A semiconductor etching apparatus and a method for on-line cleaning of particles

Abstract

The application discloses a kind of semiconductor etching equipment and particle on-line cleaning method, applied to semiconductor manufacturing equipment technical field, wherein equipment includes at least one process cavity module, at least one auxiliary processing module and central transmission robot;Auxiliary processing module is equipped with upper and lower electrode plate and is made of electret material Simulation wafer, can be charged or discharged by applying high voltage electricity to it;When needing to clean process cavity particle, charged simulation wafer is transmitted to process cavity, and particle is adsorbed by using electrostatic force and then transmitted back to auxiliary cavity to discharge, and finally auxiliary cavity can be cleaned.The application initiates "transfer type" on-line cleaning concept, can efficiently remove particle pollutants without damaging process cavity vacuum and process state, completely avoids the need for vacuum breaking and aging process of traditional mode, significantly improves equipment utilization and production yield, and realizes the breakthrough of semiconductor etching equipment maintenance technology.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor manufacturing equipment, in particular to a semiconductor device for plasma etching process, and an on-line cleaning method of particle contamination realized on the device without destroying the vacuum state of the process chamber. BACKGROUND

[0002] In the process of integrated circuit manufacturing, plasma etching is a key process. In processes such as deep silicon etching and dielectric etching, process gas generates plasma under the action of radio frequency energy, and physical and chemical reactions occur on the wafer surface, thereby etching the required pattern. A large amount of by-products are produced in this process, some of which exist in the form of polymers and are deposited on the surfaces of components such as the inner wall, electrode, and focusing ring of the process chamber. These deposits are easily peeled off and form particles under the action of plasma impact or thermal stress in subsequent processes. Once these particles fall on the wafer surface, they will cause pattern defects, leading to device short circuit, open circuit, or performance degradation, and seriously reduce product yield.

[0003] Currently, the main method to solve the particle problem is to perform periodic preventive maintenance (PM). That is, to stop production, expose the process chamber to the atmosphere (break the vacuum), and manually clean by engineers. This method has significant disadvantages: 1) low equipment utilization: the equipment cannot produce during maintenance, and long-term chamber aging is required after maintenance to stabilize the chamber environment, further extending the downtime; 2) introducing new pollution risk: the break vacuum process may introduce new environmental contaminants; 3) poor consistency: the effect of manual cleaning is difficult to guarantee absolute consistency, which may affect process stability.

[0004] Therefore, the industry urgently needs a device and method that can automatically clean particles on-line without interrupting production and destroying the vacuum environment of the process chamber. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art and provide a semiconductor etching device and an on-line cleaning method of particle contamination, to realize the on-line, automatic, and vacuum environment cleaning of particles, significantly improving equipment utilization and production yield.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] The application provides a semiconductor etching device, which is characterized in that a dedicated auxiliary processing module (i.e. an auxiliary cavity) and an analog wafer made of electret material are integrated. The device comprises at least one process cavity module, at least one auxiliary processing module and a central transfer robot. The auxiliary processing module is provided with upper and lower electrode plates and an analog wafer made of electret material (e.g. PTFE / quartz composite material). The analog wafer can be charged into an "electrostatic dust collector" by applying voltage to the electrode plates through a high-voltage power supply. The central transfer robot is arranged between the process cavity module and the auxiliary processing module and is used for transferring wafers and dedicated processing tools in a vacuum environment. The charged analog wafer can be transferred into the process cavity module which needs to be cleaned, so as to adsorb the particles floating and adhering in the cavity by means of the electrostatic field. After the adsorption is completed, the robot sends the analog wafer back to the auxiliary processing module for discharging. Finally, the particles can be easily removed by opening the auxiliary processing module, and the main process cavity always maintains a vacuum and process-ready state.

[0008] Preferably, the analog wafer comprises:

[0009] a rigid substrate layer made of high-purity dielectric material; and

[0010] a surface functional layer coated on at least one surface of the rigid substrate layer and made of polymer material with high charge retention capacity.

[0011] Preferably, the rigid substrate layer is quartz, alumina ceramic or aluminum nitride ceramic; and the surface functional layer is polytetrafluoroethylene, fluorinated ethylene-propylene copolymer or polyvinylidene fluoride.

