An ashing-cleaning method for cleaning an etching chamber and an inductively coupled plasma etching method

Abstract

The present application belongs to the technical field of semiconductor manufacturing, and particularly relates to a method for cleaning and ashing an etching chamber and an inductively coupled plasma etching method. The present application adopts a first oxygen-containing mixed gas to perform first cleaning on the etching chamber after ionization, wherein the first oxygen-containing mixed gas comprises a fluorine-based gas; adopts a second oxygen-containing mixed gas to perform second cleaning on the etching chamber after ionization; and adopts a third oxygen-containing mixed gas to perform third cleaning on the etching chamber after ionization. The present application can significantly improve the cleanliness of the chamber by performing step-by-step cleaning. The present application effectively enhances the MTBC of the etching process chamber, ensures the consistency of the etching chamber environment for etching different wafer pieces, the consistency of process parameters such as etching rate, etching thickness and etching time at each place in the wafer piece during etching, avoids abnormal etching process caused by changes in the chamber environment, affects subsequent process debugging and product stability, and significantly improves the utilization rate of the etching machine.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of semiconductor manufacturing, and particularly relates to an ashing-clean method for cleaning an etching chamber and an inductively coupled plasma etching method. BACKGROUND

[0002] In the field of semiconductor manufacturing, the etching process is a very important link. The etching process often uses an inductively coupled plasma etching (ICP) device. During the etching process, a large amount of reaction by-products, such as non-volatile by-products such as sludge, are deposited on the substrate and sidewall of the process chamber. As the number of etched wafers increases, the deposits on the inner wall of the process chamber will also accumulate, and the sludge will fall off during the etching process, resulting in poor product appearance, and even affecting the etching rate and the uniformity between and within etching chips, and the device cannot work normally. In view of the above phenomenon, normal etching operation needs to be carried out after opening the chamber for wet cleaning maintenance, but the opening chamber wet cleaning maintenance takes a long time and shortens the periodic maintenance interval time (MTBC) of the device, affecting the normal operation time of the device.

[0003] In order to reduce the frequency of opening chamber maintenance and at the same time ensure the quality of etching products, a cleaning (Clean) process is required before etching each wafer. The Clean process mainly uses argon and oxygen. Oxygen ions react with hardened sludge, and argon ions increase physical bombardment and assist plasma ignition. The basic components of sludge are organic matters such as C, H and O. Under the action of the radio frequency power source, the sludge reacts with oxygen ions to generate gas which is pumped away.

[0004] However, the traditional Clean process has poor cleaning effect, the chamber frequently falls off sludge, seriously affects the product yield, and needs to be opened for wet maintenance, resulting in frequent opening chamber maintenance. SUMMARY

[0005] The purpose of the present application is to provide an ashing-clean method for cleaning an etching chamber and an inductively coupled plasma etching method. The method provided by the present application can effectively remove etching by-products and avoid frequent sludge falling in the chamber in a short time, so that wet maintenance can be carried out after a long operation time, effectively reducing the opening chamber frequency and effectively prolonging the MTBC of the etching process chamber.

[0006] In order to achieve the above purpose, the present application provides the following technical scheme:

[0007] The present application provides an ashing-clean method for cleaning an etching chamber, comprising the following steps:

[0008] (1) the first cleaning of the etching chamber after ionization of a first oxygen-containing mixed gas, the first oxygen-containing mixed gas comprising a fluorine-based gas, the first cleaning conditions comprising: chamber pressure≥80mTorr, and the power of the upper electrode being 1000W or more higher than the power of the lower electrode;

[0009] (2) the second cleaning of the etching chamber after ionization of a second oxygen-containing mixed gas, the second cleaning conditions comprising: chamber pressure≥80mTorr, and the power of the upper electrode being 700-940W higher than the power of the lower electrode;

[0010] (3) the third cleaning of the etching chamber after ionization of a third oxygen-containing mixed gas, the third cleaning conditions comprising: chamber pressure≤50mTorr, and the power of the upper electrode being 700-940W higher than the power of the lower electrode;

[0011] Steps (1), (2) and (3) are not limited in time sequence.

[0012] Preferably, the fluorine-based gas is CF4, the first oxygen-containing mixed gas comprises an inert gas, oxygen and CF4, and the volume flow ratio of the inert gas, oxygen and CF4 is 1:(0.5-2):(0.5-2).

