Semiconductor process chamber and cleaning method thereof

Abstract

The present invention provides a cleaning method for a semiconductor process chamber, comprising: controlling a gas supply component to provide a first preset gas to the chamber at a first preset flow rate, and controlling a radio frequency component to ionize the gas to form plasma; controlling a gas supply component to provide a second preset gas to the chamber at a second preset flow rate, maintaining the pressure inside the chamber at the second preset pressure, and controlling the radio frequency component to ionize the second preset gas to form plasma; wherein both the first preset gas and the second preset gas contain oxygen elements, and the first preset flow rate is greater than 100 sccm, the second preset flow rate is less than or equal to 100 sccm, and the second preset pressure is less than or equal to 50 mtorror. The present invention provides a gas containing oxygen elements to the chamber at a low pressure and a low flow rate, and ionizes the gas to form plasma, so that the plasma reaction products left near the nozzle can be cleaned more thoroughly, thereby improving the cleaning effect of the plasma reaction products near the nozzle. The present invention also provides a semiconductor process chamber.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor process equipment, and in particular to a cleaning method for a semiconductor process chamber and a semiconductor process chamber for implementing the cleaning method. Background Art

[0002] As the foundation and core of the information industry, integrated circuits are an overall strategic industry related to the national economy and social development. With the rapid innovation and development of modern chip processing technology, chip output continues to increase, while the structural size continues to decrease. The groove and line width dimensions in the CPU structure composed of chips have been reduced to 5 nanometers or even below 5 nanometers. This requires strict control of particle contamination falling on the wafer during the plasma etching process of the chip, because the groove and line width dimensions in the integrated circuit are very small, and even tiny particles may cause short circuit connections between different etched grooves or holes, disconnection of the same wire, and formation of holes, resulting in greater energy consumption and heat generation. These problems will cause the chip units on the wafer to be scrapped because they cannot be used, thereby reducing the yield of the product.

[0003] Particle control capability is also an important indicator for measuring equipment stability and process stability in integrated circuit technology. In particular, the requirements for particle control in the current advanced process are getting higher and higher, which poses a greater challenge to integrated circuit equipment. The sources of particles mainly include process formation and external introduction. Process formation refers to the introduction during the process reaction. The particles caused by the process include thin film materials etched on the wafer surface for forming IC circuits (for example, silicon dioxide (SiO2), nickel nitride (TiN), etc.), plasma reaction products used for chemical plasma etching (polymer, for example, carbon fluoride (CF), silicon fluoride (Si-F), etc.), and surface materials etched by reaction chamber components (aluminum oxide (Al2O3), yttrium oxide (Y2O3), etc.) and the fall-off of pre-deposited oxide used to protect chamber components during the process; external introduction mainly refers to particle contamination introduced during wafer loading and transmission. In order to extend the cycle of replacing parts, current technology uses a wafer-less automatic dry etching cleaning process (Wafer-less Auto-cleaning, WAC) method to deposit a layer of oxide film on the inner surface of the chamber before the etching process begins. This can greatly reduce the loss of various parts during the etching process, thereby increasing the life of the parts to achieve the needs of reducing costs and stabilizing the chamber etching environment.

[0004] The waferless automatic dry etching cleaning technology first cleans the residual deposited oxide film and the plasma reaction products (polymer) used for chemical plasma etching in the process, and then re-deposits a completely new layer of oxide film to protect the internal components of the chamber. However, due to the structural limitations of the nozzle used in the machine, the currently used waferless automatic dry etching cleaning method does not completely clean the plasma reaction products (polymer) near the nozzle, which in turn causes an increase in the number of particles and special position distribution problems, affecting the production of process product wafers.

[0005] Therefore, how to further improve the cleaning effect of the plasma reaction products near the nozzle has become a technical problem that needs to be solved urgently in this field. Summary of the invention

[0006] The present invention aims to provide a semiconductor process chamber cleaning method and a semiconductor process chamber for implementing the cleaning method. The semiconductor process chamber cleaning method can improve the cleaning effect of plasma reaction products near the nozzle and ensure the cleanliness of the semiconductor process chamber.

[0007] To achieve the above object, as one aspect of the present invention, a method for cleaning a semiconductor process chamber is provided, wherein the semiconductor process chamber comprises a chamber, a gas supply component, a radio frequency component and a nozzle, wherein the gas supply component is used to supply gas into the chamber from the top of the chamber through the nozzle, and the radio frequency component is used to ionize the gas in the chamber to form plasma, and the cleaning method comprises:

[0008] Controlling the gas supply component to provide a first preset gas into the cavity at a first preset flow rate, maintaining the pressure inside the cavity at the first preset pressure for a first preset time, and controlling the radio frequency component to ionize the first preset gas in the cavity to form plasma;

[0009] Controlling the gas supply component to provide a second preset gas into the cavity at a second preset flow rate, maintaining the pressure inside the cavity at the second preset pressure for a second preset time, and controlling the radio frequency component to ionize the second preset gas in the cavity to form plasma;

[0010] Wherein, the first preset gas and the second preset gas both contain oxygen element, and the first preset flow rate is greater than 100 sccm, the second preset flow rate is less than or equal to 100 sccm, and the second preset pressure is less than or equal to 50 mtorr.

[0011] Optionally, the first preset gas and the second preset gas both include oxygen.

[0012] Optionally, the second preset flow rate is 30sccm-80sccm.

[0013] Optionally, the second preset pressure is 10mtorrorr-40mtorrorr.

[0014] Optionally, a second preset time for providing the second preset gas into the cavity is 8-60 seconds.

