxygen introduced through the second gas path accounts for 5% to 20% of the total amount of gas introduced into the reaction chamber through the first and second gas paths.

4. The cleaning system according to claim 3, characterized in that, The amount of oxygen input through the fourth gas passage is greater than the amount of oxygen input through the second gas passage.

5. The cleaning system according to claim 3, characterized in that, Both the fourth gas passage and the second gas passage are connected to the external gas holder module; The external gas holder module is used to provide various gases and control gas flow and on / off.

6. The cleaning system according to claim 1, characterized in that, The heating platform can be raised and lowered vertically. In the second gas path, the amount of oxygen introduced when the heating platform is at the first height is less than the amount of oxygen introduced when the heating platform is at the second height; The first height is smaller than the second height.

7. The cleaning system according to claim 1, characterized in that, The second end of the second gas path is provided with multiple gas outlets, which are located at the bottom of the reaction chamber and are evenly distributed along the circumference of the heating platform.

8. A cleaning method for a chemical vapor deposition apparatus, applied to the cleaning system as described in any one of claims 1 to 7, characterized in that, include: Fluorine-containing gas is dissociated using a remote plasma source to generate fluorine-containing free radical gas; The fluorine-containing free radical gas is delivered to the top of the reaction chamber via the first gas path and the gas inlet; Oxygen is introduced into the area below the heating platform at the bottom of the reaction chamber through the second gas path, and the amount of oxygen introduced accounts for 5% to 15% of the total amount of gas introduced through the first and second gas paths.

9. The cleaning method according to claim 8, characterized in that, The duration of oxygen flow through the second gas path is less than or equal to the duration of flow of the fluorine-containing free radical gas.

10. The cleaning method according to claim 8, characterized in that, include: External gas holder module is used to supply various gases and control gas flow and on / off. And the third and fourth gas paths, which are both connected to the external gas holder module and the remote plasma source; The method includes, prior to the dissociation of the fluorine-containing gas via a remote plasma source: Nitrogen trifluoride gas is introduced into the remote plasma source through the third gas path; Oxygen is supplied to the remote plasma source through the fourth gas path; The nitrogen trifluoride gas input through the third gas path and the oxygen input through the fourth gas path are mixed in the remote plasma source; the total amount of oxygen input through the fourth gas path and oxygen introduced through the second gas path accounts for 5% to 20% of the total amount of gas introduced through the first gas path and the second gas path.

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