[0013] Preferably, the first cleaning conditions comprise: chamber pressure of 80-100mTorr, power of the upper electrode of 1000-1200W, and power of the lower electrode of 0W.

[0014] Preferably, the second oxygen-containing mixed gas comprises an inert gas and oxygen, and the volume flow ratio of the inert gas and oxygen is (1-3):(1-3).

[0015] Preferably, the second cleaning conditions comprise: chamber pressure of 80-100mTorr, power of the upper electrode of 800-1000W, and power of the lower electrode of 60-100W.

[0016] Preferably, the third oxygen-containing mixed gas comprises an inert gas and oxygen, and the volume flow ratio of the inert gas and oxygen is (1-3):(1-3).

[0017] Preferably, the third cleaning conditions comprise: chamber pressure of 20-50mTorr, power of the upper electrode of 800-1000W, and power of the lower electrode of 60-100W.

[0018] Preferably, the time of the first cleaning, the second cleaning and the third cleaning is independently 10-20min.

[0019] Preferably, steps (1), (2) and (3) are performed in sequence.

[0020] The application provides an inductively coupled plasma etching method, which comprises the following steps in sequence: formal wafer loading, etching, formal wafer unloading, die loading, cleaning, and die unloading.

[0021] The cleaning is performed by using the ashing-cleaning method in the technical solution.

[0022] The application provides a method for cleaning an etching chamber, comprising the following steps: (1) performing first cleaning on the etching chamber by ionizing a first oxygen-containing mixed gas, wherein the first oxygen-containing mixed gas comprises a fluorine-based gas, and the first cleaning is performed under the conditions that the chamber pressure is greater than or equal to 80 mTorr and the power of the upper electrode is greater than or equal to 1000 W higher than the power of the lower electrode; (2) performing second cleaning on the etching chamber by ionizing a second oxygen-containing mixed gas, wherein the second cleaning is performed under the conditions that the chamber pressure is greater than or equal to 80 mTorr and the power of the upper electrode is greater than or equal to 700 W and less than or equal to 940 W higher than the power of the lower electrode; and (3) performing third cleaning on the etching chamber by ionizing a third oxygen-containing mixed gas, wherein the third cleaning is performed under the conditions that the chamber pressure is less than or equal to 50 mTorr and the power of the upper electrode is greater than or equal to 700 W and less than or equal to 940 W higher than the power of the lower electrode; and the steps (1), (2) and (3) are not limited in time sequence. The method provided by the application can clean the etching chamber in three steps, and by controlling the chamber pressure and the power of the upper and lower electrodes, the plasma ionized in step (1) is located in the upper region of the etching chamber, and the upper substrate of the etching chamber is mainly cleaned, meanwhile, the first oxygen-containing mixed gas used in step (1) comprises a fluorine-based gas, the fluorine-based gas has strong oxidizing property and can be ionized into high-activity ion groups, and in the chemical reaction, the fluorine-based gas reacts with carbon chains to form volatile fluorocarbons, so that the carbon atoms in the residues can be quickly removed, and thus the residues on the upper substrate can be more effectively removed after being mixed with O2, and the cleaning rate can be significantly improved. The plasma ionized in step (2) is located in the middle region of the etching chamber, and the inner sidewall of the chamber is mainly cleaned; and the plasma ionized in step (3) is located in the lower region of the etching chamber, and the small gap (the small gap is prone to accumulate by-products) formed by the focusing ring, the electrostatic chuck and the connection between the electrostatic chuck and the focusing ring is mainly cleaned. The method provided by the application can clean the upper region, the middle region and the lower region of the etching chamber in steps and regions, and the first oxygen-containing mixed gas containing the fluorine-based gas is used to strengthen the cleaning of the upper substrate with serious residues, so that the cleaning effect is enhanced. Therefore, the method provided by the application can effectively remove the etching by-products, can avoid frequent residue dropping in the chamber in a short time, so that the chamber can be opened for wet maintenance after a long operation, the opening frequency of the chamber is effectively reduced, the MTBC of the etching process chamber is effectively prolonged, the environment of the etching chamber for etching different wafers is consistent, the consistency of the process parameters such as etching rate, etching thickness and etching time in the wafer during etching is ensured, the change of the chamber environment is avoided to cause abnormal etching process, the subsequent process debugging and product stability are affected, and the utilization rate of the etching machine is significantly improved.