[0015] Optionally, the RF component includes an upper RF power supply and an upper electrode, the RF power supply is used to provide a RF signal to the inside of the cavity through the upper electrode, and the cleaning method also includes: in the step of providing the second preset gas into the cavity, adjusting the power of the RF power supply to 1000W-2000W.

[0016] Optionally, the nozzle has a central air inlet hole and a plurality of edge air inlet holes surrounding the central air inlet hole, the central air inlet hole is used to spray gas vertically downward, the air supply assembly includes an air supply box and an air supply pipeline, the air supply pipeline includes a first branch, a second branch, a third branch and a fourth branch, wherein the first branch and the second branch are connected in parallel between the air supply box and the central air inlet hole, the third branch and the fourth branch are connected in parallel between the air supply box and the edge air inlet hole, and the minimum flow cross-sectional area of ​​the first branch is smaller than the minimum flow cross-sectional area of ​​the second branch, the minimum flow cross-sectional area of ​​the third branch is equal to the minimum flow cross-sectional area of ​​the second branch, the minimum flow cross-sectional area of ​​the fourth branch is smaller than the minimum flow cross-sectional area of ​​the first branch, and the first branch, the second branch, the third branch and the fourth branch can all be selectively conductive;

[0017] The cleaning method further includes: in the step of providing the second preset gas into the chamber, controlling the first branch, the third branch and the fourth branch to be turned on, and controlling the second branch to be turned off.

[0018] Optionally, the cleaning method further comprises, before the step of providing the first preset gas into the cavity:

[0019] Controlling the gas supply component to provide a third preset gas into the cavity at a third preset flow rate, maintaining the pressure inside the cavity at the third preset pressure for a third preset time, and controlling the radio frequency component to ionize the third preset gas in the cavity to form plasma;

[0020] Wherein, the third preset gas contains fluorine element.

[0021] Optionally, the cleaning method further comprises, after the step of providing the third preset gas into the cavity and before the step of providing the first preset gas into the cavity:

[0022] Controlling the gas supply component to provide a fourth preset gas into the cavity at a fourth preset flow rate, maintaining the pressure inside the cavity at the fourth preset pressure for a fourth preset time, and controlling the radio frequency component to ionize the fourth preset gas in the cavity to form plasma, so as to clean the silicon-oxygen compound film on the surface of the lower half of the structure inside the cavity;

[0023] The fourth preset gas contains fluorine element, the fourth preset flow rate is lower than the third preset flow rate, and the fourth preset pressure is lower than the third preset pressure.

[0024] Optionally, the cleaning method further comprises, after the step of providing the second preset gas into the cavity:

[0025] The gas supply component is controlled to provide a deposition process gas into the cavity for a fifth preset time, and the RF component is controlled to ionize the fifth preset gas in the cavity to form plasma, so as to deposit a protective layer on the components inside the cavity.

[0026] Optionally, the cleaning method further comprises, after the step of providing the deposition process gas into the chamber:

[0027] The gas supply assembly is controlled to provide purge gas into the cavity for a sixth preset time to exhaust gas remaining in the cavity at the end of the previous step.

[0028] As a second aspect of the present invention, a semiconductor process chamber is provided, comprising a chamber, a gas supply component, a radio frequency component and a nozzle, wherein the gas supply component is used to supply gas into the chamber from the top of the chamber through the nozzle, and the radio frequency component is used to ionize the gas in the chamber to form plasma. The semiconductor process chamber also includes a control device, and the control device is used to execute the cleaning method of the semiconductor process chamber described above.

[0029] In the semiconductor process chamber cleaning method and semiconductor process chamber provided by the present invention, the control device can control the gas supply component to provide a process gas containing oxygen elements into the chamber in two steps, so as to ionize and form an oxygen-containing plasma to clean the plasma reaction products. In the first step, a high-flow first preset gas is provided into the chamber to clean the plasma reaction products on the surfaces of most components in the chamber. In the next step, the flow rate of the second preset gas containing oxygen element provided to the chamber is less than or equal to 100 sccm, and during this step, the interior of the chamber is maintained at a second preset pressure less than or equal to 50 mtorror, that is, the gas containing oxygen element is provided to the chamber at a low pressure and a low flow rate, and ionized to form a plasma containing oxygen element, which reduces the rate at which the gas is pushed away from the nozzle by the subsequently introduced gas after ionization to form plasma, thereby increasing the plasma concentration near the nozzle, achieving a more thorough cleaning of the plasma reaction products containing carbon, hydrogen and other elements remaining near the nozzle at a low flow rate and low pressure, improving the cleaning effect of the plasma reaction products near the nozzle (especially at the edge air inlet), thereby ensuring the cleanliness of the semiconductor process chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0031] Figure 1 is a schematic structural diagram of a semiconductor process chamber provided by an embodiment of the present invention;

[0032] Figure 2 It is a structural schematic diagram of a gas supply pipeline of a gas supply assembly in a semiconductor process chamber provided by an embodiment of the present invention;

[0033] Figure 3 It is a schematic flow chart of a method for cleaning a semiconductor process chamber provided by an embodiment of the present invention;

[0034] Figure 4 It is a schematic diagram of the effect of cleaning a semiconductor process chamber using the semiconductor process chamber cleaning method provided by an embodiment of the present invention;

[0035] Figure 5 is a schematic flow chart of a method for cleaning a semiconductor process chamber provided by another embodiment of the present invention;

[0036] Figure 6 is a schematic structural diagram of a nozzle in a semiconductor process chamber provided by an embodiment of the present invention;

[0037] Figure 7 is a cross-sectional schematic diagram of a nozzle in a semiconductor process chamber provided by an embodiment of the present invention;

[0038] Figure 8 yes Figure 7 A partial enlarged schematic diagram of area A in the middle. DETAILED DESCRIPTION

