Apparatus and method for particle control in loadlock chamber through electrostatic pad control

Abstract

According to the particle control device in a load lock chamber using electrostatic pad control of the present invention, by including an electrostatic pad disposed in the load lock chamber to generate electrostatic force and a control unit that controls the movement of particles present in the load lock chamber by controlling the electrostatic force by adjusting the potential applied to the electrostatic pad, the movement, floating, attachment, detachment, and discharge of particles generated or introduced in the load lock chamber can be precisely controlled by actively controlling the electrostatic force.

Description

Technology Field

[0001] The present invention relates to a particle control device and method in a load lock chamber using electrostatic pad control, and more specifically, to a particle control device and method that maintains the cleanliness inside the chamber by controlling an electrostatic pad in a vacuum environment of semiconductor manufacturing equipment to manage the generation, suspension, capture, and exhaust of particles. Background Technology

[0003] In conventional semiconductor equipment, methods for collecting particles using electrostatic force in an atmospheric (ATM) environment, such as the Equipment Front End Module (EFEM) area, have been primarily used. Additionally, some technologies have proposed methods to suppress particle scattering by installing a simple grating-type plate inside the load lock chamber or by applying a certain voltage to weaken the airflow. Along with this, there have also been structures that apply electrostatic force directly to the wafer surface to push out particles, which are then scattered outward through a gas flow.

[0004] However, these methods have fundamental limitations. First, since they operate only in the atmospheric pressure (ATM) range, such as EFEM, they are difficult to apply to particle control in vacuum environments. Second, simple grid-type plates have structurally limited installation space, and the low precision of charge control makes optimal control for each process environment impossible. Third, when applying charge directly to the wafer surface, there is a high risk of wafer quality degradation and defects due to electrostatic force imbalance or excessive potential, and a separate gas process is added to compensate for this, which reduces equipment operational efficiency.

[0005] Consequently, conventional technologies remain focused on atmospheric-based electrostatic precipitation, and have limitations in maintaining real-time cleanliness and controlling particle removal within the vacuum chamber.

[0006] Prior art refers to technical information that the inventor possessed for the derivation of the present invention or acquired during the process of deriving the present invention, and it cannot necessarily be considered publicly known technology disclosed to the general public prior to the filing of the present invention. Prior art literature

[0008] Republic of Korea Published Patent No. 10-2025-0103977 (Published July 8, 2025) Republic of Korea Registered Patent No. 10-2040845 (Registered October 30, 2019) The problem to be solved

[0009] In resolving the aforementioned problems, the objective of the present invention is to provide an apparatus and method capable of capturing, separating, and exhausting particles floating or entering a load lock chamber or process chamber in real time by controlling an electrostatic pad that operates stably even in a vacuum environment.

[0010] The problems that the present invention aims to solve are not limited to those mentioned above, and other problems not mentioned will be clearly understood by a person skilled in the art to which the present invention belongs from the description below. means of solving the problem

[0012] According to the particle control device in a load lock chamber using electrostatic pad control of the present invention, it may include an electrostatic pad disposed in a load lock chamber to generate electrostatic force and a control unit that controls the movement of particles present in the load lock chamber by controlling the electrostatic force by adjusting the potential applied to the electrostatic pad.

[0013] According to one embodiment, the control unit can control the movement path of the particle by detecting a change in airflow caused by any one of the opening and closing of a valve, gas supply, and pressure change within the load lock chamber, and by adjusting the potential of the electrostatic pad in real time according to the change in airflow.

[0014] According to one embodiment, the control unit can change the electrostatic force by adjusting the potential applied to the electrostatic pad in real time according to the particle concentration inside the load lock chamber.

[0015] According to one embodiment, the control unit detects an opening / closing signal of a first gate valve connecting the load lock chamber and the EFEM, controls the electrostatic pad to an off state before the first gate valve is opened, and is configured so that the opening time of the first gate valve and the wafer transfer time are synchronized, and controls the electrostatic pad to an on state after the entry of the wafer is completed and the first gate valve is closed.

[0016] According to one embodiment, the control unit may, after the wafer is completely discharged from inside the load lock chamber, switch the electrostatic pad to an off state to detach the collected particles, and simultaneously open the first gate valve and introduce purge gas into the load lock chamber so that the detached particles are discharged to the outside.

[0017] According to one embodiment, the control unit can control the electrostatic pad to be repeatedly switched between an On state and an Off state in response to a change in airflow that occurs inside the load lock chamber due to the operation of a second gate valve connected between the load lock chamber and the transfer module and a vent valve connected to the load lock chamber, thereby enabling the collection of particles inside the load lock chamber in real time.

[0018] According to one embodiment, the control unit controls the electrostatic pad to be kept in an ON state to collect particles without removing the wafer inside the load lock chamber, and after the wafer is completely discharged outside the load lock chamber, switches the electrostatic pad to an OFF state to detach the collected particles, and then injects a purge gas to discharge the particles from the load lock chamber through an exhaust port.