[0023] From the results of the examples, it can be seen that by counting the number of etching pieces and the number of times of opening cavity cleaning, the etching rate of the product is monitored, and it is determined that the ashing-cleaning method provided by the application can effectively remove the etching by-products, and can be maintained by opening the cavity wetly after 100 pieces of work, thereby effectively reducing the number of times of opening the cavity. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The silicon etching rate trend chart of the Clean process in Comparative Example 1;

[0025] Figure 2 The silicon etching rate trend chart of the Ashing-Clean process in Example 2;

[0026] Figure 3 The Ashing-Clean process flow chart in the example;

[0027] Figure 4 The position schematic diagram of cleaning in step (1) of the Ashing-Clean process in Example 1;

[0028] Figure 5 The position schematic diagram of cleaning in step (2) of the Ashing-Clean process in Example 1;

[0029] Figure 6 The position schematic diagram of cleaning in step (3) of the Ashing-Clean process in Example 1;

[0030] In the figure: 1 is a mixed gas inlet, 2 is an upper radio frequency power supply, 3 is a pump, 4 is a lower radio frequency power supply, 5 is a cooling gas inlet, 6 is a three-pin, 7 is a focusing ring, 8 is an electrostatic chuck, and 9 is a plasma. DETAILED DESCRIPTION

[0031] The application provides an ashing-cleaning method for cleaning an etching chamber, comprising the following steps:

[0032] (1) a first cleaning of the etching chamber after ionization of a first oxygen-containing mixed gas, wherein the first oxygen-containing mixed gas comprises a fluorine-based gas, and the conditions of the first cleaning comprise: a cavity pressure ≥80mTorr, and a power of an upper electrode is higher than a power of a lower electrode by 1000W or more;

[0033] (2) a second cleaning of the etching chamber after ionization of a second oxygen-containing mixed gas, wherein the conditions of the second cleaning comprise: a cavity pressure ≥80mTorr, and a power of an upper electrode is higher than a power of a lower electrode by 700-940W;

[0034] (3) using a third oxygen-containing mixed gas to ionize and then to perform a third cleaning on the etching chamber, the third cleaning being performed under conditions including: chamber pressure ≤ 50 mTorr, and the power of the upper electrode being 700-940 W higher than the power of the lower electrode;

[0035] Steps (1), (2) and (3) are not limited in time sequence.

[0036] In the present application, all the raw materials / components are commercially available products well known to those skilled in the art, unless otherwise specified.

[0037] The present application uses a first oxygen-containing mixed gas to ionize and then to perform a first cleaning on the etching chamber, the first oxygen-containing mixed gas including a fluorine-based gas, the fluorine-based gas preferably being CF4, and the first cleaning being performed under conditions including: chamber pressure ≥ 80 mTorr, and the power of the upper electrode being 1000 W or more higher than the power of the lower electrode. In the present application, the first oxygen-containing mixed gas is a mixed gas containing oxygen. The first oxygen-containing mixed gas preferably includes an inert gas, oxygen and CF4. The inert gas is preferably argon. The volume flow ratio of the inert gas, oxygen and CF4 is preferably 1:(0.5-2):(0.5-2), more preferably 1:(1-2):(1-2), and in the embodiments, it can be 1:2:2. The conditions of the first cleaning preferably include: chamber pressure preferably being 80-100 mTorr, and in the embodiments, it can be 80 mTorr, 85 mTorr, 90 mTorr, 95 mTorr or 100 mTorr. The power of the upper electrode (i.e. the middle upper radio frequency power source) is preferably 1000-1200 W, and in the embodiments, it can be 1000 W, 1100 W or 1200 W. The power of the lower electrode (i.e. the middle lower radio frequency power source) is preferably 0 W. The time of the first cleaning is preferably 10-20 min, and in the embodiments, it can be 10 min, 15 min or 20 min. Figures 4-6 In the present application, during the first cleaning, the first oxygen-containing mixed gas enters the etching chamber through the mixed gas inlet 1. The present application preferably further includes: introducing a cooling gas into the etching chamber through the cooling gas inlet 5, the cooling gas being used to cool the wafer placed on the electrostatic chuck, and the cooling gas preferably being helium. Figures 4-6

