Process chamber cleaning method
By introducing NF3 gas into the process chamber to form a silicon-rich protective layer, and using high-frequency and low-frequency radio frequency to ionize the residues, suspending the plasma, and then removing the residues with inert gas, the problem of wafer edge contamination in the process chamber cleaning process is solved, and the wafer yield is improved.
Patent Information
- Application Number
- CN202511050288.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-29
- Publication Date
- 2025-11-11
AI Technical Summary
During the preparation of low dielectric constant oxide layers, residual precursor gases and byproducts from the initial cleaning process of the process chamber contaminate the wafer edge region, leading to a decrease in wafer yield.
By introducing NF3 gas into the process chamber for plasma treatment, a silicon-rich protective layer is formed. The residue is then ionized using high-frequency and low-frequency radio frequency, and after the plasma is suspended, it is purged with inert gas to remove the residue and prevent contamination.
It effectively removes residues from the process chamber, improves the reliability of the CVD preparation process in the process chamber, and increases wafer yield.
Smart Images
Figure CN120933146A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor manufacturing technology, and more specifically to a method for cleaning a process chamber. Background Technology
[0002] With the continuous advancement of semiconductor manufacturing processes, the density of integrated circuits is increasing, and the number of conductor interconnects is also increasing. The resistive-capacitive delay (RC delay) phenomenon caused by metal interconnects is becoming more and more serious. Low-K (low dielectric constant) dielectric layers, due to their low dielectric constant (typically k<3), can effectively reduce parasitic resistance and parasitic capacitance, and reduce delay, and are widely used in semiconductor production.
[0003] During the initial cleaning process of the process chamber used to prepare the low dielectric constant oxide (LKO) layer, a precursor gas (such as OMCTS gas) is introduced to form a dense protective film on the inner wall of the process chamber. However, the initial cleaning process inevitably leaves some precursor gas and byproducts inside the process chamber. These residual OMCTS gas and byproducts are easily blown by the gas flow to the edge area of the wafer surface during the subsequent preparation of the LKO layer. This forms embedded impurity particles in the wafer edge area, thus contaminating the wafer surface and affecting the subsequent wafer yield. Summary of the Invention
[0004] This application provides a method for cleaning process chambers, which can solve the problem that residual precursor gases and byproducts from the early cleaning of process chambers during the preparation of low dielectric constant oxide (LKO) layers contaminate the wafer edge area, thus affecting wafer yield.
[0005] This application provides a method for cleaning a process chamber, including:
[0006] NF3 gas is introduced into the process chamber, and NF3 gas plasma is used to clean the inner wall of the process chamber.
[0007] The residue from the cleaning process is purged using a first inert gas, and the residue is then extracted from the process chamber.
[0008] A precursor gas is introduced into the process chamber for pretreatment to form a silicon-rich protective layer on the inner wall of the process chamber.
[0009] The high-frequency radio frequency applied to the process chamber is adjusted to ionize the residual precursor gas and the reaction byproducts generated during the pretreatment process to obtain residual plasma. At the same time, the low-frequency radio frequency applied to the process chamber is adjusted so that the residual plasma gains a certain amount of energy in the magnetic field and thus suspends in the magnetic field of the process chamber.
[0010] The residual plasma is purged using a second inert gas and then extracted from the process chamber.
[0011] Optionally, in the cleaning method of the process chamber, during the pretreatment operation of introducing precursor gas into the process chamber, the precursor gas is OMCTS gas.
[0012] Optionally, in the cleaning method of the process chamber, the reaction byproducts generated during the pretreatment operation of introducing OMCTS gas into the process chamber are organic carbon silicon compounds.
[0013] Optionally, in the cleaning method of the process chamber, the high-frequency radio frequency applied to the process chamber is adjusted to ionize the residual precursor gas and the reaction byproducts generated during the pretreatment operation to obtain silicon ions, hydrogen ions, carbon ions and oxygen ions.
[0014] Optionally, in the cleaning method of the process chamber, the high-frequency radio frequency is 100W during the process of adjusting the high-frequency radio frequency applied to the process chamber to ionize the residual precursor gas and the reaction byproducts generated during the pretreatment operation to obtain residual plasma.
[0015] Optionally, in the cleaning method of the process chamber, during the process of adjusting the low-frequency radio frequency applied to the process chamber to suspend the residual plasma in the magnetic field of the process chamber, the low-frequency radio frequency is 0W.
[0016] Optionally, in the cleaning method of the process chamber, the low-frequency radio frequency is close to the cyclotron frequency of the residual plasma.