[0012] Preferably, the total thickness of the analog wafer is 1mm to 5mm.

[0013] Preferably, the auxiliary processing module further comprises a plurality of insulating support pins made of ultra-high resistivity insulating material and arranged in the lower electrode plate in a liftable manner, which are used for supporting and lifting the analog wafer during the transfer process.

[0014] Preferably, the end effector of the central transfer robot is a reversible double-sided structure, which comprises a first working surface coated with an anti-static coating and used for transferring semiconductor wafers, and a second working surface with high surface resistivity and used for transferring the analog wafer.

[0015] Preferably, the semiconductor etching device further comprises:

[0016] a particle monitoring system used for monitoring the particle concentration in the process cavity module in real time or periodically.

[0017] A control system connected with the particle monitoring system, the central transfer robot and the high-voltage power supply, configured to automatically start a cleaning program when the particle concentration is monitored to exceed a preset threshold, control the high-voltage power supply to charge the dummy wafer, and dispatch the central transfer robot to complete the transfer operation of the dummy wafer.

[0018] Preferably, the high-voltage power supply can output DC or pulsed voltage, and the voltage range is positive and negative 2kV to positive and negative 20kV.

[0019] The present application provides a particle online cleaning method using the device described in any one of the examples in the present application. The method comprises:

[0020] A dummy wafer preparation step: in the auxiliary processing module, the dummy wafer is charged by applying voltage to the upper and lower electrode plates;

[0021] A particle adsorption step: the charged dummy wafer is transferred to the target process cavity module by the central transfer robot, and is placed for a predetermined time to adsorb particles on the inner wall and component surface of the cavity by electrostatic force;

[0022] A dummy wafer recycling step: the dummy wafer with adsorbed particles is transferred back to the auxiliary processing module;

[0023] A charge release step: the dummy wafer is discharged in the auxiliary processing module.

[0024] The dummy wafer is charged in the auxiliary module, then the charged dummy wafer is transferred to the process cavity for particle adsorption, and finally the dummy wafer is recycled and discharged. The whole process is automatic and online, and the process cavity always maintains vacuum.

[0025] Preferably, when the dummy wafer is charged, the upper electrode plate and the lower electrode plate are applied with voltage of opposite polarity;

[0026] Preferably, the predetermined time is 30 seconds to 300 seconds.

[0027] Preferably, the discharge treatment is realized by applying voltage of opposite polarity to the upper electrode plate and the lower electrode plate when charging, or by grounding device to discharge the dummy wafer.

[0028] Preferably, in the particle adsorption step, the dummy wafer is placed on the electrostatic chuck of the process cavity module, and a bias voltage is applied to the electrostatic chuck, the polarity of the bias voltage being the same as the polarity of the charge carried by the dummy wafer, so as to enhance the adsorption force of the particles with opposite charge.

[0029] Preferably, the method is performed under the condition that the process cavity module maintains vacuum and process temperature.

[0030] Preferably, in any one of the methods of the present invention, the particulate matter is a polymer by-product of plasma etching process;

[0031] And / or, perform particulate cleaning processes between batch wafer processing;

[0032] The method further includes one or more of the following steps:

[0033] Particulate matter monitoring steps: Monitor the particulate matter level in the process chamber module in real time or periodically, and initiate the online cleaning process when the particulate matter level exceeds the predetermined standard;

[0034] Auxiliary processing module cleaning steps: Open the auxiliary processing module and physically remove the particulate matter deposited on the surface of the simulated wafer or the inner surface of the auxiliary processing module cavity.

[0035] Compared with the prior art, the present invention has one or more of the following advantages:

[0036] On the one hand, it enables online cleaning without breaking the vacuum: it completely avoids the long aging wait caused by breaking the vacuum, shortens the traditional maintenance process that takes several hours to less than ten minutes, and significantly improves the equipment utilization rate, for example, by at least 20%.

[0037] Secondly, automation and intelligence are achieved: the cleaning process can perform predictive maintenance fully automatically, reducing human intervention and improving process consistency;

[0038] In three aspects, it has a good cleaning effect: it uses electrostatic adsorption to have a good adsorption effect on positively charged, negatively charged and neutral particles, and is especially good at removing light polymer particles.