[0038] ​This invention employs a second oxygen-containing mixed gas ionization to perform a second cleaning of the etching chamber. The conditions for this second cleaning include: chamber pressure ≥ 80 mToor, and the power of the upper electrode being 700–940 W higher than that of the lower electrode. In this invention, the second oxygen-containing mixed gas is a mixed gas containing oxygen. Preferably, the second oxygen-containing mixed gas includes an inert gas and oxygen. The inert gas is preferably argon. The volumetric flow rate ratio of the inert gas to oxygen is preferably (1–3):(1–3), more preferably (1–2):(1–2), and in some embodiments, it can be 1:1. The conditions for the second cleaning preferably include: a chamber pressure preferably 80–100 mToor, and in some embodiments, it can be 80 mToor, 85 mToor, 90 mToor, 95 mToor, or 100 mToor. The upper electrode (i.e....) Figures 4-6 The power of the upper-middle RF power supply is preferably 800-1000W, and in the embodiments it can be 800W, 850W, 900W, 950W or 1000W. The lower electrode (i.e. Figures 4-6 The power of the low-frequency power supply is preferably 60-100W, and in the embodiments it can be 60W, 70W, 80W, 90W or 100W. The second cleaning time is preferably 10-20 minutes, and in the embodiments it can be 10 minutes, 15 minutes or 20 minutes. In this invention, during the second cleaning, the second oxygen-containing mixed gas enters the etching chamber through the mixed gas inlet 1. During the second cleaning process, this invention preferably further includes: introducing cooling gas into the etching chamber through the cooling gas inlet 5, the cooling gas being used to cool the bare die placed on the electrostatic chuck, and the cooling gas is preferably helium.

[0039] This invention employs a third oxygen-containing mixed gas ionization for a third cleaning of the etching chamber. The conditions for this third cleaning include: chamber pressure ≤ 80 mToor, and the power of the upper electrode being 700–940 W higher than that of the lower electrode. In this invention, the third oxygen-containing mixed gas is a mixture containing oxygen. Preferably, the third oxygen-containing mixed gas includes an inert gas and oxygen. The inert gas is preferably argon. The preferred volumetric flow rate ratio of the inert gas to oxygen is (1–3):(1–3), more preferably (1–2):(1–2), and in some embodiments, it can be 1:1. The conditions for this third cleaning preferably include: a chamber pressure of 20–50 mToor, and in some embodiments, 20 mToor, 30 mToor, 40 mToor, 45 mToor, or 50 mToor. The upper electrode (i.e....) Figures 4-6 The power of the upper-middle RF power supply is preferably 800-1000W, and in the embodiments it can be 800W, 850W, 900W, 950W or 1000W. The lower electrode (i.e. Figures 4-6The power of the third cleaning is preferably 60-100W, and in the embodiments, can be 60W, 70W, 80W, 90W or 100W. The time of the third cleaning is preferably 10-20min, and in the embodiments, can be 10min, 15min or 20min. In the present application, during the third cleaning, the third oxygen-containing mixed gas enters the etching chamber through the mixed gas inlet 1. During the third cleaning, the present application preferably further comprises: introducing a cooling gas into the etching chamber through the cooling gas inlet 5, the cooling gas is used to cool the wafer placed on the electrostatic chuck, and the cooling gas is preferably helium. The present application does not have special requirements for the volume flow rate of the cooling gas, as long as the wafer can be effectively cooled during the first cleaning, the second cleaning and the third cleaning.

[0040] The present application does not have a time sequence limitation for the first cleaning, the second cleaning and the third cleaning, and in the embodiments of the present application, the first cleaning, the second cleaning and the third cleaning are sequentially performed.

[0041] The present application can significantly improve the chamber cleanliness by changing the upper and lower electrode power and the cavity pressure to step-by-step clean different parts of the etching chamber. The MTBC of the etching process chamber is effectively enhanced, the environment of the etching chamber for etching different wafers is ensured to be consistent, the consistency of the process parameters such as etching rate, etching thickness and etching time at each place in the wafer during etching is ensured, and the abnormal situation of the etching process caused by the change of the cavity environment is avoided, thereby affecting the subsequent process debugging and product stability.

[0042] The present application provides an inductively coupled plasma etching method, comprising sequentially performing: formal wafer loading, etching, formal wafer unloading, wafer loading, cleaning, wafer unloading.