[0019] According to one embodiment, the control unit can correct the potential applied to the electrostatic pad based on the internal temperature of the load lock chamber.

[0020] According to one embodiment, the apparatus may further include a ceramic pad, one side of which is attached to the electrostatic pad and the other side of which is attached to the lead of the load lock chamber to form an insulating layer, and a conductive feed-through terminal that is electrically connected through the lead to transmit power supplied from an external power source and a control signal transmitted from the control unit to the electrostatic pad.

[0021] According to one embodiment, the feedthrough terminal may include a conductive conductor penetrating the lead and an insulating member formed to surround the conductive conductor to block electrical leakage between the internal vacuum region and the external atmospheric region of the loadlock chamber.

[0022] According to one embodiment, the ceramic pad is formed with a thickness greater than or equal to a reference thickness set based on the magnitude of the potential applied to the electrostatic pad and the dielectric constant of the ceramic material, thereby preventing insulation breakdown of the insulating layer formed in the ceramic pad.

[0023] According to one embodiment, the device further includes a particle counter for detecting a particle concentration within the load lock chamber, and the control unit can adjust the potential applied to the electrostatic pad based on the particle concentration detected by the particle counter.

[0024] According to one embodiment, the particle counter may be placed in at least one of the internal space of the load lock chamber and the exhaust line connected to the load lock chamber.

[0025] According to one embodiment, the electrostatic pad may be provided in an upper inner wall region and a lower inner wall region corresponding to a position where a wafer is stored within the load lock chamber.

[0026] According to one embodiment, the electrostatic pad may be provided in an inner wall area at a location adjacent to a first gate valve connecting the load lock chamber and the EFEM and a second gate valve connecting the load lock chamber and the transfer module, respectively.

[0027] According to one embodiment, the electrostatic pad is divided into a plurality of electrode regions, and the control unit may be configured to control the electrostatic force in response to the particle distribution at each location inside the load lock chamber by independently applying a potential to the plurality of electrode regions.

[0028] According to one embodiment, a fine pattern may be formed on the surface of the electrostatic pad.

[0029] According to one embodiment, the micro pattern can be implemented in the form of at least one of micro protrusions, grooves, ribs, grids, and electrode lines.

[0030] According to one embodiment, the control unit can periodically reverse the potential applied to the micro pattern to control the particle attached to the micro pattern to detach.

[0031] A method for controlling particles in a load lock chamber using electrostatic pad control according to one embodiment of the present invention may include the step of controlling electrostatic force by adjusting the potential applied to an electrostatic pad based on the internal state of the load lock chamber, and the step of controlling the movement of particles present in the load lock chamber. Effects of the invention

[0033] The present invention enables active control of particle movement within the chamber even with fluctuations in process conditions, such as valve opening / closing, gas supply, and pressure changes, by controlling the potential of an electrostatic pad placed within the load lock chamber in real time.

[0034] The control unit of the present invention can prevent the floating, re-dispersion, and re-attachment of particles by detecting changes in airflow inside the chamber and adjusting the potential of the electrostatic pad in response. In addition, the control unit of the present invention can suppress the inflow of particles from the outside during wafer transfer by detecting the opening and closing timing of the gate valve and synchronizing the on / off state of the electrostatic pad.

[0035] Alternatively, the electrostatic pad can be kept in the ON state to capture particles while the wafer is present in the chamber, and after the wafer is discharged, it can be switched to the OFF state to detach the captured particles, and then the detached particles can be discharged to the outside through the exhaust port by injecting purge gas. With this configuration, the loadlock chamber can automatically maintain internal cleanliness without a separate cleaning process.

[0036] In addition, by compensating for the potential of the electrostatic pad according to the internal temperature of the chamber, imbalances in electrostatic force caused by temperature changes can be prevented, and the stability of collection efficiency can be ensured. Furthermore, since the electrostatic pad is attached to the lead via a ceramic pad to ensure electrical insulation, and power and control signals are stably transmitted through the feed-through terminal, electrical leakage between vacuum and atmosphere can be prevented.

[0037] In addition, the micro-pattern on the surface of the electrostatic pad in the present invention improves particle collection efficiency by locally concentrating the electric field, and the structure of multiple electrode regions enables independent potential control according to the particle distribution by location, thereby realizing precise control by space.

[0038] Therefore, the present invention relates to particles generated or introduced inside a load lock chamber.

[0039] By capturing and removing in real time, wafer contamination can be prevented and process yield improved, while extending equipment maintenance cycles and increasing production efficiency.