[0039] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0040] The inventors of the present invention have found through research that the main reason why the cleaning efficiency of the plasma reaction product (polymer) near the nozzle in the prior art is low is that, in the step of cleaning the plasma reaction product in the process chamber, the plasma on the nozzle surface is not thoroughly cleaned. Specifically:

[0041] The existing waferless automatic dry etching cleaning process mainly includes the following steps:

[0042] Step 01: The deposited oxide coating remaining on the surface of the internal components of the chamber (such as the dielectric window, the nozzle (inject), the gas distribution plate (GDP), the liner, the electrostatic chuck (ESC), etc.) is subjected to a micro-roughening cleaning treatment, specifically comprising: first, without applying a bias voltage (only the upper radio frequency power (SRF power) exists), the first vacuum pressure and fluorine-containing plasma are used to perform a plasma reaction cleaning on the oxide film layer remaining on the components in the upper part of the chamber (the dielectric window, the gas distribution plate, etc.), so that the surface of the components is subjected to a micro-roughening treatment; secondly, without applying a bias voltage, the second vacuum pressure and fluorine-containing plasma are used to perform a plasma reaction cleaning on the components in the lower half of the chamber (the electrostatic chuck, the liner, the inner wall of the chamber, etc.) and the oxide film layer remaining on the upper component nozzle, so that the surface of the components in the lower half of the chamber and the injector is subjected to a micro-roughening treatment.

[0043] Step 02: Performing a micro-roughening cleaning treatment on the plasma reaction products (polymer) generated during the process of the internal components of the chamber, specifically comprising: using vacuum pressure and oxygen-containing plasma to perform plasma reaction cleaning on the plasma reaction products on the components inside the chamber without applying a bias voltage, so that the surface of the components is micro-roughened;

[0044] Step 03: After the residual deposited oxide coating inside the chamber and the plasma reaction products generated during the process are completely cleaned, oxide film deposition is performed on the coated parts on the inner wall of the etching chamber so that the surface of the parts adsorbs silicon oxide compounds and reaches a saturated state, thereby protecting the internal parts of the chamber and stabilizing the chamber process environment.

[0045] Step 04: After the oxide film deposition in step 03 is completed, an inert gas is introduced into the chamber to purge the remaining special gases (such as SiCl4, Cl2, etc.) out of the chamber to prevent the remaining special gases from affecting the product wafers in the process.

[0046] In step S02, in order to ensure the cleaning effect of the plasma reaction products on the components inside the chamber, the supply flow rate of the gas (such as oxygen) used to ionize and form the oxygen-containing plasma is usually large (for example, the oxygen flow rate is generally not less than 200 sccm).

[0047] However, if Figures 6 to 8 As shown, the nozzle 200 has a central air inlet hole 210 and a plurality of edge air inlet holes 220 surrounding the central air inlet hole 210, wherein the central air inlet hole 210 is used to spray gas vertically downward, and the edge air inlet holes 220 are used to spray gas obliquely downward in all directions, so that the plasma generated by the process gas can be more evenly distributed above the wafer and gradually diffuse to the surface of the wafer to undergo corresponding reactions.

[0048] Due to the special structure of the edge air inlet hole 220, the plasma reaction product (polymer) is loosely attached to the side walls and corners of the edge air inlet hole 220. In this case, the higher the gas pressure and the greater the flow rate of the process gas provided, the weaker the cleaning effect on the lower part of the chamber and near the edge hole of the nozzle, resulting in a lower cleaning efficiency of the plasma reaction products near the nozzle.

[0049] To solve the above technical problems, as one aspect of the present invention, a method for cleaning a semiconductor process chamber is provided, such as Figure 1 As shown, the semiconductor process chamber includes a chamber 100, a gas supply component, a radio frequency component and a nozzle 200. The gas supply component is used to provide gas from the top of the chamber 100 to the chamber 100 through the nozzle 200, and the radio frequency component is used to ionize the gas in the chamber 100 to form plasma. Figure 3 As shown, the cleaning method comprises:

[0050] Step S10, controlling the gas supply component to provide a first preset gas into the cavity 100 at a first preset flow rate, maintaining the pressure inside the cavity 100 at the first preset pressure for a first preset time, and controlling the RF component to ionize the first preset gas in the cavity 100 to form plasma;

[0051] Step S20, controlling the gas supply component to provide a second preset gas into the cavity 100 at a second preset flow rate, maintaining the pressure inside the cavity 100 at the second preset pressure for a second preset time, and controlling the RF component to ionize the second preset gas in the cavity 100 to form plasma;

[0052] The first preset gas and the second preset gas both contain oxygen, and the first preset flow rate is greater than 100 sccm, the second preset flow rate is less than or equal to 100 sccm, and the second preset pressure is less than or equal to 50 mtorr.

[0053] In the semiconductor process chamber cleaning method provided by the present invention, in both step S10 and step S20, a process gas containing oxygen is provided to the chamber 100, so as to ionize and form an oxygen-containing plasma to clean the plasma reaction product (polymer). In step S10, a first preset gas with a high flow rate (greater than 100 sccm) is provided to the chamber 100 to clean the plasma reaction product on the surfaces of most components in the chamber 100. In step S20, the flow rate of the second preset gas containing oxygen element provided to the chamber 100 is less than or equal to 100 sccm, and during step S20, the interior of the chamber 100 is maintained at a second preset pressure less than or equal to 50 mtorror, that is, the gas containing oxygen element is provided to the chamber 100 at a low pressure and a low flow rate, and is ionized to form a plasma containing oxygen element, thereby reducing the rate at which the gas is pushed away from the nozzle 200 by the subsequently introduced gas after ionization to form plasma, thereby increasing the plasma concentration near the nozzle 200, achieving a more thorough cleaning of the plasma reaction products containing elements such as carbon (C) and hydrogen (H) remaining near the nozzle 200 at a low flow rate and low pressure, thereby improving the cleaning effect of the plasma reaction products near the nozzle 200 (especially at the edge air inlet 220), thereby ensuring the cleanliness of the semiconductor process chamber.