[0043] The cleaning is performed by using the ashing-cleaning method in the technical solution.

[0044] In the present application, the formal wafer is a wafer coated with photoresist on the surface. The wafer is a wafer without photoresist coating on the surface. The wafer is used to protect the electrostatic chuck during the cleaning process.

[0045] In the present application, the inductively coupled plasma etching is a continuous operation, and the continuous operation comprises sequentially performing etching unit operations, and the etching unit operations comprise sequentially performing: formal wafer loading, etching, formal wafer unloading, wafer loading, cleaning, wafer unloading. The cleaning is performed by using the ashing-cleaning method in the technical solution.

[0046] In order to further illustrate the present application, the technical solutions provided by the present application are described in detail below in combination with embodiments, but they should not be understood as limiting the scope of protection of the present application.

[0047] In the following embodiments, according to Figure 3 The ashing-cleaning method flowchart is described above.

[0048] Example 1

[0049] This embodiment provides an ashing-cleaning method for cleaning an etching chamber, including the following steps:

[0050] (1) Set the cavity pressure to 80 mToor, adjust the upper electrode power (SrcRFPower, SRF) to 1000 W, the lower electrode power (BiasRFPower, BRF) to 0 W, and the volumetric flow rate ratio of Ar, O2, and CF4 to 1:2:2, specifically 100 sccm, 200 sccm, and 200 sccm respectively, where O2, Ar, and CF4 are supplied by... Figure 4 The mixed gas is introduced through inlet 1. The cleaning time is 20 minutes. During the cleaning process, CF4 ionizes into highly reactive ion clusters, and the plasma generated by ionization is located in the upper region of the chamber (e.g., Figure 4 The plasma (9) in the chamber mainly consists of O2 and CF4 mixed and ionized, which reacts chemically with the organic matter in the glue residue to remove the glue residue. This step mainly cleans the upper substrate of the chamber.

[0051] (2) Set the cavity pressure to 85 mToor, adjust the upper electrode power (SrcRFPower, SRF) to 800 W, the lower electrode power (BiasRFPower, BRF) to 60 W, and the volumetric flow rate ratio of Ar to O2 to be 1:1, specifically 200 sccm and 200 sccm respectively, where O2 and Ar are supplied by... Figure 5 The mixed gas is introduced through inlet 1. The cleaning time is 20 minutes. During the cleaning process, the plasma generated by ionization is located in the middle region of the chamber (e.g., Figure 5 In the plasma (9), this step mainly involves cleaning the side walls of the chamber.

[0052] (3) Set the cavity pressure to 20 mToor, adjust the upper electrode power (SrcRFPower, SRF) to 800 W, the lower electrode power (BiasRFPower, BRF) to 60 W, and the volumetric flow rate ratio of Ar to O2 to be 1:1, specifically 200 sccm and 200 sccm respectively, where O2 and Ar are supplied by... Figure 6 The mixed gas is introduced through inlet 1. The cleaning time is 20 minutes. During the cleaning process, the plasma generated by ionization is located in the lower region of the chamber (e.g., Figure 6 In the plasma (9), this step mainly involves cleaning the lower sidewall of the cavity, the focusing ring, and the Chuck platform.

[0053] Example 2

[0054] The embodiment provides an inductively coupled plasma etching method, which comprises the following steps in sequence: formal wafer loading, etching, formal wafer unloading, die loading, cleaning, and die unloading; wherein the cleaning is performed by using the ashing-cleaning method provided in the embodiment 1.

[0055] Test Example 1

[0056] For 100 wafers continuously operated in the embodiment 2, one wafer is taken every 10 wafers for monitoring, nine points of each wafer are measured by using an optical thickness meter before and after etching, and the average etching rate is calculated, and the etching rate trend chart is as shown in Figure 2 After etching the 100th wafer, the etching rate is reduced, and the reason is that some etching by-products in the etching cavity are not completely removed, part of the plasma is consumed, and the etching rate of the bottom wafer is reduced.

[0057] Comparative Example 1

[0058] The comparative example provides an inductively coupled plasma etching method, which comprises the following steps in sequence: formal wafer loading, etching, formal wafer unloading, die loading, cleaning, and die unloading; wherein the cleaning is performed by using a conventional Clean cleaning method.

