Vacuum equipment front end module

Abstract

One embodiment provides a vacuum EFEM comprising: a loader in which a Front Opening Unified Pod (FOUP) is lowered in an atmospheric pressure atmosphere; and an Equipment Front End Module (EFEM) chamber disposed on the side of the loader between a Vacuum Transfer Module (VTM) and the loader, wherein the FOUP is introduced and seated on the side upon opening of a first valve, the internal space is converted to a vacuum atmosphere after closing of the first valve, and an aligner is disposed on the upper side of the space where the FOUP is seated.

Description

Technology Field

[0001] This embodiment relates to an Equipment Front End Module (EFEM) used in a semiconductor process. Background Technology

[0002] Semiconductor manufacturing equipment typically includes a front module called an Equipment Front End Module (EFEM) to transport wafers into the process equipment and to transport them out after the process is completed. The EFEM is positioned at the front of the semiconductor process equipment and serves as an interface to transport wafers stored in a Front Opening Unified Pod (FOUP) into the equipment. It is responsible for functions such as the loading and unloading of wafers, opening and closing of the FOUP, wafer alignment, and robot control for transport to each process module.

[0003] Generally, the EFEM includes an LPM (Load Port Module), a robot for extracting wafers, and an EFEM chamber, and forms a series of paths in which a FOUP is supplied from an external transfer device (OHT, Overhead Hoist Transport), placed on the LPM of the EFEM, transferred to a Load Lock via a robot, and then transferred to each process chamber via a VTM (Vacuum Transfer Module).

[0004] Here, the internal space of the EFEM maintains an atmospheric pressure atmosphere, and the internal space of the VTM maintains a vacuum atmosphere for process execution; the load lock functions as an intermediate medium between the EFEM and the VTM, serving as a pressure transition space that converts the wafer from an atmospheric pressure state to a vacuum state. In other words, the load lock acts as a buffer zone connecting the EFEM and the VTM and buffering the pressure difference between the two spaces, enabling the VTM to maintain a vacuum state even when the EFEM is in an open atmospheric environment.

[0005] However, this structure inevitably requires multiple chambers, valves, and gate interfaces, leading to problems such as a complex overall equipment structure and increased bulk. In particular, since the load lock exists separately between the EFEM and VTM, the longitudinal space of the equipment increases significantly, making it difficult to efficiently utilize the limited cleanroom area in semiconductor production lines. As the installation space for semiconductor process equipment is strictly limited considering cleanliness, cooling, and vibration suppression, the space occupied by the load lock module reduces the integration density of production facilities and hinders accessibility during equipment maintenance. Consequently, placement flexibility between process equipment is reduced, and additional infrastructure changes are required during line relocation or expansion.

[0006] In addition, if an aligner for aligning wafer orientation is installed outside the EFEM or in a separate chamber, the aligner chamber occupies additional installation space, increasing the overall size of the equipment and causing problems such as interference between equipment or complicating maintenance paths. In particular, in systems that transport wafers in a high vacuum environment, if the aligner is separated from the EFEM, there is a higher likelihood that the wafer will be exposed to ambient air or contaminants during the alignment process, and system complexity and costs increase because a separate vacuum interface and control system are required.

[0007] In this structure, the atmosphere inside the EFEM becomes virtually identical to that of a cleanroom. For example, the temperature, pressure, and humidity inside the EFEM are maintained within the controlled range of a cleanroom; since the relative humidity of a cleanroom is typically managed at around 40%, the humidity inside the EFEM is also maintained at around 40%. However, as the miniaturization of semiconductor devices continues, these humidity conditions have a direct impact on the quality of the wafer.

[0008] With the recent increase in semiconductor device integration density, the linewidth of circuit patterns on wafers is shrinking to tens of nanometers or less, and the spacing between patterns is also showing a tendency to become increasingly narrow. In such ultrafine structures, the likelihood of moisture from the air adsorbing onto the wafer surface or condensing in micro-gap increases, which can lead to defects such as short circuits between patterns, surface oxidation, and the formation of micro-contamination layers. Even the temporary retention of moisture on the wafer surface can adversely affect process quality, such as altering electrical properties or degrading the uniformity of photoresponse during the photolithography process.