[0040] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by a person skilled in the art to which the present invention pertains from the description below. Brief explanation of the drawing

[0042] FIG. 1 is a flowchart illustrating a method for controlling particles in a load lock chamber using electrostatic pad control according to one embodiment. FIG. 2 is a diagram illustrating a configuration for controlling particles using an electrostatic pad installed on the lead of a load lock chamber according to one embodiment. FIG. 3 is a diagram showing a gas flow path within a load lock chamber according to one embodiment. FIG. 4 is a diagram illustrating the feature of capturing particles flowing according to a change in state within a load lock chamber according to one embodiment. FIG. 5 is a drawing illustrating the feature of cleaning the inside of a load lock chamber without separating the electrostatic pad according to one embodiment. FIG. 6 is a drawing illustrating technical features for preventing the capture of unintentional particles according to one embodiment. Specific details for implementing the invention

[0043] In the present invention, the attached drawings may be illustrated with exaggerated expressions to distinguish it from the prior art, ensure clarity, and facilitate the understanding of the technology. Furthermore, the terms described below are defined considering their functions in the present invention; since these terms may vary depending on the intentions or conventions of the user or operator, their definitions should be based on the technical content throughout this specification. Meanwhile, the embodiments are merely exemplary details of the components presented in the claims of the present invention and do not limit the scope of the rights of the present invention; the scope of rights should be interpreted based on the technical concept throughout the specification of the present invention.

[0044] Throughout the specification, when a configuration is described as "including" a configuration, this means that, unless specifically stated otherwise, it does not exclude other configurations but may include additional configurations.

[0045] Furthermore, when it is said that one configuration is "connected," "connected," or "combined" with another configuration, this means that it is not only "directly connected," "directly connected," or "directly combined," but also that there may be cases where it is "connected with another configuration interposed," "connected with another configuration interposed," or "combined with another configuration interposed." On the other hand, when it is said that one configuration is "directly connected," "directly connected," or "directly combined" with another configuration, it should be understood that there is no other configuration in between.

[0046] In addition, when directional terms such as "front," "back," "up," "down," "left," "right," "first end," "other end," and "both ends" are used, they are used exemplarily in relation to the orientation of the disclosed drawings and should not be interpreted restrictively, and when terms such as "first" and "second" are used, they are terms used to distinguish each configuration and should not be interpreted restrictively.

[0047] In order to more clearly explain the features of the embodiments of the present invention, detailed descriptions of matters widely known to those skilled in the art to which the following embodiments pertain are omitted. Additionally, detailed descriptions of parts in the drawings that are unrelated to the description of the embodiments are omitted.

[0049] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0050] FIG. 1 is a flowchart illustrating a method for controlling particles in a load lock chamber using electrostatic pad control according to one embodiment; FIG. 2 is a diagram illustrating a configuration for controlling particles using an electrostatic pad installed on the lead of a load lock chamber according to one embodiment; FIG. 3 is a diagram showing a gas flow path within a load lock chamber according to one embodiment; FIG. 4 is a diagram illustrating a feature for capturing particles flowing according to a change in state within a load lock chamber according to one embodiment; FIG. 5 is a diagram illustrating a feature for cleaning the inside of a load lock chamber without separating the electrostatic pad according to one embodiment; and FIG. 6 is a diagram illustrating a technical feature for preventing the capture of unintentional particles according to one embodiment.

[0052] The particle control device (10) in a load lock chamber using electrostatic pad control of the present invention may include an electrostatic pad (100) and a control unit (200).

[0053] According to one embodiment, the electrostatic pad (100) operates on the principle of forming an electric field by applying a potential to an electrode, and capturing or moving particles floating in the air or attached to a surface by electrostatic force through the electric field. Generally, the electrostatic pad (100) to which the potential is applied induces a charge of opposite polarity to the charged particles to generate an adsorption force, thereby causing the particles to be attracted to and attached to the surface of the pad. When the power is cut off and the potential is released, the electrostatic field disappears, and the captured particles are detached and can be discharged by an external airflow or purge gas. In this way, the electrostatic pad (100) can repeatedly perform the capture and detachment of particles by controlling the potential, and can be utilized for contamination control in vacuum chambers, cleanroom facilities, semiconductor manufacturing equipment, etc.

[0054] According to FIG. 1, a particle control method in a load lock chamber using electrostatic pad control according to one embodiment of the present invention may include a step (S10) of controlling an electrostatic force by adjusting the potential applied to the electrostatic pad (100) based on the internal state of the load lock chamber (20), and a step (S20) of controlling the movement of particles present in the load lock chamber (20).

[0055] According to one embodiment, the present invention has the advantage that the control unit (200) can dynamically adjust the potential applied to the electrostatic pad (100) in accordance with real-time changes such as internal pressure, gas flow, valve opening / closing state, and particle concentration of the load lock chamber (20), thereby actively controlling the movement, attachment, and re-dispersion of particles generated or floating inside the load lock chamber (20). Accordingly, contamination caused by minute vibrations or airflow changes occurring during wafer transfer inside the load lock chamber (20) can be prevented, the cleanliness inside the load lock chamber (20) can be automatically maintained in accordance with the process state, and the operating efficiency and yield of the equipment can be improved without an additional cleaning process.

[0057] Referring to FIG. 2, the electrostatic pad (100) can be attached to the lead (21) of the load lock chamber (20).

[0058] According to one embodiment, the load lock chamber (20) performs the function of buffering the pressure difference between the outside air and the process area during wafer transfer between the EFEM and the transfer module, and has a structure that repeatedly switches between a vacuum state and an atmospheric state. Since particles may be generated or suspended during this repeated pressure change process, maintaining cleanliness is very important.