[0039] In four aspects, it has strong compatibility: the solution can be integrated into existing etching equipment as an add-on module, with low modification costs and easy promotion and application. Attached Figure Description

[0040] Figure 1 This is a top view of the overall layout of the semiconductor etching equipment in an embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of the vertical cross-sectional structure of the process cavity module in an embodiment of the present invention;

[0042] Figure 3 This is a schematic diagram of the vertical cross-sectional structure of the auxiliary processing module in an embodiment of the present invention;

[0043] Figure 4 This is a schematic diagram of electrostatic adsorption within the process cavity in an embodiment of the present invention;

[0044] Figure 5This is a schematic diagram of the automatic cleaning process in an embodiment of the present invention. Detailed Implementation

[0045] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0046] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0047] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this invention, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0048] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0049] Additionally, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that practice can be carried out without these specific details.

[0050] Currently, the process chamber is a vacuum chamber. After the chamber is opened (i.e., the vacuum is broken), it needs to be re-aged before it can be reused in the processing process. Therefore, in daily work, it is generally necessary to minimize the frequency of opening the chamber to avoid excessive downtime affecting production capacity.

[0051] In addition, since the process cavity is used for wafer processing, various process gases are required for the reaction. The by-product particles generated during the reaction inevitably accumulate on the inner wall of the cavity, the surface of the cavity components, etc. Therefore, these particles need to be cleaned, otherwise these particles can easily contaminate the wafer.

[0052] Long-term efforts by those skilled in the art have focused on improving cleaning efficiency or shortening aging time under the overarching premise of "breaking the vacuum," such as developing more efficient cleaning tools or optimizing aging formulas. However, these improvements have not escaped the constraints of the technical framework that "production must be interrupted and the vacuum must be broken."

[0053] Therefore, the industry has long faced a problem that has not been effectively solved: how to achieve effective online cleaning of particulate contaminants without disrupting the vacuum state of the process chamber.

[0054] The present invention recognizes that solving the aforementioned long-standing technical problems requires a completely new technical concept that fundamentally overturns the traditional periodic preventive maintenance (PM) work model, that is, it is necessary to completely break away from the traditional mindset of "cleaning directly in the process chamber".

[0055] In response, this invention fundamentally rethinks the approach: the target of cleaning is the particulate matter itself, not the chamber itself. Therefore, if the particulate matter can be "transferred" from the process chamber to a container that can be opened independently at any time without affecting the main process environment, all problems will be solved.

[0056] Based on this reverse thinking, the core technical concept of this invention emerged: constructing a "transfer-based" online cleaning system. Its core idea is:

[0057] On the one hand, create a dedicated "contaminant receiver": design a carrier (such as a simulated wafer) with strong adsorption capacity that can enter the process chamber and actively capture particulate matter in the chamber.

[0058] Secondly, construct an independent "pollutant treatment station": design an independent auxiliary cavity (such as an auxiliary treatment cleaning module) specifically for "charging" (giving adsorption capacity) and "discharging" (releasing adsorbed pollutants) the aforementioned carriers.

[0059] In three aspects, a seamless "pollutant transfer channel" is established: utilizing the existing vacuum transfer robot of the equipment, the carrier is automatically transferred between the "process chamber" (adsorption point) and the "auxiliary treatment station" (charging / discharging point) in a vacuum environment.

[0060] By performing a closed-loop operation through the above three steps, particulate matter removal can be completed without disrupting the vacuum and production status of the process chamber.

[0061] Based on the above technical concept, the present invention provides the following implementation:

[0062] First, regarding the implementation of the "pollutant receiver": select a material that can maintain its charge for a long time and design the corresponding structure.

[0063] In terms of material selection, this invention creatively uses electret materials (such as PTFE) as the core functional material for simulating wafers. Once the electret is charged, its electrostatic field decays extremely slowly, ensuring stable adsorption force for a sufficient operating time.

[0064] In terms of structural design, to ensure its mechanical stability and durability in a vacuum radio frequency environment, this invention can adopt a composite structure design, in which high-purity quartz or ceramic is used to provide rigid support, and the surface is covered with a PTFE film as a functional layer. This not only solves the problem of insufficient rigidity of pure PTFE, but also makes it physically compatible with real wafers, facilitating transmission.