[0009] Furthermore, as process miniaturization progresses, the impact of trace amounts of airborne molecular contamination (AMC) contained in the atmosphere or particles generated from internal components of the EFEM also increases. Since the interior of the EFEM is structured to allow cleanroom air to circulate, AMC, organic gases, and metal volatiles generated from external or adjacent equipment can enter the EFEM. When these contaminants adhere to the wafer surface, they cause defects during various process steps, such as photolithography, etching, and deposition. This can lead to problems such as short circuits, thin film non-uniformity, and pattern distortion, which consequently cause a decrease in device yield or an increase in process reprocessing costs.

[0010] As such, since a standard EFEM operates under atmospheric pressure and a humidity level of about 40%, it has limitations in that it is difficult to completely suppress moisture adsorption and contaminant exposure on the wafer. In addition, due to the complex structure including the load lock and aligner chamber, there are problems such as low space utilization efficiency of the equipment and reduced flexibility of production line layout. The problem to be solved

[0011] Against this backdrop, the objective of the present embodiment is, in one aspect, to provide an Equipment Front End Module (EFEM) that can fundamentally block the wafer from being exposed to moisture in the atmosphere or airborne molecular contaminants (AMC) by configuring the EFEM itself in a vacuum atmosphere.

[0012] In another aspect, the objective of the present embodiment is to provide an EFEM that can simplify the overall structure of the equipment and maximize space utilization efficiency within a semiconductor process line by maintaining the internal space of the EFEM in a vacuum state without having a separate Load Lock module.

[0013] In another aspect, the objective of the present embodiment is to provide an EFEM that can improve the layout efficiency of a production line by reducing the overall volume of the equipment and eliminating the need to install a separate aligner chamber by placing an aligner, which performs the wafer alignment function, inside the EFEM chamber, that is, above the space where the FOUP is seated.

[0014] In addition, the objective of the present embodiment is to provide an EFEM capable of efficiently removing moisture and contaminant gases inside the EFEM and forming a stable and clean vacuum environment by performing nitrogen (N2) purge and vacuum exhaust in parallel during the process of switching from an atmospheric pressure state to a vacuum atmosphere when the pod is supplied from the outside. means of solving the problem

[0015] To achieve the aforementioned objective, one embodiment provides a vacuum EFEM comprising: a loader in which a Front Opening Unified Pod (FOUP) is lowered in an atmospheric pressure atmosphere; and an Equipment Front End Module (EFEM) chamber disposed on the side of the loader between a Vacuum Transfer Module (VTM) and the loader, wherein the FOUP is introduced and seated on the side upon opening of a first valve, the internal space is converted to a vacuum atmosphere after closing of the first valve, and an aligner is disposed on the upper side of the space where the FOUP is seated.

[0016] With the above EFEM chamber and the above VTM in communication, a vacuum robot placed inside the VTM can extract wafers stored in the above pod and transfer them to the process chamber.

[0017] The vacuum robot can withdraw a wafer from the pod, align the wafer through the aligner, and then move it to the process chamber.

[0018] The pod seated on the loader can be slid into the internal space of the EFEM chamber by means of a sliding moving device positioned on the lower side.

[0019] The above EFEM chamber is switched to a vacuum atmosphere after the pod is introduced from the side and the first valve is closed, and after all processes for the wafers contained in the pod are completed, the second valve positioned between it and the VTM is closed and the chamber is switched back to an atmospheric pressure atmosphere, and after the chamber is switched to an atmospheric pressure atmosphere, the first valve is opened to allow the pod to be discharged from the side to the loader.

[0020] When the air pressure of the EFEM chamber approaches the air pressure of the VTM within a certain range, the second valve may be opened.

[0021] In the above EFEM chamber, after the pod is introduced from the side and the first valve is closed, N2 (nitrogen) is purged into the internal space, and subsequently, the internal space can be converted to a vacuum atmosphere through vacuum evacuation.