[0059] According to one embodiment, the present invention may include an electrostatic pad (100) disposed within the load lock chamber (20) to generate electrostatic force, and a control unit (200) that controls the movement of particles present inside by controlling the electrostatic force by adjusting the potential applied to the electrostatic pad (100).

[0060] According to one embodiment, the ceramic pad (110), one side of which is attached to the electrostatic pad (100) and the other side of which is attached to the lead (21) of the load lock chamber (20) to form an insulating layer, and a conductive feed-through terminal connected by electrically penetrating the lead (21) to transmit power supplied from an external power source and a control signal transmitted from the control unit (200) to the electrostatic pad (100) may be further included.

[0061] According to one embodiment, the feedthrough terminal (120) may include a conductive conductor penetrating the lead (21) and an insulating member formed to surround the conductive conductor to block electrical leakage between the internal vacuum region and the external atmospheric region of the loadlock chamber (20).

[0062] According to one embodiment, the ceramic pad (110) is formed with a thickness greater than or equal to a reference thickness set based on the magnitude of the potential applied to the electrostatic pad (100) and the dielectric constant of the ceramic material, thereby preventing insulation breakdown of the insulating layer formed in the ceramic pad (110).

[0063] According to one embodiment, a feed-through terminal (120) is provided on the upper part of the ceramic pad (110), and the feed-through terminal (120) serves as a conductive passage for transmitting power supplied from an external power supply unit (400) and a control signal from a control unit (200) to the electrostatic pad (100).

[0064] According to one embodiment, the feedthrough terminal (120) is electrically connected by penetrating the loadlock chamber lid (21), and includes a conductive conductor inside and an insulating member formed on the outside to block electrical leakage between the vacuum region of the loadlock chamber (20) and the external atmosphere region.

[0065] According to one embodiment, the device further includes a particle counter (300) for detecting a particle concentration within the load lock chamber (20), and the control unit (200) can adjust the potential applied to the electrostatic pad (100) based on the particle concentration detected by the particle counter (300).

[0066] According to one embodiment, the particle counter (300) may be placed in at least one of the internal space of the load lock chamber (20) and the exhaust line connected to the load lock chamber (20). According to one embodiment, the particle counter (300) can quantitatively determine the particle removal efficiency by measuring the concentration of particles emitted during the purge gas injection or exhaust process. Based on this data, the control unit (200) performs potential control of the electrostatic pad (100) and flow rate control of the purge gas to efficiently remove particles inside the chamber.

[0067] According to one embodiment, the particle counter (300) detects changes in particle concentration inside the load lock chamber (20) in real time, and the detected data is transmitted to the control unit (200) and can be used to correct or control the potential applied to the electrostatic pad (100). Through this, the control unit (200) can maintain the cleanliness inside the load lock chamber (20), prevent the accumulation or re-dispersion of fine particles generated during the process, and efficiently control the adsorption and desorption of particles by adjusting the potential of the electrostatic pad (100) in stages when necessary.

[0068] According to one embodiment, when the particle counter (300) is installed in the exhaust line, the particle removal efficiency during the purge gas injection or exhaust process can be quantitatively evaluated by directly monitoring the concentration of particles discharged from inside the load lock chamber (20).

[0069] According to one embodiment, the control unit (200) can correct the potential applied to the electrostatic pad (100) based on the internal temperature of the load lock chamber (20).

[0070] According to one embodiment, the control unit (200) can detect the internal temperature of the load lock chamber (20) in real time and correct the potential of the electrostatic pad (100) according to the temperature change. This is because, as the load lock chamber (20) repeats the vacuum, heating, and cooling processes, if the temperature of the inner wall of the load lock chamber (20) changes, the dielectric constant of the electrode and insulating layer constituting the electrostatic pad (100) changes, and accordingly, the strength of the electrostatic force actually generated at the same applied voltage may change.

[0071] For example, when the internal temperature of the load lock chamber (20) rises, the dielectric constant of the ceramic pad (110) decreases, and accordingly, the strength of the electric field formed on the electrostatic pad (100) decreases. In response to this, the control unit (200) can control the voltage applied to the electrostatic pad (100) by adjusting it at a certain ratio based on temperature information transmitted from a temperature sensor or a chamber controller, so that a constant electrostatic force is maintained regardless of temperature changes.

[0072] In addition, the control unit (200) can store a temperature correction table or a correction algorithm in memory and select and apply an optimal applied voltage for each temperature range. With such a configuration, the potential stability of the electrostatic pad (100) is secured even in high or low temperature environments, thereby minimizing deviations in particle collection performance and maintaining uniform control characteristics even during long-term operation.

[0073] Accordingly, the temperature-based potential correction function according to one embodiment of the present invention can prevent electrostatic force imbalance caused by the internal thermal environment of the load lock chamber (20) and contribute to stably maintaining particle collection efficiency.