[0065] Secondly, regarding the implementation of the "pollutant treatment station": an auxiliary chamber is set up for charging and discharging purposes.

[0066] In terms of the function of the auxiliary cavity, upper and lower electrode plates are set in the auxiliary cavity and connected to a high-voltage power supply. By applying a DC voltage of several thousand volts, the electret simulated wafer can be efficiently charged in the strong electric field between the two electrode plates, while applying a voltage in the opposite direction can achieve efficient discharge.

[0067] The auxiliary chamber is a separate module, isolated from the process chamber by a vacuum valve. Its body can be cleaned independently by breaking the vacuum, without affecting the vacuum environment of the main process chamber.

[0068] Third, regarding the implementation of the "pollutant transfer channel": the existing central transmission robot in the system is equipped with a flip-up, double-sided end effector.

[0069] The existing central transfer robot in the system is used to transfer the carrier. The robot's end fingers that contact the wafer are made of high-resistivity insulating material and can be flipped. The front side is coated with an anti-static coating for transferring the wafer, while the back side is in a high-resistivity state and is specifically for transferring charged simulated wafers to prevent charge leakage and ensure that the transfer process does not affect the adsorption capacity.

[0070] In summary, by integrating a particulate matter monitoring system and a central control system, the entire process of "monitoring-decision-charging-transmission-adsorption-recovery-discharge" is fully automated through system integration. The equipment can intelligently determine when cleaning is needed and automatically schedule the execution without human intervention, maximizing the value of the technological concept.

[0071] Therefore, based on the above technical concept, the present invention can bring about one or more of the following beneficial effects:

[0072] On the one hand, it can fundamentally solve the contradiction between vacuum breaking and machine shutdown: the process chamber does not need to break the vacuum or undergo aging, achieving true "zero" downtime maintenance and significantly improving equipment utilization;

[0073] Secondly, predictive intelligent maintenance has been achieved: by adding an automatic triggering mechanism for real-time particulate matter monitoring or a timed maintenance mechanism, the maintenance method has been changed from "regular preventive" which requires production stoppage to "on-demand predictive", making it more accurate and efficient.

[0074] In three aspects, it improves process consistency: it avoids process fluctuations caused by manual maintenance and drastic changes in chamber conditions, resulting in more stable product yield.

[0075] In four aspects, it has good compatibility and scalability: the modular design of the solution allows it to be integrated as an efficient add-on system into a variety of existing plasma etching equipment.

[0076] In summary, this invention is not a simple improvement on existing technologies, but a complete technical system built on a novel "transfer-based cleaning" technical concept. It has been fully and effectively implemented through a series of specific and synergistic technical means, successfully solving the core technical problem that has long plagued the industry.

[0077] The following examples illustrate each implementation instance.

[0078] Example 1: Semiconductor Etching Equipment

[0079] refer to Figure 1 This invention provides a semiconductor etching apparatus, comprising four process chamber modules (A, B, C, D), two auxiliary processing modules (E, F), and a wafer loading port (I, J). A central transfer robot is located in the transfer chamber at the center of the apparatus (not shown in the figure). All chambers are separated by vacuum valves, which can be opened or closed; the robot can transfer wafers or simulated wafers to any module in a vacuum environment.

[0080] refer to Figure 2The diagram illustrates a process chamber module used for wafer etching processes or in-line particulate cleaning. This module includes a chamber cover 1, a wafer 2 (or a simulated wafer), a focusing ring 3, an electrostatic chuck 4, an inner liner ring 5, an RF isolation ring 6, a gas extraction and equalization ring 7, and a chamber body 8, as well as an RF feed system (not shown). The focusing ring 3 is generally made of the same material as the wafer; the electrostatic chuck (ESC) 4 has an aluminum body with a ceramic upper surface for holding and fixing the wafer; the focusing ring 3 surrounds the electrostatic chuck 4; the inner liner ring 5 is made of a high-dielectric material, a non-metallic material (such as quartz); the RF isolation ring 6 is a non-metallic material, typically ceramic; and the RF feed system provides RF energy to the chamber to excite plasma. For example, in an ICP etching apparatus, the RF feed system feeds RF power through the electrostatic chuck 4, which acts as a substrate to excite process gases to form plasma for etching.