[0022] The door of the above-mentioned pod may be opened when N2 is purged into the internal space, after N2 is purged, or before N2 is purged.

[0023] After all processes for the wafers housed in the above pod are completed, the second valve positioned between the EFEM chamber and the VTM is closed, and N2 (nitrogen) can be purged into the internal space of the EFEM chamber.

[0024] After N2 is purged into the internal space of the EFEM chamber and the air pressure rises to a certain level, the door of the pod can be closed and the first valve can be opened.

[0025] When viewed in a planar view, the first direction in which the pod moves from the loader to the EFEM chamber may be a direction that is not perpendicular or horizontal to the second direction in which the pod approaches from the OHT (Overhead Hoist Transport).

[0026] The loader can rotate the seated pod in the first direction from a direction corresponding to the second direction.

[0027] The above-mentioned pod is seated on the loader in a direction corresponding to the above-mentioned second direction, and

[0028] The above EFEM chamber can rotate the above pod in the first direction from a direction corresponding to the second direction. Effects of the invention

[0029] As explained above, according to the present embodiment, since the internal space of the EFEM is maintained in a vacuum atmosphere, the wafer is not exposed to moisture in the atmosphere or molecular contaminants (AMC) in the air, so damage to the fine pattern or the occurrence of surface defects can be effectively prevented.

[0030] In addition, according to the present embodiment, since the EFEM itself has a structure that switches to a vacuum atmosphere, a conventional Load Lock module is not required, which simplifies the overall structure of the equipment. Consequently, the installation space of the equipment can be reduced, and the space utilization efficiency of the semiconductor process line can be maximized. This has the effect of improving the integration density of production facilities and ensuring flexibility during equipment maintenance and layout changes.

[0031] Furthermore, according to the present embodiment, since an aligner that performs wafer alignment is placed inside the EFEM chamber, there is no need to install a separate aligner chamber, and the overall volume of the equipment can be further reduced. This allows for minimizing interference between equipment while significantly increasing the layout efficiency and space utilization of the process line. In addition, since wafer alignment is performed under vacuum conditions, moisture adsorption or the attachment of contaminant particles due to exposure to the outside air is prevented, thereby improving alignment precision and process reliability.

[0032] In addition, according to the present embodiment, by performing nitrogen (N2) purging and vacuum exhaust in stages during the inflow process of the FOUP, moisture and contaminant gas can be removed quickly and stably from the internal space of the EFEM, and pressure imbalance or particle contamination that may occur during the vacuum transition process can be minimized. Brief explanation of the drawing

[0033] Figure 1 is a side view of a typical semiconductor process system. Figure 2 is a top view of a typical semiconductor process system. FIG. 3 is a top view of a semiconductor process system including a vacuum EFEM according to one embodiment. FIG. 4 is a side view of a vacuum EFEM according to one embodiment. FIG. 5 is a flowchart illustrating the process of moving a wafer in a vacuum EFEM according to one embodiment. FIG. 6 is a configuration diagram of an EFEM chamber according to one embodiment. FIG. 7 is a flowchart of nitrogen purging and vacuum exhaust according to one embodiment. FIG. 8 illustrates the process of a wafer moving through an aligner according to one embodiment. FIG. 9 illustrates the process of a wafer being moved to a loader after the process is completed, according to one embodiment. FIG. 10 is a drawing showing a first exemplary form in which a vacuum EFEM is arranged in a semiconductor process system according to one embodiment. FIG. 11 is a drawing showing a second exemplary form in which a vacuum EFEM is arranged in a semiconductor process system according to one embodiment. FIG. 12 is a drawing showing a third exemplary form in which a vacuum EFEM is arranged in a semiconductor process system according to one embodiment. Specific details for implementing the invention

[0034] Hereinafter, some embodiments of the present invention will be described in detail with reference to the exemplary drawings. It should be noted that in assigning reference numerals to the components of each drawing, the same components are given the same reference numeral whenever possible, even if they are shown in different drawings. Furthermore, in describing the present invention, if it is determined that a detailed description of related known components or functions could obscure the essence of the invention, such detailed description is omitted.