[0075] Referring to FIG. 3, the load lock chamber (20) is connected to the EFEM through the first gate valve (22) and to the transfer chamber through the second gate valve (23). According to one embodiment, the load lock chamber (20) buffers the pressure difference between the outside air and the vacuum area during the process of loading and unloading wafers, and performs atmospheric and exhaust operations through the vent valve (24) and the exhaust port (25). During this process, particles attached to the wafer surface or the inner wall of the chamber may be re-dispersed or move, causing contamination.

[0076] According to one embodiment, the electrostatic pad (100) may be provided in an upper inner wall region and a lower inner wall region corresponding to the position where the wafer is stored within the load lock chamber (20). By positioning the electrostatic pad (100) opposite the upper and lower inner walls in this manner, the electric field in the vertical direction of the wafer is uniformly formed, so that particles can be stably collected without being concentrated on the chamber wall or the wafer surface.

[0077] In addition, by independently adjusting the potential of the upper pad (100_1) and the lower pad (100_2), the symmetry of the electrostatic field within the chamber can be maintained while effectively suppressing the floating and re-dispersion of particles. This arrangement forms a uniform electric field inside the chamber during the wafer's loading, unloading, or standby state, thereby preventing particles from being concentrated on the chamber walls.

[0078] According to one embodiment, the electrostatic pad (100) may be provided in an inner wall area adjacent to a first gate valve (22) connecting the load lock chamber (20) and the EFEM, and a second gate valve (23) connecting the load lock chamber (20) and the transfer module. This is to control the phenomenon in which particles move in the inflow and outflow directions according to changes in airflow that may occur when the wafer is introduced through the first gate valve (22) or discharged through the second gate valve (23). Accordingly, the electrostatic pad (100) can perform the function of blocking particle inflow and inducing flow in the outflow direction by immediately adjusting the potential polarity in response to changes in pressure inside the chamber when the gate valve is opened or closed.

[0079] According to one embodiment, the electrostatic pad (100) is formed by dividing it into a plurality of electrode regions, and the control unit (200) may be configured to control the electrostatic force in response to the particle distribution by location inside the load lock chamber (20) by independently applying a potential to the plurality of electrode regions. At this time, each electrode region is controlled based on particle concentration data received in real time from the particle counter (300), and the potential of the region may be set to automatically rise when a high particle density is detected in a specific section inside the load lock chamber (20). Through this, the electric field distribution inside the chamber is dynamically corrected, thereby mitigating the imbalance in particle concentration by location and preventing local contamination.

[0080] According to one embodiment, the electrostatic pad (100) may have a fine pattern formed on its surface. The fine pattern controls the attachment area of ​​particles captured by electrostatic force and finely disperses the surface potential distribution to prevent charge from concentrating at a specific location. Accordingly, insulation breakdown or localized heating caused by surface potential imbalance is minimized even during long-term operation.

[0081] According to one embodiment, the micro pattern may be implemented in the form of at least one of micro protrusions, grooves, ribs, grids, and electrode lines. Such a pattern structure can disperse charge accumulation according to the size and movement path of the particles, and in particular, when a grid or rib structure is applied, the captured particles move naturally according to changes in the airflow or electric field inside the chamber and are guided toward the exhaust port (25).

[0082] According to one embodiment, the control unit (200) can control the particle attached to the micro pattern to detach by periodically reversing the potential applied to the micro pattern. Such periodic potential reversal prevents the phenomenon where the captured particle adheres to the surface by maintaining the electrostatic force for a certain period of time, and induces the detached particle to be discharged to the outside through the vent valve (24) or exhaust port (25), thereby suppressing the accumulation of long-term contamination in the chamber. Consequently, the potential reversal control of the control unit (200) can be a key technological element for realizing the self-cleaning function of the electrostatic pad (100).

[0084] According to one embodiment, the control unit (200) can control the movement path of the particle by detecting a change in airflow caused by any one of the opening and closing of a valve, gas supply, and pressure change within the load lock chamber (20), and by adjusting the potential of the electrostatic pad (100) in real time according to the change in airflow.

[0085] According to one embodiment, as illustrated in FIG. 4, the control unit (200) can actively control the electric field distribution so that particles are adsorbed to the electrode surface or discharged along the exhaust flow by detecting in real time the pressure difference formed by the opening and closing operation of the first gate valve (22) or the second gate valve (23) and the change in the direction of airflow near the exhaust port (25), thereby changing the potential of the electrostatic pad (100) in steps. Accordingly, despite rapid pressure fluctuations inside the load lock chamber (20), the particles do not float irregularly but move along a stable path.

[0086] According to one embodiment, the control unit (200) can change the electrostatic force by adjusting the potential applied to the electrostatic pad (100) in real time according to the particle concentration inside the load lock chamber (20).