[0081] refer to Figure 3 The diagram illustrates that the auxiliary cavity module serves as the aforementioned "contaminant treatment station." 'a' represents the cavity, 'b' is the upper electrode support (an insulator), 'c' is the upper electrode, 'd' is the simulated wafer, made of electret material (such as permanent magnets), for example, with high-purity quartz internally for rigidity and PTFE externally, approximately 1-3 mm thick, 'e' is the lower electrode, 'f' is the lower electrode support (an insulator), and 'g' is the support pin for supporting the simulated wafer 'd, preferably an ultra-high resistance insulator. When the upper and lower electrodes are energized, the simulated wafer 'd' can be charged; when a reverse voltage is applied, it can be discharged. In the preferred example, the voltage is typically several kilovolts to tens of kilovolts, but in practice, it can be determined based on the actual charging and discharging needs of the simulated wafer.

[0082] refer to Figure 4 The illustration shows that when there are many by-product particles (such as positively charged particles, neutral particles, etc.) in the process chamber after the process is processed, such as when the particles are detected to be excessive in real time or periodically, the robot in the equipment will transfer the charged simulated wafer d in the auxiliary chamber into the process chamber. Due to electrostatic adsorption, the particles in the process chamber will be adsorbed on the surface of the simulated wafer. Then the robot will transfer the simulated wafer into the auxiliary chamber, where the simulated wafer will be discharged.

[0083] In some examples, the enhanced adsorption process is as follows: During the adsorption step, a bias voltage (V_bias) is applied to the electrostatic chuck 4 of the process chamber, with the same polarity as the charge on the simulated wafer d (e.g., if the simulated wafer is negatively charged, V_bias is also set to a negative voltage, such as -500V). According to the principle of electrostatics, like charges repel each other. This creates a stronger repulsive electric field pointing towards the top of the chamber in the space above the simulated wafer d. This enhanced electric field can more effectively drive positively charged particles toward the surface of the simulated wafer d and generate a stronger polarization force on neutral particles, thereby significantly improving the adsorption efficiency and range.

[0084] In addition, the robot used to transport wafers (or simulated wafers) has high-resistivity insulating fingers at the end that contact the wafer. These fingers are also flip-flops with an anti-static coating on the front for transporting wafers and a high-resistivity coating on the back for transporting simulated wafers.

[0085] Example 2: Simulated wafer with composite structure

[0086] The analog wafer d is a carefully designed composite structure whose core lies in resolving the contradiction between "charge retention capability" and "mechanical stability".

[0087] Rigid substrate: Typically made of high-purity, high-resistivity dielectric materials, such as fused silica (SiO2), alumina (Al2O3), or aluminum nitride (AlN) ceramics. Its primary function is to provide sufficient mechanical strength and rigidity to prevent deformation or breakage during robotic transport in a vacuum environment, placement on an electrostatic chuck, and temperature changes. In practice, the thickness can range from 1 mm to 3 mm.

[0088] Surface functional layer: This layer is coated on at least one (preferably two) main surfaces of the rigid substrate. It is made of an electret material with excellent charge trapping properties, such as polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), fluorinated ethylene propylene copolymer (FEP), or polyvinylidene fluoride (PVDF). After being charged via corona charging or contact charging, this layer can form a durable and stable electrostatic field. In practice, its thickness can be between 0.1 mm and 1 mm.

[0089] The simulated wafer d can be made by bonding a PTFE film to both sides of a pretreated quartz substrate using a high-temperature hot-pressing process. Alternatively, the simulated wafer d can be made by forming a dense fluoropolymer coating on the quartz substrate through methods such as spraying, spin coating, or sintering.

[0090] By comparing the charge decay characteristics of pure quartz wafers and the composite structure simulated wafers (quartz + PTFE) of this invention, in an environment of 25°C and 50% relative humidity, after initial charging to -5kV, the surface potential of pure quartz wafers decays by more than 80% within 1 hour, while the surface potential of the simulated wafers in this invention can still maintain more than 85% of the initial value after 24 hours. This shows that the composite structure can greatly improve the charge retention capability and ensure that the simulated wafers always have strong particulate matter adsorption capacity throughout the entire "transfer-adsorption-recovery" cycle.