[0035] In addition, terms such as first, second, A, B, (a), (b), etc., may be used when describing the components of the present invention. These terms are intended only to distinguish the components from other components, and the essence, order, or sequence of the components is not limited by the terms. Where it is stated that a component is "connected," "combined," or "connected" to another component, it should be understood that the component may be directly connected or connected to the other component, but that another component may also be "connected," "combined," or "connected" between each component.

[0036] Figure 1 is a side view of a typical semiconductor process system, and Figure 2 is a top view of a typical semiconductor process system.

[0037] Referring to FIGS. 1 and 2, the semiconductor process system (1) may include an EFEM (10), a load lock (20), a VTM (30), and a process chamber (40), etc.

[0038] The EFEM (10) is a front module that performs the loading and unloading of wafers and may include an LPM (12, Load Port Module) and an EFEM chamber (13). The LPM (12) is a module that receives and places a FOUP (2, Front Opening Unified Pod) from an external transport device (OHT, Overhead Transport). A number of wafers (W) can be stored in the FOUP (2), and when the FOUP (2) is placed in the LPM (12), the front door of the FOUP (2) can be opened in conjunction with the first door (D1) between the LPM (12) and the EFEM chamber (13). Accordingly, a transfer robot placed in the EFEM chamber (13) can extract the wafers (W) inside the FOUP (2) one by one and deliver them to the inside of the process equipment.

[0039] The interior of the EFEM (10) is typically maintained at atmospheric pressure and configured to allow air from the cleanroom to circulate. That is, the atmosphere (temperature, pressure, and humidity) inside the EFEM is maintained at the same level as the cleanroom's control conditions. Since the relative humidity of the cleanroom is generally controlled to about 40%, the internal humidity of the EFEM chamber (13) is also maintained at about 40%.

[0040] The load lock (20) is positioned between the EFEM (10) and the VTM (30) and serves to buffer the pressure difference between the EFEM in an atmospheric pressure atmosphere and the VTM in a vacuum atmosphere. After the wafer (W) is transferred from the EFEM chamber (13) to the load lock (20), the inside of the load lock (20) is vacuum-evacuated and converted to a vacuum state, after which it can be transferred to the VTM (30).

[0041] The VTM (30) is connected to a plurality of process chambers (40) and is a vacuum transfer module that transfers wafers in a vacuum atmosphere, and a vacuum robot may be placed inside. Each process chamber (40) can perform various processes such as etching, deposition, heat treatment, and cleaning, and the central robot of the VTM (30) retrieves wafers (W) from the load lock (20) and distributes them to each process chamber (40).

[0042] In this structure, since the EFEM (10) is maintained at atmospheric pressure, the internal humidity is about 40%, which is the same as the humidity of the cleanroom. Therefore, there is a possibility that moisture in the air may be adsorbed or condensed on the wafer surface while the wafer (W) passes through the inside of the EFEM. In addition, since air from the cleanroom is continuously introduced into the inside of the EFEM, trace contaminants (AMC: Airborne Molecular Contamination) in the atmosphere or particles generated inside the equipment may adhere to the wafer surface. This causes defects such as short circuits between patterns, surface oxidation, and the formation of a contamination layer, and consequently, there is a problem of reduced process efficiency or reduced yield of the device.

[0043] To solve these problems, one embodiment provides vacuum EFEM technology in which the internal space of the EFEM chamber is maintained in a vacuum atmosphere.

[0044] FIG. 3 is a top view of a semiconductor process system including a vacuum EFEM according to one embodiment, and FIG. 4 is a side view of a vacuum EFEM according to one embodiment.

[0045] Referring to FIGS. 3 and 4, the semiconductor process system may include a vacuum EFEM (300), VTM (30), and process chamber (40), etc.

[0046] The process chamber (40) can be composed of various types of process modules for performing a semiconductor device manufacturing process, for example.