[0054] As an optional embodiment of the present invention, Figure 1 As shown, the RF component includes an upper RF power supply (not shown) and an upper electrode 300 (coil), and the RF power supply is used to provide a RF signal to the inside of the cavity 100 through the upper electrode 300 .

[0055] Considering that the plasma reaction products left near the nozzle 200 mainly contain carbon and hydrogen elements, in order to facilitate the exhaust of the tail gas, as a preferred embodiment of the present invention, the first preset gas and the second preset gas both include oxygen. In the embodiment of the present invention, the first preset gas and the second preset gas are oxygen, which has a better reaction effect with the organic matter mainly containing carbon and hydrogen elements near the nozzle 200, and no byproducts that are difficult to remove are generated during the cleaning process, further ensuring the cleanliness of the chamber environment.

[0056] In the present invention, low flow rate is a key factor to ensure the removal effect of the plasma reaction products near the nozzle 200. Too large or too small a flow rate cannot achieve an ideal cleaning effect. As a preferred embodiment of the present invention, the second preset flow rate is 30sccm-80sccm (standard cubic centimeter per minute).

[0057] Low pressure is another key factor to ensure the removal effect of the plasma reaction products near the nozzle 200. In the present invention, increasing the power of the upper electrode 300 can only increase the ionization degree of the gas and increase the plasma density, thereby increasing the reaction rate between the plasma and the plasma reaction products, and correspondingly shortening the process time. When the flow rate and pressure are too large, the upper electrode 300 power cannot achieve the ideal cleaning effect. Therefore, it is necessary to ensure that the second preset pressure is within the required range. As a preferred embodiment of the present invention, the second preset pressure is 10mtorrorr-40mtorrorr.

[0058] As an optional embodiment of the present invention, the second preset time for providing the second preset gas to the chamber 100 is 8-60 seconds. The duration of providing the second preset gas to the chamber 100 can be freely adjusted within a range according to process requirements. For example, when the thickness of the plasma reaction product to be cleaned near the nozzle 200 is high, the duration of providing the second preset gas to the chamber 100 can be set to be longer accordingly. When the thickness of the plasma reaction product to be cleaned near the nozzle 200 is low, the duration of providing the second preset gas to the chamber 100 can be shortened accordingly.

[0059] In order to ensure the cleaning effect of the plasma reaction product near the nozzle 200 in step S20, the power of the upper electrode 300 in step S20 can be increased accordingly. Specifically, as shown in Table 1-1, the cleaning method further includes:

[0060] In the step S20 of providing the second preset gas into the chamber 100 , the power of the radio frequency power source is adjusted to 1000W-2000W.

[0061] The process parameters corresponding to step S20 are shown in Table 1-1 below:

[0062] Table 1-1

[0063] Step Pressure(mtorr) Power(W) Gas(sccm) ESC temp(℃) IR FRC ratio Time(s) S20 10-40 1000-2000 30-80O2 / 50He_Edge 60 / 60 / 60 / 60 0.43 Edge 8-60

[0064] As an optional implementation of the present invention, the first preset gas is oxygen, the first preset flow rate is 200 sccm, and the first preset time may be 14 s.

[0065] Compared with the second preset pressure (low pressure) required in step S20, the upper limit of the range of the first preset pressure in step S10 can be higher. As an optional embodiment of the present invention, the first preset pressure can be any value less than 65 mtorr. For example, optionally, in step S10, the pressure inside the cavity 100 is maintained at 15 mtorr.

[0066] The range of the first preset flow rate in step S10 can be selected according to the meter range. For example, in a conventional semiconductor process chamber, the maximum range of the flow meter on the air inlet line can usually be selected as 500 sccm, and the value range of the first preset flow rate can be 100 sccm to 400 sccm. Optionally, the first preset flow rate can be 200 sccm.

[0067] In step S10 of providing the first preset gas into the cavity 100, the power range of the RF power supply may be similar to that of step S20. For example, as an optional embodiment of the present invention, the power of the RF power supply may be adjusted to 1000W in step S10.

[0068] The process parameters corresponding to step S10 are shown in Table 1-2 below:

[0069] Table 1-2

[0070] Step Pressure(mtorr) Power(W) Gas(sccm) ESC temp(℃) IR FRC ratio Time(s) S10 15 1000W 200O2 / 50He_Edge 60 / 60 / 60 / 60 0.43 Edge 14

[0071] As an optional embodiment of the present invention, Figure 1 As shown, the semiconductor process chamber also includes a liner 120, an electrostatic chuck 110 (electrostatic chuck, ESC), a dielectric window 400 (window) and a gas distribution plate 500 (gas distribution plate, GDP), the liner 120 is used to protect the inner wall of the chamber 100, the electrostatic chuck 110 is used to carry a wafer 111 (wafer), the dielectric window 400 closes the top opening of the chamber 100, the annular gas distribution plate 500 is arranged inside the chamber 100, the nozzle 200 passes through the through hole on the dielectric window 400 and through the inner hole in the center of the gas distribution plate 500 to uniformly spray process gas into the chamber 100, the upper electrode 300 is arranged above the dielectric window 400, and the radio frequency signal is fed into the chamber 100 through the dielectric window 400.