[0091] In some examples, the surface functional layer of the simulated wafer d may not be a uniform coating, but rather patterned into a grid, lattice, or other geometric shape to adjust the surface electric field distribution and achieve a more uniform or specific area adsorption effect.

[0092] In some examples, a metal mesh can be embedded inside the rigid substrate layer of the simulated wafer d. This mesh can be biased during charging to actively control the electric field strength and distribution on the surface of the simulated wafer, thereby enabling programmable adjustment of the adsorption force.

[0093] Example 3: High-voltage charging and discharging of the auxiliary processing module

[0094] In the auxiliary processing module, support pins g are used to achieve precise positioning and electrical isolation of the simulated wafer d. In real time, the support pins g are made of an insulating material with ultra-high resistivity (such as alumina ceramic). The extremely high resistance of the support pins g ensures that the discharge process is controlled and slow, avoiding sparks or damage to the simulated wafer that may be caused by instantaneous discharge.

[0095] The auxiliary processing module's workflow is as follows: When the robotic arm feeds the simulated wafer d into the auxiliary cavity, the support pin g rises from the lower electrode plate e, supporting the simulated wafer d and disengaging it from the upper substrate c and lower electrode plate e to prevent short circuits. During charging or discharging operations, the support pin g descends, allowing the simulated wafer d to be stably placed on the lower electrode plate e, ensuring good electrical contact.

[0096] High-voltage charging strategy: The high-voltage power supply can output DC, pulsed DC, or AC-DC superimposed waveforms, with a voltage range of ±2kV to ±20kV. During charging, high voltages of opposite polarity and equal absolute value (e.g., +8kV and -8kV) are applied to the upper plate c and the lower plate e, creating a strong electric field between them. This causes the simulated wafer d to become polarized in this electric field and be injected with charge.

[0097] In some examples, pulse charging can be used, employing pulsed voltage (e.g., pulse width 1ms, interval 1ms) for charging, which can effectively suppress dielectric breakdown, allow the use of higher peak voltages, thereby injecting more charge in a shorter time and improving charging efficiency.

[0098] Discharge can be performed in any of the following ways or in combination:

[0099] For example, the reverse voltage method: applying a voltage with the opposite polarity to that used during charging "pulls" the injected charge out.

[0100] For example, the grounding discharge method: the upper and lower plates (or one of them) are grounded, and the charge is guided to discharge to the ground by slightly touching the surface of the simulated wafer d through a movable grounding probe (not shown in the figure).

[0101] For example, a redundant discharge strategy of "primarily reverse voltage discharge and secondarily ground probe discharge" can be adopted. First, the main charge is neutralized with reverse voltage, then the support pin g is raised, driving a ground metal probe (or metal brush) to gently sweep across the simulated wafer surface to eliminate any possible residual local charge, ensuring the safety of the cleaning operator and the consistency of the simulated wafer's next charge.

[0102] Example 4: Double-sided design of robot end effector

[0103] The end effector (manipulator) of the central transfer robot can adopt a flip-up "double-sided heterogeneous" design:

[0104] First working surface (front): Used for transporting expensive product wafers (also known as process wafers). In practice, the surface may be coated with an antistatic coating, resulting in extremely high surface resistance, such as 10 Ω·cm. 6 Ω or higher, the extremely high resistance is sufficient to smoothly discharge the static charge generated during the transmission process, preventing the charge accumulation from damaging the circuit, while at the same time not dissipating the bias voltage on the electrostatic chuck of the process cavity too quickly.

[0105] The second working surface (reverse side): specifically designed for transmitting charged analog wafer d, its surface is made of intrinsically high insulating materials (such as PEEK, ceramic coating), with extremely high surface resistivity, for example, greater than 10. 10 Ω. When the robotic arm contacts the charged simulated wafer d with this surface, it forms an effective insulating barrier, which greatly slows down the rate at which the charge on the simulated wafer leaks to the robotic arm body (usually grounded), ensuring the adsorption efficiency.

[0106] By solving two completely different transmission needs with a robotic arm in the same device, "one machine for two purposes" is achieved, avoiding the high cost of configuring an additional dedicated robot for transmitting analog wafers, demonstrating excellent design ingenuity and economy.

[0107] Example 5: Closed-loop control process for automated cleaning

[0108] This embodiment provides an automated cleanup process that implements a complete "perception-decision-execution" closed-loop control.