[0047] For example, an etching process chamber is used to remove a thin film on a wafer along a pattern formed after a photolithography process, and can operate using a dry etching method utilizing plasma. At this time, the inside of the process chamber is maintained in a high vacuum state of about 10^(-3) Torr or less, and the etching rate and selectivity are controlled by precisely controlling the concentration, pressure, and power density of the reaction gas.

[0048] As another example, a deposition process chamber is a device for forming insulating or metal films on a wafer surface and can be configured using one of the following methods: Chemical Vapor Deposition (CVD), Physical Vapor Deposition (PVD), or Atomic Layer Deposition (ALD). Since this deposition process requires nanoscale thin film thickness control, ensuring uniformity of vacuum levels and gas flow rates inside the chamber is critical.

[0049] The process chamber (40) may also include an annealing process chamber. This process is performed for purposes such as diffusion of impurities within the wafer, restoration of crystal defects, and removal of residual stress, and the internal temperature of the chamber may be raised from several hundred degrees to one thousand degrees (°C). The annealing chamber may form an oxidizing or non-oxidizing atmosphere by injecting an inert gas such as oxygen, nitrogen, or argon, and a plurality of heaters and thermal sensors are built in to ensure temperature uniformity.

[0050] In addition, the cleaning process chamber is a device for removing contaminants, organic residues, particles, etc. from the wafer surface and can be configured in a wet or dry manner. Wet cleaning cleans the surface using a chemical solution, while dry cleaning removes the contaminant layer using plasma or ozone (O3), etc. After the cleaning process, a vacuum drying step may follow to remove residual moisture.

[0051] In addition, the ion implantation process chamber, diffusion process chamber, CMP (Chemical Mechanical Polishing) pretreatment chamber, and packaging bonding chamber may be included, and in each chamber, the wafer is transferred to a vacuum state by VTM (30) and the process is performed sequentially.

[0052] Each of these process chambers (40) maintains a high vacuum state and is selectively opened and closed via a gate valve to prevent contact with the outside atmosphere. Therefore, it is important that the vacuum level of the VTM (30) is maintained stably, and that vacuum continuity between the EFEM (300) and the VTM (30) is ensured so that contamination of the wafer can be minimized.

[0053] The vacuum EFEM (300) may include a loader (310) and an EFEM chamber (330), etc.

[0054] The wafers (W) stored in the pod (2) are placed in an atmospheric pressure atmosphere when in the loader (310), and can be placed in a vacuum atmosphere when in the EFEM chamber (330). Also, the wafers (W) can be placed in a vacuum atmosphere in the VTM (30).

[0055] In one embodiment, the internal space of the EFEM chamber (330) and VTM (30) may be maintained in a vacuum atmosphere, wherein the vacuum atmosphere may be in a pressure state of 10^(-1) Torr to 10^(-3) Torr. And, the internal space of the EFEM chamber (330) and VTM (30) may have substantially the same level of pressure, but depending on the embodiment, may have a slightly different pressure magnitude within the aforementioned pressure range.

[0056] The pod (2) supplied via OHT (Overhead Hoist Transport) can be lowered into the loader (310) in an atmospheric pressure atmosphere.

[0057] The OHT is an automatic conveying device installed on the ceiling of a semiconductor manufacturing line, capable of automatically supplying or retrieving pods (2) to multiple process equipment while traveling along the OHT rail. The OHT rail is generally fixed to the ceiling structure of a cleanroom and is installed orthogonally in the horizontal (X-axis) and vertical (Y-axis) directions corresponding to the arrangement direction of the process equipment. Accordingly, the pods (2) transported by the OHT move in a straight line along the direction of travel of this rail and approach downward from the loader (310) position on the upper part of the equipment to be settled.

[0058] At this time, the driving direction of the OHT is generally set to be the same as or perpendicular to the arrangement direction of the entire process line, and the front part of the process equipment is usually arranged parallel to or perpendicular to the movement path of the OHT. However, in this embodiment, the side of the EFEM chamber (320) may be arranged so as not to be parallel to the movement path of the OHT. That is, by having a structure in which the driving direction of the OHT and the direction in which the pod moves to the EFEM chamber are angled at a certain angle when viewed in a planar view, the pod (2) can be introduced into the EFEM chamber (320) through rotation or direction change operation after being lowered from the OHT to the loader (310).