[0059] The conventional Clean cleaning method comprises the following steps:

[0060] The cavity pressure is set to 80 mToor, the upper electrode power (SrcRFPower) is adjusted to 800 W, the lower electrode power (BiasRFPower) is adjusted to 60 W, the volume flow rate ratio of Ar and O2 is 1:1, and the specific values are 200 sccm and 200 sccm respectively, wherein the O2 and Ar are introduced by the mixed gas inlet 1 in the Figure 5 The cleaning time is 20 min.

[0061] Test Example 2

[0062] For 40 wafers continuously operated in the comparative example 1, one wafer is taken every 5 wafers for rate monitoring, nine points of each wafer are measured by using an optical thickness meter before and after etching, and the average etching rate is calculated, and the Clean process etching rate trend chart is as shown in Figure 1 As shown in Figure 1 As shown in The traditional Clean process in the comparative example 1 reduces the etching rate to 0.624 μm / min after 30 wafers are continuously operated, the cavity frequently drops slag, seriously affects the product yield, needs to be opened for wet maintenance, and leads to frequent opening of the cavity for maintenance.

[0063] From the above examples and comparative examples, it can be seen that the ashing-cleaning method for cleaning the etching chamber provided by the application can effectively remove the etching by-products by changing the cleaning gas and the chamber pressure to clean the etching process chamber step by step, counting the etching wafer number and the opening chamber cleaning number, monitoring the etching rate of the product, and determining that the program can effectively remove the etching by-products. The process can be performed after 100 wafers are processed to open the chamber for wet maintenance, effectively reducing the opening chamber frequency.

[0064] Example 3

[0065] The embodiment provides an ashing-cleaning method for cleaning an etching chamber, comprising the following steps:

[0066] (1) Set the chamber pressure to 100 mToor, adjust the upper electrode power (SrcRFPower) to 1200 W, the lower electrode power (BiasRFPower) to 0 W, and the volume flow rate ratio of Ar, O2 and CF4 to 1:2:2, specifically 100 sccm, 200 sccm and 200 sccm, wherein the O2, Ar and CF4 are introduced by the mixed gas inlet 1 in Figure 4 . The cleaning time is 10 min, and during the cleaning process, the ionized plasma is located in the upper region of the chamber (such as the plasma 9 in Figure 4 ), mainly the chemical reaction of O2 and CF4 mixed ionization to organic matter in the slag, and the slag is removed. This step mainly cleans the upper substrate of the chamber.

[0067] (2) Set the chamber pressure to 100 mToor, adjust the upper electrode power (SrcRFPower) to 1000 W, the lower electrode power (BiasRFPower) to 100 W, and the volume flow rate ratio of Ar and O2 to 1:1, specifically 200 sccm and 200 sccm, wherein the O2 and Ar are introduced by the mixed gas inlet 1 in Figure 5 . The cleaning time is 10 min, and during the cleaning process, the ionized plasma is located in the middle region of the chamber (such as the plasma 9 in Figure 5 ), and this step mainly cleans the sidewall of the chamber.

[0068] (3) Set the chamber pressure to 50 mToor, adjust the upper electrode power (SrcRFPower) to 1000 W, the lower electrode power (BiasRFPower) to 100 W, and the volume flow rate ratio of Ar and O2 to 1:1, specifically 200 sccm and 200 sccm, wherein the O2 and Ar are introduced by the mixed gas inlet 1 in Figure 6 . The cleaning time is 10 min, and during the cleaning process, the ionized plasma is located in the lower region of the chamber (such as the plasma 9 in Figure 6In the plasma (9), this step mainly involves cleaning the lower sidewall of the cavity, the focusing ring, and the Chuck platform.

[0069] Example 4

[0070] This embodiment provides an ashing-cleaning method for cleaning an etching chamber, including the following steps:

[0071] (1) Set the cavity pressure to 90 mToor, adjust the upper electrode power (SrcRFPower) to 1100 W, the lower electrode power (BiasRFPower) to 0 W, and the volumetric flow rate ratio of Ar, O2, and CF4 to 1:2:2, specifically 100 sccm, 200 sccm, and 200 sccm respectively, where O2, Ar, and CF4 are supplied by... Figure 4 The mixed gas is introduced through inlet 1. The cleaning time is 15 minutes. During the cleaning process, CF4 ionizes into highly reactive ion clusters, and the plasma generated by ionization is located in the upper region of the chamber (e.g., Figure 4 The plasma (9) in the chamber mainly involves the chemical reaction between the ionized O2 and CF4 and the organic matter in the glue residue, thus removing the glue residue. This step mainly cleans the upper substrate of the chamber.