[0072] As an optional embodiment of the present invention, the cleaning method further comprises the step of performing a micro-roughening cleaning treatment on the deposited oxide coating remaining on the surface of the internal components of the chamber by using a fluorine-containing plasma. Specifically, Figure 5 As shown, the cleaning method further includes the following steps before step S10 of providing the first preset gas into the chamber 100:

[0073] Step S01: Control the gas supply component to provide a third preset gas into the cavity 100 at a third preset flow rate, maintain the pressure inside the cavity 100 at the third preset pressure for a third preset time, and control the RF component to ionize the third preset gas in the cavity 100 to form plasma; wherein the third preset gas contains fluorine element.

[0074] As an optional implementation of the present invention, the third preset gas containing fluorine element in step S01 may be nitrogen trifluoride.

[0075] Considering that the higher the gas pressure and the greater the flow rate, the weaker the cleaning effect on the lower part of the chamber (electrostatic chuck 110, corners of liner 120, etc.) and near the edge air inlet, and the better the cleaning effect on the residual film layer on the upper surface of the chamber, especially near the dielectric window 400. Under the same time conditions, low-pressure and low-flow gas, due to its lower flow rate, can better clean the corners of the lower surface of the chamber and near the nozzle 200. In order to improve the overall cleaning effect, as a preferred embodiment of the present invention, a high-low pressure combination method can be used to clean the residual oxides on the upper and lower surfaces of the chamber.

[0076] Specifically, Figure 5 As shown, the cleaning method further includes the following steps after step S01 of providing the third preset gas into the chamber 100 and before step S10 of providing the first preset gas into the chamber 100:

[0077] Step S02, control the gas supply component to provide the fourth preset gas to the cavity 100 at a fourth preset flow rate, maintain the pressure inside the cavity 100 at the fourth preset pressure for a fourth preset time, and control the RF component to ionize the fourth preset gas in the cavity 100 to form plasma, so as to clean the silicon-oxygen compound film on the surface of the lower half of the structure inside the cavity 100 (and near the nozzle 200). The fourth preset gas contains fluorine, and the fourth preset flow rate is lower than the third preset flow rate, and the fourth preset pressure is lower than the third preset pressure. In this case, the main effect of step S01 is to clean the silicon-oxygen compound film on the surface of the upper half of the structure inside the cavity 100, that is, step S01 and step S02 form a high-low pressure combined cleaning process, and the silicon-oxygen compound film attached to the surface of the structure in different areas inside the cavity 100 is cleaned respectively.

[0078] Optionally, the fourth preset gas is also nitrogen trifluoride.

[0079] The process parameters corresponding to step S01 are shown in Table 1-3 below, and the process parameters corresponding to step S02 are shown in Table 1-4 below:

[0080] Table 1-3

[0081] Step Pressure(mtorr) Power(W) Gas(sccm) ESC temp(℃) IR FRC ratio Time(s) S01 400 1800W 500NF3 / 200Ar / 50He_Edge 60 / 60 / 60 / 60 0.43 Edge 20

[0082] Table 1-4

[0083] Step Pressure(mtorr) Power(W) Gas(sccm) ESC temp(℃) IR FRC ratio Time(s) S02 65 1800W 50NF3 / 50He_Edge 60 / 60 / 60 / 60 0.43 Edge 12

[0084] As shown in Tables 1-3 and 1-4, the third preset flow rate of the third preset gas (nitrogen trifluoride) in step S01 is set to a relatively high value (500 sccm), and the fourth preset flow rate of the fourth preset gas (nitrogen trifluoride) in step S02 is set to a relatively low value (50 sccm), and the internal pressure of the process chamber in step S01 (400 mtorr) is higher than the internal pressure of the process chamber in step S02 (65 mtorr), that is, step S01 is in a high pressure, high flow mode, and step S02 is in a low pressure, low flow mode, so that in step S01, the residual film layer containing silicon oxide compounds near the dielectric window 400 (i.e., the upper half structure inside the cavity 100) is mainly cleaned, and in step S02, the corners of the lower surface of the chamber (i.e., the lower half structure inside the cavity 100) and near the nozzle 200 are mainly cleaned to improve the cleaning effect of the entire chamber.

[0085] Optionally, the third preset time is 20 seconds, and the fourth preset time is 12 seconds; in both step S01 and step S02, the power of the RF power supply is adjusted to 1800 W. As an optional embodiment of the present invention, the cleaning method further includes providing a preset inert gas at a preset flow rate into the cavity 100 in the step of providing the second preset gas, the third preset gas, the fourth preset gas and the first preset gas into the cavity 100.

[0086] As an optional embodiment of the present invention, as shown in Tables 1-1 to 1-4, the preset inert gas is helium, and the preset flow rate is 50 sccm.

[0087] In order to extend the service life of the internal components of the cavity 100, the method further includes the step of depositing an oxide film protective layer inside the cavity 100, specifically, as Figure 5 As shown, the method further includes the following steps after step S20 of providing a second preset gas into the cavity 100:

[0088] Step S30, controlling the gas supply component to provide deposition process gas into the cavity 100 for a fifth preset time, and controlling the RF component to ionize the fifth preset gas in the cavity 100 to form plasma, so as to deposit a protective layer on the internal components of the cavity 100.

[0089] Optionally, the fifth preset time may be 12 seconds, and the deposition process gas may include silicon tetrachloride and oxygen. Silicon tetrachloride and oxygen form plasma and react to generate a dense silicon oxide film layer and deposit it on the chamber surface.

[0090] Optionally, the method further includes maintaining the pressure inside the chamber 100 at 50 mtorr and adjusting the power of the RF power supply to 1350W in the step S30 of providing the deposition process gas into the chamber 100 .