[0059] This OHT-EFEM arrangement structure has the advantage of increasing the placement efficiency of the equipment and minimizing interference between the equipment within a limited cleanroom space. In addition, the rotational or non-orthogonal transfer structure of the pod (2) allows the installation direction of the equipment to be flexibly adjusted, thereby reducing placement constraints when reconfiguring the process line. Related examples will be described later with reference to FIGS. 11 and 12.

[0060] The pod (2) can be placed on a sliding moving device (412) that is positioned on the loader (310). The sliding moving device (412) can slide into the internal space of the EFEM chamber (330) by means of a rail (414), etc.

[0061] A first valve (322) may be positioned between the loader (310) and the EFEM chamber (330). When the first valve (322) is closed, the internal space of the EFEM chamber (330) may be isolated from the loader (310) or the cleanroom space, and when the first valve (322) is open, the internal space of the EFEM chamber (330) may be connected to the loader (310). The first valve (322) may be opened or closed as the first gate (425) embedded in the first valve (322) moves.

[0062] When the first valve (322) is opened while the pod (2) is seated on the loader (310), the sliding moving device (412) can slide into the internal space of the EFEM chamber (330). At this time, the pod (2) seated on the upper side of the sliding moving device (412) can also move together into the internal space of the EFEM chamber (330).

[0063] Since the EFEM chamber (330) is positioned on the side of the loader (310) between the loader (310) and the VTM (30), the pod (2) can be introduced into and seated in the EFEM chamber (330) from the side upon opening of the first valve (322).

[0064] When the pod (2) is seated inside the EFEM chamber (330), the first valve (322) is closed and the internal space of the EFEM chamber (330) can be switched to a vacuum atmosphere.

[0065] After the pod (2) is placed inside the EFEM chamber (330), it can be moved up, down, left, and right as needed by the support structure (421). For example, the pod (2) can be moved up and down to match the height of the vacuum robot (35) placed in the VTM (30).

[0066] When the first valve (322) is closed and the internal space of the EFEM chamber (330) is switched to a vacuum atmosphere, the second valve (332) is opened, and a connecting passage can be formed between the EFEM chamber (330) and the VTM (30).

[0067] When the EFEM chamber (330) and VTM (30) are connected by opening the second valve (332), a vacuum robot (35) placed in VTM (30) can retrieve wafers (W) stored in the pod (2) in a vacuum atmosphere.

[0068] The wafers (W) that have finished processing are stored back into the pod (2), and when all processing on the wafers (W) stored in the pod (2) is finished, the second valve (332) can be closed again.

[0069] When the internal space of the EFEM chamber (330) is cut off from the outside due to the closing of the second valve (332), the EFEM chamber (330) can be switched back to an atmospheric pressure atmosphere.

[0070] After switching to an atmospheric pressure atmosphere, the first valve (322) is opened, and the pod (2) can be discharged laterally into the loader (310).

[0071] An aligner (350) can be placed in the internal space of the EFEM chamber (330).

[0072] The aligner (350) can be placed on the upper side of the space where the pod (2) is seated.

[0073] A vacuum robot (35) placed in the VTM (30) can extract wafers (W) stored in the pod (2) and transfer them to the process chamber while the EFEM chamber (330) and the VTM (30) are connected. At this time, the vacuum robot (350) can extract the wafer (W) from the pod (2) and then move the wafer (W) to the aligner (350). Then, once the wafer (W) is aligned in the aligner (350), the wafer (W) can then be moved to the process chamber.

[0074] FIG. 5 is a flowchart illustrating the process of moving a wafer in a vacuum EFEM according to one embodiment.

[0075] Referring to FIG. 5, the pod can be supplied to the loader through the OHT (S500). The pod moving through the OHT in the upper space of the cleanroom can be placed on the loader while moving downward from the upper side of the loader.

[0076] When the pod is seated on the loader, the first valve positioned between the loader and the EFEM chamber can be opened (S502).