[0072] (2) Set the cavity pressure to 80 mToor, adjust the upper electrode power (SrcRFPower) to 900 W, and the lower electrode power (BiasRFPower) to 80 W. The volumetric flow rate ratio of Ar and O2 is 1:1, specifically 200 sccm and 200 sccm respectively, where O2 and Ar are supplied by... Figure 5 The mixed gas is introduced through inlet 1. The cleaning time is 15 minutes. During the cleaning process, the plasma generated by ionization is located in the middle region of the chamber (e.g., Figure 5 In the plasma (9), this step mainly involves cleaning the side walls of the chamber.

[0073] (3) Set the cavity pressure to 30 mToor, adjust the upper electrode power (SrcRFPower) to 900 W, the lower electrode power (BiasRFPower) to 80 W, and the volumetric flow rate ratio of Ar to O2 to be 1:1, specifically 200 sccm and 200 sccm respectively, where O2 and Ar are supplied by... Figure 6 The mixed gas is introduced through inlet 1. The cleaning time is 15 minutes. During the cleaning process, the plasma generated by ionization is located in the lower region of the chamber (e.g., Figure 6 In the plasma (9), this step mainly involves cleaning the lower sidewall of the cavity, the focusing ring, and the Chuck platform.

[0074] The cleaning methods provided in Examples 3 and 4 were used to perform continuous inductively coupled plasma etching, and the results were similar to those in Example 2.

[0075] From the above embodiment, the present application can improve the chamber cleanness, effectively enhance the MTBC of the etching process chamber, ensure the consistency of the etching chamber environment for etching different wafer, the consistency of the process parameters such as etching rate, etching thickness and etching time in the wafer, avoid the abnormal etching process caused by the change of the chamber environment, and affect the subsequent process debugging and product stability.

[0076] Although the above embodiment has made a detailed description of the present application, it is only a part of the embodiments of the present application, not all the embodiments, and other embodiments can be obtained according to the present embodiment without creativity, which all belong to the protection scope of the present application.

Claims

1. An ashing-cleaning method for cleaning an etching chamber, characterized in that, Includes the following steps: (1) The etching chamber is first cleaned by ionization of the first oxygen-containing mixed gas. The first oxygen-containing mixed gas includes inert gas, oxygen and CF4. The volume flow rate ratio of the inert gas, oxygen and CF4 is 1:(0.5~2):(0.5~2). The conditions for the first cleaning include: the chamber pressure is 80~100mToor, the power of the upper electrode is 1000~1200W, and the power of the lower electrode is 0W. (2) The etching chamber is cleaned by ionization of the second oxygen-containing mixed gas. The second oxygen-containing mixed gas includes an inert gas and oxygen. The volume flow rate ratio of the inert gas and oxygen is (1~3):(1~3). The conditions for the second cleaning include: the chamber pressure is 80~100mToor, the power of the upper electrode is 800~1000W, and the power of the lower electrode is 60~100W. (3) The etching chamber is cleaned by ionization of a third oxygen-containing mixed gas. The third oxygen-containing mixed gas includes an inert gas and oxygen. The volume flow rate ratio of the inert gas and oxygen is (1~3):(1~3). The conditions for the third cleaning include: the chamber pressure is 20~50mToor, the power of the upper electrode is 800~1000W, and the power of the lower electrode is 60~100W. There is no time limit for the order of steps (1), (2) and (3).

2. The ashing-cleaning method according to claim 1, characterized in that, The time for the first cleaning, the second cleaning, and the third cleaning is 10-20 minutes each.

3. The ashing-cleaning method according to claim 1, characterized in that, Steps (1), (2), and (3) are performed sequentially.

4. An inductively coupled plasma etching method, characterized in that, The process includes, in sequence: formal wafer loading, etching, formal wafer unloading, bare die loading, cleaning, and bare die unloading; The cleaning is performed using the ashing-cleaning method according to any one of claims 1 to 3.

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