[0087] As illustrated in FIGS. 5(a) and 5(b), the control unit (200) can correct the potential control frequency and applied voltage in real time based on particle concentration information detected from the particle counter (300). For example, if the concentration of particles in the load lock chamber (20) increases, the potential of the electrostatic pad (100) is raised to strengthen the electrostatic adsorption force, and conversely, if the concentration decreases, the potential is gradually reduced to prevent unnecessary energy consumption. Through such feedback control, the particle collection efficiency and energy efficiency inside the load lock chamber (20) can be improved simultaneously.

[0088] According to one embodiment, the control unit (200) detects the opening and closing signal of the first gate valve (22) connecting the load lock chamber (20) and the EFEM, controls the electrostatic pad (100) to be off before the first gate valve (22) is opened, and is configured so that the opening time of the first gate valve (22) and the wafer transfer time are synchronized, and controls the electrostatic pad (100) to be on after the entry of the wafer is completed and the first gate valve (22) is closed.

[0089] According to one embodiment, the electrostatic pad (100) is already switched to the off state when the first gate valve (22) is opened, which matches the airflow pattern of the wafer loading step shown in FIG. 4, thereby preventing residual particles on the wafer surface from being unnecessarily adsorbed or repelled by the electric field. Here, when the electrostatic pad (100) returns to the on state after the wafer is completely loaded, residual particles are quickly captured on the electrode surface along with the stabilization of the airflow inside the chamber. Through such synchronous control, particle re-dispersion and contamination adhesion that may occur during wafer loading can be effectively suppressed.

[0090] According to one embodiment, the control unit (200) can switch the electrostatic pad (100) to an off state after all wafers have been discharged from inside the load lock chamber (20) to detach the collected particles, and simultaneously open the first gate valve (22) and introduce purge gas into the load lock chamber (20) so that the detached particles are discharged to the outside.

[0091] According to one embodiment, the control unit (200) can control the electrostatic pad (100) to be repeatedly switched between an On state and an Off state in response to the change in airflow when a change in airflow occurs inside the load lock chamber (20) due to the operation of a second gate valve (23) connected between the load lock chamber (20) and a transfer module and a vent valve (24) connected to the load lock chamber (20), thereby enabling the collection of particles inside the load lock chamber (20) in real time.

[0092] As shown in the series of operations of FIG. 5, the control unit (200) simultaneously monitors the exhaust airflow generated when the second gate valve (23) is opened and the flow of gas injected through the vent valve (24). Accordingly, the electrostatic pad (100) is periodically turned on and off to prevent particles from adhering to a specific wall surface for a long time and to suppress the accumulation of contamination inside the chamber by minimizing the residence time of the particles. This repetitive control method implements a self-cleaning cycle that periodically performs particle collection and detachment, thereby stably maintaining the cleanliness of the load lock chamber (20) even during long-term operation.

[0093] More specifically, FIG. 5(a) shows the process of particles being adsorbed when the electrostatic pad is in the ON state, FIG. 5(b) shows the process of particles being separated when the electrostatic pad is switched to the OFF state, and FIG. 5(c) shows the process of particles being discharged to the outside through the exhaust port.

[0094] According to one embodiment, with reference to FIG. 5(a), a plurality of electrostatic pads (100) are arranged facing each other on the upper and lower sides of the inner wall of the load lock chamber (20). The electrostatic pads (100) are kept in an ON state by applying power, and apply electrostatic force to particles (1000) generated or introduced inside the load lock chamber (20) to adsorb them to the surface. At this time, the control unit (200) can control the electric field so that it is not concentrated in a specific section inside the load lock chamber (20) by adjusting the intensity of the electric potential based on the particle concentration detected by the particle counter (300).

[0095] In this electrostatic adsorption step, the purge gas introduced through the vent path is dispersed into the chamber, and the floating particles (1000) are stably guided to the surface of the electrostatic pad (100).

[0096] Next, referring to FIG. 5(b), the control unit (200) switches the power of the electrostatic pad (100) to an OFF state after a certain period of time has elapsed. Accordingly, the electric field formed by the electrostatic pad (100) is extinguished, and the particles (1000) attached to the surface are released from the electrostatic force and switch to a floating state. In this step, the gas injected through the vent path is controlled to flow toward the center of the chamber, and the particles (1000) move toward the exhaust port (25) along the airflow. That is, a particle separation step is performed in which the particles (1000) are carried by the airflow by removing the electrostatic force.

[0097] Finally, referring to FIG. 5(c), the control unit (200) increases the flow rate of the gas injected through the vent path or increases the pumping speed of the exhaust port (25) to form a pressure gradient inside the chamber. Accordingly, the particles (1000) pass through the center of the load lock chamber (20) and are discharged to the outside through the exhaust port (25). At this time, the electrostatic pad (100) is kept in an off state to prevent re-adsorption of the particles (1000), and when the residual particle concentration inside the chamber drops below a reference value through the particle counter (300), the control unit (200) can switch the electrostatic pad (100) back to an on state to start a new collection cycle.

[0099] According to one embodiment, the control unit (200) can control the electrostatic pad (100) to be kept in an ON state to collect particles without removing the wafer inside the load lock chamber (20), and after the wafer is completely discharged outside the load lock chamber (20), the electrostatic pad (100) is switched to an OFF state to remove the collected particles, and then the control unit can control the injection of purge gas to discharge the particles from the load lock chamber (20) through the exhaust port (25).