[0077] And, the pod can be laterally introduced from the loader into the EFEM chamber (S504).

[0078] After the pod is seated in the EFEM chamber, the first valve is closed and the internal space of the EFEM chamber can be isolated from the outside. In this isolated state, the internal space of the EFEM chamber can be converted to a vacuum atmosphere through vacuum evacuation (S506).

[0079] After the internal space of the EFEM chamber is switched to a vacuum atmosphere, the second valve placed between the EFEM chamber and the VTM can be opened (S508).

[0080] And, a vacuum robot placed in the VTM can retrieve wafers stored in a pod located in the EFEM chamber one by one and align the wafers through an aligner (S510), and can transfer the aligned wafers directly to the VTM without passing through a load lock (S512).

[0081] There is no robot in the EFEM chamber, and a vacuum robot deployed in the VTM can directly retrieve wafers from the pod located inside the EFEM chamber.

[0082] A vacuum robot is a transfer robot that operates in a vacuum atmosphere and includes multiple rotation axes and an extendable arm structure, enabling precise extraction and transfer of wafers.

[0083] The end of the arm of the vacuum robot may be equipped with a vacuum suction pad or an electrostatic chuck gripper to stably support the wafer, and is controlled to precisely access the internal slot of the FOUP based on the center position and height information of the wafer. When the gate valve between the EFEM chamber (vacuum state) and the VTM is opened, this vacuum robot may enter the EFEM chamber partially or fully to sequentially extract wafers from the FOUP and then transfer them to each process chamber.

[0084] At this time, the operation of the vacuum robot can be performed under low acceleration and low vibration conditions to prevent wafer damage or particle contamination, and the robot's movement path and arm deployment angle can be automatically adjusted according to the position of the FOUP, the internal dimensions of the EFEM chamber, the opening range of the gate valve, etc. In addition, the vacuum robot is configured to operate only when the air pressure of the EFEM chamber and the VTM is uniformly matched to each other, thereby preventing fine particle scattering or contamination caused by the pressure difference between the two spaces.

[0085] Looking at the wafer movement process, the wafer moves from the OHT to the loader while stored in the pod. Then, when moving from the loader to the EFEM chamber, it moves in the same state as being stored in the pod. Afterward, when moving from the EFEM chamber to the process chamber, it moves one wafer at a time.

[0086] This method differs from a general semiconductor process method in which wafers move one by one, passing from an atmospheric pressure atmosphere to a vacuum atmosphere. In the general semiconductor process method described with reference to FIGS. 1 and 2, when wafers move one by one, they are exposed to an atmospheric pressure atmosphere within the EFEM and then to a vacuum atmosphere after the load lock. However, according to the method of one embodiment, the wafer is moved to an EFEM chamber in a vacuum atmosphere while housed in a pod, and thereafter, when wafers move one by one, they are continuously exposed only to a vacuum atmosphere.

[0087] Due to this difference in method, the humidity and AMC problems that appear in general semiconductor process methods do not appear in one embodiment.

[0088] FIG. 6 is a configuration diagram of an EFEM chamber according to one embodiment.

[0089] Referring to FIG. 6, an aligner (350), a nitrogen purging device (610), and a vacuum exhaust device (620) may be installed in the EFEM chamber (330). Alternatively, the nitrogen purging device (610) and / or the vacuum exhaust device (620) may be installed outside the EFEM chamber (330) and connected to the EFEM chamber (330) through piping.

[0090] With both the first valve positioned on the loader side and the second valve (332) positioned on the VTM (30) side closed, the internal space of the EFEM chamber (330) can be switched to a vacuum atmosphere. At this time, the vacuum exhaust device (620) can vacuum the internal space of the EFEM chamber (330).

[0091] The vacuum exhaust device (620) can obtain a measurement of the internal pressure of the EFEM chamber (330) and the VTM (30), and based on this measurement, the vacuum exhaust device (620) can perform vacuum exhaust until the pressure of the EFEM chamber (330) approaches the pressure of the VTM (30) within a certain range. Then, when the pressure of the EFEM chamber (330) approaches the pressure of the VTM (30) within a certain range, the second valve (332) can be opened.