[0109] refer to Figure 5 The automated cleanup process for closed-loop control is illustrated below:

[0110] Sensing (S501): After each wafer is processed, the particulate matter sensor (such as a light scattering particle counter) samples and monitors the process cavity, that is, monitors the particulate matter in the process cavity.

[0111] Decision (S502): The control system compares the particulate matter concentration data monitored in step S501 with a preset threshold (which can be set based on different process formulations) to determine whether the particulate matter exceeds the standard. If it exceeds the standard, steps S504-S507 are initiated to implement the online cleaning process; if it does not exceed the standard, normal production continues (S503).

[0112] Execution (S504-S507): The control system automatically executes a series of instructions for the online cleaning process in sequence. For example, step S504 schedules the auxiliary cavity to prepare the simulated wafer (i.e., completes the charging of the simulated wafer in the auxiliary cavity) -> step S505 schedules the robot to transfer the simulated wafer from the auxiliary cavity to the process cavity and place the simulated wafer on the electrostatic chuck of the process cavity. If a bias voltage needs to be applied, the electrostatic chuck of the process cavity can also be controlled to be in a biased state (e.g., to provide a bias electric field for the simulated wafer through a bias voltage, if the adsorption process requires bias to increase the adsorption effect). The simulated wafer adsorbs the particles in the process cavity (in practice, the adsorption process can be judged by timing, monitoring particles, etc. to determine whether the adsorption process has been completed) -> step S506 schedules the robot to recover the simulated wafer, that is, the robot transfers the simulated wafer that has completed adsorption from the process cavity back to the auxiliary cavity -> and step S507 schedules the auxiliary cavity to discharge the simulated wafer, etc.

[0113] In addition, during the cleaning process, the system can also prompt the operator to manually clean the auxiliary cavity (S508) through the human-machine interface. At this time, the process cavity continues to be put into the production of the next wafer. The cleaning of the auxiliary cavity and the normal production of the process cavity do not affect each other, thus ensuring the production efficiency of the process cavity.

[0114] Based on the closed-loop control described above, a cleaning process that requires manual intervention can be optimized into a fully automated intelligent solution, realizing predictive maintenance (PdM) and truly improving equipment efficiency.

[0115] Example 6: General Flowchart of Particulate Matter Cleaning Method

[0116] This method is a natural extension and specification of the aforementioned equipment functions. Its process is similar to the control logic of Embodiment 5. It is an operation process that is executed sequentially in a vacuum environment. The process will not be described in detail here, but its vacuum continuity will be emphasized.

[0117] Throughout the entire process, from monitoring to recovery, the vacuum environment of the process chamber module was never disrupted. Its pressure was consistently maintained at the process background vacuum level (e.g., 10). -5 (At the Pa level), thus maintaining stable key environmental parameters such as the surface condition of the chamber's inner wall and the partial pressure of residual gas. Therefore, after cleaning, the chamber can directly run the processing of the next wafer without any aging treatment, achieving a fundamental shift from "downtime maintenance" to "online care."

[0118] In some examples, during electrostatic adsorption, the settling time is 30 to 300 seconds, which can effectively adsorb particulate matter in the process chamber without taking up too much production time in the process chamber.

[0119] In some examples, during the particulate matter adsorption step, a simulated wafer is placed on an electrostatic chuck of the process chamber module, and a bias voltage is applied to the electrostatic chuck with the same polarity as the charge on the simulated wafer to enhance the adsorption force on particles with opposite charges.

[0120] In this specification, the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the descriptions of the embodiments described later are relatively simple, and relevant parts can be referred to the descriptions of the foregoing embodiments.

[0121] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A semiconductor etching apparatus, characterized in that, include: At least one process chamber module is used for plasma etching of wafers in a vacuum environment; At least one auxiliary processing module is connected to the process chamber module via a vacuum transmission channel; A central transfer robot is positioned between the process chamber module and the auxiliary processing module to transfer wafers in a vacuum environment. The auxiliary processing module includes: cavity; The upper electrode plate and the lower electrode plate are disposed in the cavity; The simulated wafer, made of electret material, is movably disposed between the upper electrode plate and the lower electrode plate; A high-voltage power supply, electrically connected to the upper and lower electrode plates, is used to apply voltage to the electrode plates to charge or discharge the simulated wafer. The central transfer robot can transfer the charged simulated wafer from the auxiliary processing module to the process chamber module to adsorb particulate contaminants in the process chamber module by electrostatic force, and after electrostatic adsorption, transfer the simulated wafer from the process chamber module to the auxiliary processing module.