[0017] Optionally, in the cleaning method of the process chamber, while adjusting the high-frequency radio frequency applied to the process chamber to ionize the residual precursor gas and the reaction byproducts generated during the pretreatment operation to obtain residual plasma, and simultaneously adjusting the low-frequency radio frequency applied to the process chamber to suspend the residual plasma in the magnetic field of the process chamber, the pressure of the process chamber is 5 Torr, the process temperature is 350°C, and the process duration is 5 seconds.
[0018] Optionally, in the cleaning method of the process chamber, during the cleaning process using NF3 gas, the pressure of the process chamber is 6 Torr, the process temperature is 350°C, and the process duration is 3 seconds.
[0019] Optionally, in the cleaning method of the process chamber, the first inert gas is argon; the second inert gas is helium.
[0020] The technical solution of this application has at least the following advantages:
[0021] In the cleaning method of the process chamber provided in this application, after a precursor gas is introduced into the process chamber for pretreatment to form a silicon-rich protective layer on the inner wall of the process chamber, the residual precursor gas and reaction byproducts generated during the pretreatment process are ionized by adjusting the high-frequency and low-frequency radio frequency applied to the process chamber. The resulting residual plasma is suspended in the process chamber, which facilitates the subsequent purging and extraction of the process chamber using a second inert gas. This prevents the presence of residual precursor gas and reaction byproducts throughout the cleaning process, avoids the formation of embedded impurity particles in the wafer edge area due to residual precursor gas and reaction byproducts, improves the reliability of the CVD preparation process in the process chamber, and increases the wafer yield. Attached Figure Description
[0022] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0023] Figure 1 This is a flowchart of a cleaning method for a process chamber according to an embodiment of the present invention. Detailed Implementation
[0024] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0025] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0026] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0027] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.
[0028] This application provides a method for cleaning a process chamber, referring to... Figure 1 , Figure 1 This is a flowchart of a cleaning method for a process chamber according to an embodiment of the present invention. The cleaning method for the process chamber includes:
[0029] First, step S1 is performed: NF3 gas is introduced into the process chamber, and NF3 gas plasma is used to clean the inner wall of the process chamber.
[0030] Then, step S2 is performed: the residue from the cleaning process is purged using a first inert gas and the residue is extracted from the process chamber.
[0031] Specifically, during the cleaning process using NF3 gas, the pressure in the process chamber is 6 Torr, the process temperature is 350°C, and the process duration is 3 seconds.
[0032] In this embodiment, the first inert gas is argon.
[0033] Next, step S3 is performed: a precursor gas is introduced into the process chamber for pretreatment to form a silicon-rich protective layer (SiCO) on the inner wall of the process chamber.
[0034] In this embodiment, during the pretreatment process of introducing precursor gas into the process chamber, the precursor gas is OMCTS gas. Through adsorption or slight reaction of OMCTS gas, active sites (such as hydroxyl groups) on the inner wall surface of the process chamber are neutralized, forming a silicon-rich protective layer on the inner wall of the process chamber. This prevents the low dielectric constant film from developing defects (such as high dielectric constant or collapsed pore structure) due to residual moisture or impurities on the inner wall of the process chamber falling onto the wafer (low dielectric constant film) on the worktable during the subsequent formal fabrication of the low dielectric constant film using the process chamber.
[0035] Further, step S4 is performed: the high-frequency radio frequency applied to the process chamber is adjusted to ionize the residual precursor gas and the reaction byproducts generated during the pretreatment operation to obtain residual plasma. At the same time, the low-frequency radio frequency applied to the process chamber is adjusted so that the residual plasma gains a certain amount of energy in the magnetic field and is thus suspended in the magnetic field of the process chamber. The pressure of the process chamber is 5 Torr, the process temperature is 350°C, and the process duration is 5 seconds.
[0036] During the pretreatment process of introducing OMCTS gas into the process chamber, the reaction byproducts generated are organic carbon silicon compounds.
[0037] Because of the residual OMCTS gas and carbon-silicon organic matter, the high-frequency radio frequency applied to the process chamber is adjusted to ionize the residual precursor gas and the reaction byproducts generated during the pretreatment operation, thereby obtaining silicon ions, hydrogen ions, carbon ions and oxygen ions.
[0038] Preferably, the high-frequency radio frequency is 100W.
[0039] Preferably, the low-frequency band radio frequency is 0W.