[0091] The process parameters corresponding to step S30 are shown in Table 1-5 below:

[0092] Table 1-5

[0093] Step Pressure(mtorr) Power(W) Gas(sccm) ESC temp(℃) IR FRC ratio Time(s) S30 50 1350W 100SiCl4 / 200O2 / 300Ar / 50He_Edge 60 / 60 / 60 / 60 0.79 Center 12

[0094] As an optional embodiment of the present invention, the method further comprises the step of blowing out the residual gas in the chamber, specifically, as follows Figure 5 As shown, the method also includes:

[0095] Step S40 , controlling the gas supply assembly to provide purge gas into the chamber 100 for a sixth preset time to exhaust the gas remaining in the chamber 100 at the end of the previous step.

[0096] Optionally, the sixth preset time is 15 seconds, and the purge gas may include at least one inert gas (eg, helium, argon, etc.). The process parameters corresponding to step S40 are shown in Table 1-6 below:

[0097] Table 1-6

[0098] Step Pressure(mtorr) Power(W) Gas(sccm) ESC temp(℃) IR FRC ratio Time(s) S40 Position mode: 1000 0W 500Ar / 50He_Edge 60 / 60 / 60 / 60 0.79 Center 15

[0099] As an optional embodiment of the present invention, Figures 6 to 8 As shown, the nozzle 200 has a central air inlet hole 210 and a plurality of edge air inlet holes 220 surrounding the central air inlet hole 210 , and the central air inlet hole 210 is used to spray gas vertically downward.

[0100] Specifically, Figure 7 , Figure 8 As shown, the top of the nozzle 200 is used to receive the process gas, and the inside of the nozzle 200 has a first central air guide hole 211, a plurality of second central air guide holes 212, and a plurality of edge air guide holes 221 extending in the vertical direction. The tops of the plurality of second central air guide holes 212 are connected to the bottoms of the first central air guide holes 211, the bottoms of the plurality of second central air guide holes 212 are connected to the plurality of central air inlet holes 210 in a one-to-one correspondence, and the bottoms of the plurality of edge air guide holes 221 are connected to the plurality of edge air inlet holes 220 in a one-to-one correspondence. Part of the process gas entering from the top of the nozzle 200 passes through the first central air guide hole 211, the plurality of second central air guide holes 212, and the plurality of central air inlet holes 210 in sequence and is discharged into the cavity 100, and another part of the process gas passes through the plurality of edge air guide holes 221 and the plurality of edge air inlet holes 220 in sequence and is discharged into the cavity 100.

[0101] The gas supply assembly includes a gas box and a gas supply pipeline, such as Figure 2 As shown, the air supply pipeline includes a first branch 610, a second branch 620, a third branch 630 and a fourth branch 640, wherein the first branch 610 and the second branch 620 are connected in parallel between the air supply box and the central air inlet hole 210, the third branch 630 and the fourth branch 640 are connected in parallel between the air supply box and the edge air inlet hole 220, and the minimum flow cross-sectional area of ​​the first branch 610 is smaller than the minimum flow cross-sectional area of ​​the second branch 620, the minimum flow cross-sectional area of ​​the third branch 630 is equal to the minimum flow cross-sectional area of ​​the second branch 620, and the minimum flow cross-sectional area of ​​the fourth branch 640 is smaller than the minimum flow cross-sectional area of ​​the first branch 610, and the first branch 610, the second branch 620, the third branch 630 and the fourth branch 640 can all be selectively conducted.

[0102] As an optional embodiment of the present invention, Figure 2 As shown, the first branch 610, the second branch 620, the third branch 630 and the fourth branch 640 are all provided with gas proportion adjustment gaskets (Orifice) for limiting the minimum flow cross-sectional area on the branches, and the flow limiting aperture of the proportion adjustment gasket 611 on the first branch 610 is smaller than the flow limiting aperture of the proportion adjustment gasket 621 on the second branch 620, the flow limiting aperture of the proportion adjustment gasket 631 on the third branch 630 is equal to the flow limiting aperture of the proportion adjustment gasket 621 on the second branch 620, and the flow limiting aperture of the proportion adjustment gasket 641 on the fourth branch 640 is smaller than the flow limiting aperture of the proportion adjustment gasket 611 on the first branch 610.

[0103] For example, optionally, the limiting aperture of the proportional adjustment gasket 611 on the first branch 610 is 1.6 mm, the limiting aperture of the proportional adjustment gasket 641 on the fourth branch 640 is 1 mm, and the limiting apertures of the proportional adjustment gasket 621 on the second branch 620 and the proportional adjustment gasket 631 on the third branch 630 are both 4.3 mm.

[0104] As an optional embodiment of the present invention, Figure 2 As shown, the on-off of the branch can be controlled by setting a pneumatic valve (AirValve) on the branch.

[0105] Accordingly, the air intake amount of the central air inlet hole 210 and the edge air inlet hole 220 of the nozzle 200 can be changed by adjusting the on and off of the first branch 610, the second branch 620, the third branch 630 and the fourth branch 640. Specifically, the mode (FRC ratio) of the gas in the gas supply box entering the chamber can be divided into four types:

[0106] Equal mode: the four-branch gas is fully open, that is, the first branch 610, the second branch 620, the third branch 630 and the fourth branch 640 are all open;

[0107] Center mode: the pneumatic valve 622 of the second branch 620 with a flow limiting aperture of 4.3 mm of the gas ratio adjustment gasket connected to the central air inlet 210 is opened, and the pneumatic valve 632 of the third branch 630 with a flow limiting aperture of 4.3 mm connected to the edge air inlet 220 is closed, and the branches with flow limiting apertures of 1.6 mm and 1.0 mm are normally open, that is, the first branch 610, the second branch 620 and the fourth branch 640 are opened, and the third branch 630 is closed;

[0108] Edge mode: the pneumatic valve 632 of the third branch 630 with a flow limiting aperture of 4.3 mm of the gas ratio adjustment gasket connected to the edge air inlet 220 is opened, and the pneumatic valve 622 of the second branch 620 with a flow limiting aperture of 4.3 mm connected to the central air inlet 210 is closed, and the branches with flow limiting apertures of 1.6 mm and 1.0 mm are normally open, that is, the first branch 610, the third branch 630 and the fourth branch 640 are opened, and the second branch 620 is closed;

[0109] Less center mode: the pneumatic valves of the two branches with a flow limiting aperture of 4.3 mm of the gas ratio adjustment gasket connecting the central air inlet 210 and the edge air inlet 220 are both closed, and the branches with flow limiting apertures of 1.6 mm and 1.0 mm are normally open, that is, the first branch 610 and the fourth branch 640 are open, and the second branch 620 and the third branch 630 are closed.