[0100] FIG. 6 is a diagram illustrating the process of preventing the capture of unintended particles after wafer discharge and discharging particles remaining inside the chamber using a gas flow in the EFEM direction in a particle control device in a load lock chamber using electrostatic pad control according to an embodiment of the present invention.

[0101] Referring to FIG. 6, the load lock chamber (20) is maintained with the second gate valve (23) in the direction of the transfer module closed and the first gate valve (22) in the direction of the EFEM open. At this time, the control unit (200) confirms that the wafer has been completely discharged and switches the power applied to the electrostatic pad (100) to the off state to release the electrostatic force. As a result, the particles attached to the surface of the electrostatic pad (100) are released from the electrostatic force and transition to a floating state.

[0102] In this state, the control unit (200) can open the vent valve (24) while the roughing valve is closed to inject N2 gas from the EFEM side atmospheric pressure (ATM) environment into the load lock chamber (20). The roughing valve is connected to the vacuum pump line of the load lock chamber (20) and is configured as a valve for depressurizing the inside of the load lock chamber (20), and the vent valve (24) is connected to the N2 gas supply line and is configured as a valve for returning the inside of the load lock chamber (20) to atmospheric pressure. At this time, the two valves are connected in a T-shape to a single exhaust line, and the control unit (200) controls their opening and closing mutually exclusively, thereby preventing pressure interference between the vacuum formation and gas injection processes and stably maintaining the particle discharge path inside the chamber.

[0103] According to one embodiment, the N2 gas injected at this time flows along the EFEM gas flow path and performs the function of pushing out particles remaining along the area around the electrostatic pad (100) and the inner wall of the load lock chamber (20). The injection time of the N2 gas is maintained for a stable time set according to the equipment operating conditions, and during this period, particles remaining inside the load lock chamber (20) are completely discharged in the direction of the EFEM. Afterwards, the control unit (200) closes the first gate valve (22) in the direction of the EFEM and performs a cleaning sequence in the next step.

[0104] According to one embodiment, the cleaning sequence is a step of removing fine particles remaining on the inner wall of the chamber and the surface of the electrostatic pad (100) after purging the N2 gas, and can be performed repeatedly as needed. In addition, the control unit (200) can monitor the cleanliness inside the load lock chamber (20) in real time using a particle counter (300) and can repeatedly control the discharge and cleaning sequence until the measured particle concentration reaches a set stable range.

[0105] Consequently, according to the embodiment illustrated in FIG. 6, the control unit (200) releases the electrostatic force after wafer ejection and uses the EFEM-side vent gas, thereby preventing external particles or unintended particles from being captured inside the chamber and efficiently discharging particles remaining inside the load lock chamber (20) in the direction of atmospheric pressure. This minimizes equipment contamination and allows the cleanliness of the load lock chamber to be stably maintained through repetitive cleaning sequence control.

[0107] As described above, the present invention has been explained with reference to the embodiments illustrated in the drawings, but this is merely illustrative, and it should be understood that various modifications and equivalent alternative embodiments are possible based on the ordinary knowledge of the art to which the art belongs. Accordingly, the true technical scope of protection of the present invention is defined by the claims described below and should be determined based on the specific details of the invention described above. Industrial applicability

[0109] The present invention relates to a particle control device and method in a load lock chamber using electrostatic pad control, and can be applied to manufacturing process fields requiring cleanliness of the load lock chamber, such as semiconductor manufacturing equipment.

[0110] No content Explanation of the symbols

[0111] 10: Particle control device in a load lock chamber using electrostatic pad control 20: Loadlock Chamber 21: Loadlock Chamber Lead 22: 1st Gate Valve 23: Second Gate Valve 24: Vent valve 25: Exhaust port 100: Electrostatic pad 110: Ceramic pad 120: Feedthrough terminal 130: Power supply 200: Control unit 300: Particle Counter