2. The semiconductor etching apparatus according to claim 1, characterized in that, The simulated wafer includes: A rigid substrate layer made of high-purity dielectric material; and A surface functional layer, coated on at least one surface of the rigid substrate layer, is made of a polymer material with high charge retention capacity.

3. The semiconductor etching apparatus according to claim 2, characterized in that, The rigid substrate layer is made of quartz, alumina ceramic, or aluminum nitride ceramic; the surface functional layer is made of polytetrafluoroethylene, fluorinated ethylene propylene copolymer, or polyvinylidene fluoride. And / or, the total thickness of the simulated wafer is 1 mm to 5 mm.

4. The semiconductor etching apparatus according to claim 1, characterized in that, The auxiliary processing module also includes: Multiple insulating support pins, made of ultra-high resistivity insulating material, are vertically and vertically mounted in the lower electrode plate to support and lift the simulated wafer during transmission.

5. The semiconductor etching apparatus according to claim 1, characterized in that, The end effector of the central transfer robot has a flip-up, double-sided structure, including: The first working surface is coated with an antistatic coating for transporting semiconductor wafers; The second working surface has a high surface resistivity and is used to transfer the simulated wafer; And / or, the semiconductor etching apparatus further includes: A particulate matter monitoring system is used to monitor the particulate matter concentration within the process chamber module in real time or periodically. The control system, connected to the particulate matter monitoring system, the central transmission robot, and the high-voltage power supply, is configured to: automatically start the cleaning program when the particulate matter concentration exceeds a preset threshold, control the high-voltage power supply to charge the simulated wafer, and schedule the central transmission robot to complete the transmission operation of the simulated wafer. And / or, the high-voltage power supply can output DC or pulsed voltage, with a voltage range of ±2kV to ±20kV.

6. A method for online particulate matter cleaning using a semiconductor etching apparatus as described in any one of claims 1-5, characterized in that, include: Simulated wafer preparation steps: In the auxiliary processing module, the simulated wafer is charged by applying voltage to the upper and lower electrode plates; Particulate matter adsorption step: The charged simulated wafer is transferred to the target process cavity module by a central transfer robot, and left to stand for a predetermined time. The particulate matter on the inner wall of the cavity and the surface of the components is adsorbed by electrostatic force. Simulated wafer recycling steps: The simulated wafers containing adsorbed particulate matter are transferred back to the auxiliary processing module; Charge release step: The simulated wafer is subjected to discharge processing in the auxiliary processing module.

7. The method according to claim 6, characterized in that, When charging the simulated wafer, voltages of opposite polarity are applied to the upper and lower electrode plates; And / or, the predetermined settling time is 30 seconds to 300 seconds; And / or, the discharge process is achieved by applying a voltage of opposite polarity to that used during charging to the upper and lower electrode plates; or by contacting the simulated wafer with a grounding device to perform the discharge.

8. The method according to claim 6, characterized in that, In the particulate matter adsorption step, a simulated wafer is placed on the electrostatic chuck of the process chamber module, and a bias voltage is applied to the electrostatic chuck. The polarity of the bias voltage is the same as the polarity of the charge on the simulated wafer, so as to enhance the adsorption force on particles with opposite charges.

9. The method according to claim 6, characterized in that, The method is performed under conditions where the process chamber module maintains vacuum and process temperature.

10. The method according to claim 6, characterized in that, The particulate matter is a polymer byproduct of the plasma etching process. And / or, perform particulate cleaning processes between batch wafer processing; The method further includes one or more of the following steps: Particulate matter monitoring steps: Monitor the particulate matter level in the process chamber module in real time or periodically, and initiate the online cleaning process when the particulate matter level exceeds the predetermined standard; Auxiliary processing module cleaning steps: Open the auxiliary processing module and physically remove the particulate matter deposited on the surface of the simulated wafer or the inner surface of the auxiliary processing module cavity.

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