[0110] As an optional embodiment of the present invention, the cleaning method also includes: in step S20 of providing a second preset gas into the cavity 100, controlling the first branch 610, the third branch 630 and the fourth branch 640 to be turned on, and controlling the second branch 620 to be turned off, that is, the air intake mode (FRC ratio) of the gas supply component in step S20 is Edge mode.

[0111] Optionally, the air supply component is in Center mode only in step S30 and step S40, and is in Edge mode in the remaining steps.

[0112] Alternatively, if Figure 2 As shown, the air supply pipeline also includes an air intake main pipe. The upstream of the first branch 610, the second branch 620, the third branch 630 and the fourth branch 640 are all connected to the air supply box through the air intake main pipe. A filter 651 (filter) and a main pneumatic valve 652 are provided on the air intake main pipe.

[0113] Optionally, as shown in Tables 1-1 to 1-6, the temperature (ESC temp) of the electrostatic chuck (ESC) is maintained at 60°C in each step (specifically, the four temperature control zones of the electrostatic chuck are all maintained at 60°C, that is, the process parameters are set to 60 / 60 / 60 / 60).

[0114] Optionally, the upper electrode 300 includes an inner RF coil and an outer RF coil horizontally surrounding the outer side of the inner RF coil. As shown in Table 1-1 to Table 1-6, in steps S01 to S20, the outer coil current ratio parameter IR (i.e., the ratio of the current value on the outer RF coil to the sum of the current values ​​on the inner RF coil and the outer RF coil) is maintained at 0.43, and in the remaining steps, the outer coil current ratio parameter IR is maintained at 0.79.

[0115] like Figure 4 The figure is a comparative diagram of the number of particles on the wafer surface obtained when step S20 is not performed and when step S20 is performed using the process recipe shown in Table 1-7 below.

[0116] Table 1-7

[0117] Step Pressure(mtorr) Power(W) Gas(sccm) ESC temp(℃) IR FRC ratio Time(s) S20 15 1000 40O2 / 50He_Edge 60 / 60 / 60 / 60 0.43 Edge 8or 40

[0118] Depend on Figure 4 It can be seen that the cleaning process using the waferless automated dry etch cleaning (WAC) recipe including step S20 can significantly reduce the number of particles on the wafer, especially when the second preset time is extended to 40s, the number of wafer particles is almost zero.

[0119] As a second aspect of the present invention, a semiconductor process chamber is provided, comprising a chamber 100, a gas supply assembly, a radio frequency assembly and a nozzle 200, wherein the gas supply assembly is used to provide gas into the chamber 100 from the top of the chamber 100 through the nozzle 200, and the radio frequency assembly is used to ionize the gas in the chamber 100 to form plasma. The semiconductor process chamber also includes a control device, which is used to execute the cleaning method of the semiconductor process chamber provided in an embodiment of the present invention.

[0120] In the semiconductor process chamber provided by the present invention, the control device can control the gas supply assembly to provide a process gas containing oxygen elements into the chamber 100 in two steps, so as to ionize and form an oxygen-containing plasma to clean the plasma reaction products. In the first step, a first preset gas with a high flow rate (greater than 100 sccm) is provided into the chamber 100 to clean the plasma reaction products on the surfaces of most components in the chamber 100. In the next step, the flow rate of the second preset gas containing oxygen element provided to the chamber 100 is less than or equal to 100 sccm, and during this step, the interior of the chamber 100 is maintained at a second preset pressure less than or equal to 50 mtorror, that is, the gas containing oxygen element is provided to the chamber 100 at a low pressure and a low flow rate, and ionized to form a plasma containing oxygen element, thereby reducing the rate at which the gas is pushed away from the nozzle 200 by the subsequently introduced gas after ionization to form plasma, thereby increasing the plasma concentration near the nozzle 200, achieving a more thorough cleaning of the plasma reaction products containing elements such as carbon (C) and hydrogen (H) remaining near the nozzle 200 at a low flow rate and low pressure, thereby improving the cleaning effect of the plasma reaction products near the nozzle 200 (especially at the edge air inlet 220), thereby ensuring the cleanliness of the semiconductor process chamber.

[0121] As an optional embodiment of the present invention, the nozzle 200 has a central air inlet hole 210 and a plurality of edge air inlet holes 220 surrounding the central air inlet hole 210, the central air inlet hole 210 is used to spray gas vertically downward, and the air supply assembly includes an air supply box and an air supply pipeline. Figure 2 As shown, the air supply pipeline includes a first branch 610, a second branch 620, a third branch 630 and a fourth branch 640, wherein the first branch 610 and the second branch 620 are connected in parallel between the air supply box and the central air inlet hole 210, the third branch 630 and the fourth branch 640 are connected in parallel between the air supply box and the edge air inlet hole 220, and the minimum flow cross-sectional area of ​​the first branch 610 is smaller than the minimum flow cross-sectional area of ​​the second branch 620, the minimum flow cross-sectional area of ​​the third branch 630 is equal to the minimum flow cross-sectional area of ​​the second branch 620, and the minimum flow cross-sectional area of ​​the fourth branch 640 is smaller than the minimum flow cross-sectional area of ​​the first branch 610, and the first branch 610, the second branch 620, the third branch 630 and the fourth branch 640 can all be selectively conducted.