Claims

Claim 1 A particle control device in a load lock chamber using electrostatic pad control, comprising: an electrostatic pad disposed within a load lock chamber to generate electrostatic force; and a control unit that controls the movement of particles present within the load lock chamber by controlling the electrostatic force through adjusting the potential applied to the electrostatic pad; wherein the electrostatic pad is formed by dividing it into a plurality of electrode regions, and the control unit is configured to control the electrostatic force in correspondence with the particle distribution by position within the load lock chamber by independently applying potential to the plurality of electrode regions. Claim 2 A particle control device in a load lock chamber using electrostatic pad control, wherein, in claim 1, the control unit detects a change in airflow caused by any one of the opening and closing of a valve, gas supply, and pressure change in the load lock chamber, and controls the movement path of the particle by adjusting the potential of the electrostatic pad in real time according to the change in airflow. Claim 3 A particle control device in a load lock chamber using electrostatic pad control, wherein, in claim 1, the control unit changes the electrostatic force by adjusting the potential applied to the electrostatic pad in real time according to the particle concentration inside the load lock chamber. Claim 4 A particle control device in a load lock chamber using electrostatic pad control according to claim 1, wherein the control unit detects an opening / closing signal of a first gate valve connecting the load lock chamber and the EFEM, controls the electrostatic pad to an off state before the first gate valve is opened, is configured so that the opening time of the first gate valve and the wafer transfer time are synchronized, and controls the electrostatic pad to an on state after the entry of the wafer is completed and the first gate valve is closed. Claim 5 A particle control device in a load lock chamber using electrostatic pad control, wherein, in claim 4, the control unit switches the electrostatic pad to an off state after all wafers are discharged from inside the load lock chamber to detach particles collected on the electrostatic pad, and simultaneously opens the first gate valve and introduces purge gas into the load lock chamber so that the detached particles are discharged to the outside. Claim 6 A particle control device for a load lock chamber using electrostatic pad control according to claim 1, wherein the control unit controls the electrostatic pad to be repeatedly turned on and off in response to the change in airflow when a change in airflow occurs inside the load lock chamber due to the operation of a second gate valve connected between the load lock chamber and the transfer module and a vent valve connected to the load lock chamber, thereby controlling the collection of particles inside the load lock chamber in real time. Claim 7 A particle control device in a load lock chamber using electrostatic pad control according to claim 1, wherein the control unit controls the electrostatic pad to be kept in an ON state to collect particles without removing the wafer inside the load lock chamber, switches the electrostatic pad to an OFF state to detach the collected particles after the wafer is completely discharged outside the load lock chamber, and then controls the injection of purge gas to discharge the particles from the load lock chamber through an exhaust port. Claim 8 A particle control device in a load lock chamber using electrostatic pad control, wherein, in claim 1, the control unit corrects the potential applied to the electrostatic pad based on the internal temperature of the load lock chamber. Claim 9 A particle control device in a load lock chamber using electrostatic pad control, further comprising: a ceramic pad having one side attached to the electrostatic pad and the other side attached to the lead of the load lock chamber to form an insulating layer in claim 1; and a conductive feed-through terminal connected by electrically penetrating the lead to transmit power supplied from an external power source and a control signal transmitted from the control unit to the electrostatic pad. Claim 10 A particle control device in a load lock chamber using electrostatic pad control, characterized in that, in claim 9, the feedthrough terminal comprises: a conductive conductor penetrating the lead; and an insulating member formed to surround the conductive conductor to block electrical leakage between the internal vacuum region and the external atmospheric region of the load lock chamber. Claim 11 A particle control device in a load lock chamber using electrostatic pad control, characterized in that, in claim 9, the ceramic pad is formed with a thickness greater than or equal to a reference thickness set based on the magnitude of the potential applied to the electrostatic pad and the dielectric constant of the ceramic material, thereby preventing dielectric breakdown of the insulating layer formed in the ceramic pad. Claim 12 A particle control device in a load lock chamber using electrostatic pad control, wherein, in claim 8, it further comprises a particle counter for detecting a particle concentration in the load lock chamber, and the control unit adjusts the potential applied to the electrostatic pad based on the particle concentration detected by the particle counter. Claim 13 A particle control device in a load lock chamber using electrostatic pad control, characterized in that, in claim 12, the particle counter is disposed in at least one of the internal space of the load lock chamber and the exhaust line connected to the load lock chamber. Claim 14 A particle control device in a load lock chamber using electrostatic pad control, characterized in that, in claim 1, the electrostatic pad is provided in an upper inner wall region and a lower inner wall region corresponding to a position where a wafer is housed in the load lock chamber. Claim 15 A particle control device in a load lock chamber using electrostatic pad control according to claim 1, wherein the electrostatic pad is respectively provided in an inner wall area at a position adjacent to a first gate valve connecting the load lock chamber and the EFEM and a second gate valve connecting the load lock chamber and the transfer module. Claim 16 delete Claim 17 A particle control device in a load lock chamber using electrostatic pad control, wherein, in claim 1, the electrostatic pad is characterized by having a fine pattern formed on its surface. Claim 18 A particle control device in a load lock chamber using electrostatic pad control, characterized in that, in claim 17, the micro pattern is implemented in at least one form among micro protrusions, grooves, ribs, grids, and electrode lines. Claim 19 A particle control device in a load lock chamber using electrostatic pad control according to claim 17, wherein the control unit periodically reverses the potential applied to the micro pattern to control the detachment of particles attached to the micro pattern. Claim 20 A method for controlling particles in a load lock chamber using electrostatic pad control, comprising: a step of controlling electrostatic force by adjusting the potential applied to an electrostatic pad based on the internal state of the load lock chamber; and a step of controlling the movement of particles present in the load lock chamber; wherein the step of controlling electrostatic force is characterized by controlling the electrostatic force in correspondence with the particle distribution by position within the load lock chamber by independently applying a potential to a plurality of electrode regions divided and formed in the electrostatic pad.

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