[0040] During the process of suspending residual plasma (ions), the high-frequency band can ionize the residual precursor gas and reaction byproducts generated during the pretreatment operation into residual plasma. In addition, the adjustment of the high-frequency band can affect the plasma generation efficiency, density and overall activity. Different high-frequency power and frequency settings will cause changes in parameters such as electron temperature and ion density in the plasma, thereby affecting the generation and initial energy state of ions. The adjustment of the low-frequency band mainly acts on the movement and confinement of ions. By changing the frequency and amplitude of the low-frequency bias voltage, the force on the ions in the electric field can be adjusted, so that they form a specific movement trajectory in the process chamber, thereby achieving ion suspension.
[0041] The low-frequency radio frequency is close to the cyclotron frequency of the residual plasma.
[0042] Finally, step S5 is performed: the residual plasma is purged with a second inert gas and extracted from the process chamber.
[0043] In this embodiment, the second inert gas is helium.
[0044] In this application, after a precursor gas is introduced into the process chamber for pretreatment to form a silicon-rich protective layer on the inner wall of the process chamber, the residual precursor gas and reaction byproducts generated during the pretreatment process are ionized by adjusting the high-frequency and low-frequency radio frequency applied to the process chamber. The resulting residual plasma is suspended in the process chamber, which facilitates subsequent purging and extraction of the process chamber using a second inert gas. This prevents the presence of residual precursor gas and reaction byproducts during the cleaning stage, avoiding contamination of the wafer edge area by residual precursor gas and reaction byproducts, thus forming embedded impurity particles. This improves the reliability of the CVD fabrication process in the process chamber and increases the wafer yield.
[0045] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.
Claims
1. A method for cleaning a process chamber, characterized in that, include: NF3 gas is introduced into the process chamber, and NF3 gas plasma is used to clean the inner wall of the process chamber. The residue from the cleaning process is purged using a first inert gas, and the residue is then extracted from the process chamber. A precursor gas is introduced into the process chamber for pretreatment to form a silicon-rich protective layer on the inner wall of the process chamber. The high-frequency radio frequency applied to the process chamber is adjusted to ionize the residual precursor gas and the reaction byproducts generated during the pretreatment process to obtain residual plasma. At the same time, the low-frequency radio frequency applied to the process chamber is adjusted so that the residual plasma gains a certain amount of energy in the magnetic field and thus suspends in the magnetic field of the process chamber. The residual plasma is purged using a second inert gas and then extracted from the process chamber.
2. The cleaning method for the process chamber according to claim 1, characterized in that, During the pretreatment process of introducing precursor gas into the process chamber, the precursor gas is OMCTS gas.
3. The cleaning method for the process chamber according to claim 2, characterized in that, During the pretreatment process of introducing OMCTS gas into the process chamber, the reaction byproducts are organic carbon silicon compounds.
4. The cleaning method for the process chamber according to claim 3, characterized in that, The high-frequency radio frequency applied to the process chamber is adjusted to ionize the residual precursor gas and the reaction byproducts generated during the pretreatment process to obtain silicon ions, hydrogen ions, carbon ions and oxygen ions.
5. The cleaning method for the process chamber according to claim 1, characterized in that, In the process of adjusting the high-frequency radio frequency applied to the process chamber to ionize the residual precursor gas and the reaction byproducts generated during the pretreatment operation to obtain residual plasma, the high-frequency radio frequency is 100W.
6. The cleaning method for the process chamber according to claim 1, characterized in that, During the process of adjusting the low-frequency radio frequency applied to the process chamber to suspend the residual plasma in the magnetic field of the process chamber, the low-frequency radio frequency is 0W.
7. The cleaning method for the process chamber according to claim 1, characterized in that, The low-frequency radio frequency is close to the cyclotron frequency of the residual plasma.
8. The cleaning method for the process chamber according to claim 1, characterized in that, During the process of adjusting the high-frequency radio frequency applied to the process chamber to ionize the residual precursor gas and the reaction byproducts generated during the pretreatment operation to obtain residual plasma, and simultaneously adjusting the low-frequency radio frequency applied to the process chamber to suspend the residual plasma in the magnetic field of the process chamber, the pressure of the process chamber is 5 Torr, the process temperature is 350°C, and the process duration is 5 seconds.
9. The cleaning method for the process chamber according to claim 1, characterized in that, During the cleaning process using NF3 gas, the pressure in the process chamber is 6 Torr, the process temperature is 350°C, and the process duration is 3 seconds.
10. The cleaning method for the process chamber according to claim 1, characterized in that, The first inert gas is argon; the second inert gas is helium.