[0122] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for cleaning a semiconductor process chamber, the semiconductor process chamber comprising a chamber, a gas supply component, a radio frequency component and a nozzle, the gas supply component is used to provide gas into the chamber from the top of the chamber through the nozzle, the radio frequency component is used to ionize the gas in the chamber to form plasma, characterized in that: The cleaning method comprises: Controlling the gas supply component to provide a first preset gas into the cavity at a first preset flow rate, maintaining the pressure inside the cavity at the first preset pressure for a first preset time, and controlling the radio frequency component to ionize the first preset gas in the cavity to form plasma; Controlling the gas supply component to provide a second preset gas into the cavity at a second preset flow rate, maintaining the pressure inside the cavity at the second preset pressure for a second preset time, and controlling the radio frequency component to ionize the second preset gas in the cavity to form plasma; Wherein, the first preset gas and the second preset gas both contain oxygen element, and the first preset flow rate is greater than 100 sccm, the second preset flow rate is less than or equal to 100 sccm, and the second preset pressure is less than or equal to 50 mtorr.

2. The method for cleaning a semiconductor process chamber according to claim 1, wherein: The first preset gas and the second preset gas both include oxygen.

3. The method for cleaning a semiconductor process chamber according to claim 2, wherein: The second preset flow rate is 30 sccm-80 sccm.

4. The method for cleaning a semiconductor process chamber according to claim 1, wherein: The second preset pressure is 10mtorrorr-40mtorrorr.

5. The method for cleaning a semiconductor process chamber according to any one of claims 1 to 4, characterized in that: The second preset time for providing the second preset gas into the cavity is 8-60 seconds.

6. The method for cleaning a semiconductor process chamber according to claim 5, wherein: The RF component includes an upper RF power supply and an upper electrode, and the RF power supply is used to provide an RF signal to the inside of the cavity through the upper electrode. The cleaning method also includes: in the step of providing the second preset gas into the cavity, adjusting the power of the RF power supply to 1000W-2000W.

7. The method for cleaning a semiconductor process chamber according to any one of claims 1 to 4, characterized in that: The nozzle has a central air inlet hole and a plurality of edge air inlet holes surrounding the central air inlet hole, the central air inlet hole is used to spray gas vertically downward, the air supply assembly includes an air supply box and an air supply pipeline, the air supply pipeline includes a first branch, a second branch, a third branch and a fourth branch, wherein the first branch and the second branch are connected in parallel between the air supply box and the central air inlet hole, the third branch and the fourth branch are connected in parallel between the air supply box and the edge air inlet hole, and the minimum flow cross-sectional area of ​​the first branch is smaller than the minimum flow cross-sectional area of ​​the second branch, the minimum flow cross-sectional area of ​​the third branch is equal to the minimum flow cross-sectional area of ​​the second branch, and the minimum flow cross-sectional area of ​​the fourth branch is smaller than the minimum flow cross-sectional area of ​​the first branch, and the first branch, the second branch, the third branch and the fourth branch can all be selectively conducted; The cleaning method further includes: in the step of providing the second preset gas into the chamber, controlling the first branch, the third branch and the fourth branch to be turned on, and controlling the second branch to be turned off.

8. The method for cleaning a semiconductor process chamber according to any one of claims 1 to 4, characterized in that: The cleaning method further comprises, before the step of providing the first preset gas into the chamber: Controlling the gas supply component to provide a third preset gas into the cavity at a third preset flow rate, maintaining the pressure inside the cavity at the third preset pressure for a third preset time, and controlling the radio frequency component to ionize the third preset gas in the cavity to form plasma; Wherein, the third preset gas contains fluorine element.

9. The method for cleaning a semiconductor process chamber according to claim 8, wherein: The cleaning method further comprises, after the step of providing the third preset gas into the cavity and before the step of providing the first preset gas into the cavity: Controlling the gas supply component to provide a fourth preset gas into the cavity at a fourth preset flow rate, maintaining the pressure inside the cavity at a fourth preset pressure for a fourth preset time, and controlling the radio frequency component to ionize the fourth preset gas in the cavity to form plasma; The fourth preset gas contains fluorine element, the fourth preset flow rate is lower than the third preset flow rate, and the fourth preset pressure is lower than the third preset pressure.

10. The method for cleaning a semiconductor process chamber according to claim 9, wherein: The cleaning method further comprises, after the step of providing the second preset gas into the chamber: The gas supply component is controlled to provide a deposition process gas into the cavity for a fifth preset time, and the radio frequency component is controlled to ionize the fifth preset gas in the cavity to form plasma, so as to deposit a protective layer on the components inside the cavity.

11. The method for cleaning a semiconductor process chamber according to claim 10, wherein: The cleaning method further comprises, after the step of providing the deposition process gas into the chamber: The gas supply assembly is controlled to provide purge gas into the cavity for a sixth preset time to exhaust gas remaining in the cavity at the end of the previous step.

12. A semiconductor process chamber, comprising a chamber, a gas supply component, a radio frequency component and a nozzle, wherein the gas supply component is used to supply gas into the chamber from the top of the chamber through the nozzle, and the radio frequency component is used to ionize the gas in the chamber to form plasma, characterized in that: The semiconductor process chamber further comprises a control device, wherein the control device is used to execute the semiconductor process chamber cleaning method according to any one of claims 1 to 11.

Images