[0092] The door (D) of the pod (2) may be opened before the vacuum exhaust device (620) starts vacuum exhaust. In general semiconductor process equipment, the door of the pod may be opened together with the second valve, but in one embodiment, the door (D) of the pod (2) may be opened first with the second valve (332) closed for vacuum exhaust.

[0093] In terms of sequence, vacuum exhaust can be started after the door (D) of the pod (2) is opened, and the second valve (332) can be opened after the vacuum exhaust is finished.

[0094] Nitrogen purging can be performed before vacuum evacuation.

[0095] The nitrogen purging device (610) can purge nitrogen (N2) into the internal space of the EFEM chamber (330) while both the first valve and the second valve are closed. At this time, the door (D) of the pod (2) can be opened.

[0096] In sequence, the pod (2) is introduced from the loader sideways, and after the first valve is closed, nitrogen can be purged into the internal space of the EFEM chamber (330). The door of the pod (2) can be opened when nitrogen is purged into the internal space of the EFEM chamber (330), or after nitrogen is purged, or before nitrogen is purged. Accordingly, nitrogen can remove contaminants affecting the wafers (W) of the pod (2).

[0097] After the nitrogen purging, the vacuum exhaust device (620) can vacuum the internal space of the EFEM chamber (330). By performing the nitrogen purging and vacuum exhaust in stages during the inflow process of the pod (2), moisture and contaminant gases can be removed quickly and stably from the internal space of the EFEM chamber (330), and pressure imbalance or particle contamination that may occur during the vacuum transition process can be minimized.

[0098] The aligner (350) can be placed on the upper side of the pod (2) being seated. Since the pod (2) is introduced laterally through the sliding moving device (412), it does not interfere with the aligner (350) placed on the upper side.

[0099] The aligner (350) may include a rotary stage (352) and an optical sensor (354). The rotary stage (352) may be formed into a disc-shaped structure on which a wafer (W) is placed and may be driven to rotate by a motor. A vacuum suction pad or an electrostatic chuck may be provided on the upper surface of the rotary stage (352) to stably hold the wafer (W). This allows the wafer (W) to be fixed without shaking even during rotation, enabling precise alignment.

[0100] An optical sensor (354) is positioned on the upper or lateral side of a rotating stage (352) to detect the location of a notch or flat by scanning the outer edge of a rotating wafer (W). The optical sensor (354) may be composed of a reflective optical sensor or a laser displacement sensor and calculates a reference angle by recognizing the outer contour line along the rotational trajectory of the wafer (W). The rotating stage (352) is automatically rotated based on the reference angle data transmitted from the optical sensor (354) to align the reference direction of the wafer (W).

[0101] A wafer (W) that has been aligned can be picked up from a rotating stage (352) by a vacuum robot and transferred to a process chamber (40). Since the wafer alignment process is performed in a vacuum atmosphere within the EFEM chamber (330), moisture or fine contaminant particles from the outside air can be effectively prevented from adhering to the wafer surface. As a result, the alignment precision of the wafer is improved, and the possibility of alignment errors or defects that may occur in subsequent process steps such as exposure, etching, and deposition can be minimized.

[0102] In addition, since the aligner (350) is integrally placed inside the EFEM chamber (330), there is no need to install a separate aligner chamber, and the overall structure of the equipment is simplified, thereby increasing the efficiency of space utilization within the process line. Accordingly, this has the effect of reducing the equipment installation area, improving maintenance accessibility, and enhancing the layout flexibility of the entire system.

[0103] FIG. 7 is a flowchart of nitrogen purging and vacuum exhaust according to one embodiment.

[0104] Referring to FIG. 7, when the pod is introduced into and settled into the EFEM chamber, the door of the pod can be opened first (S700).

[0105] And, with the door of the pod open, the nitrogen purge device can supply nitrogen into the internal space of the EFEM chamber (S702).

[0106] After the nitrogen purging is completed, the vacuum exhaust device can start vacuuming the internal space of the EFEM chamber (S704).

[0107] While performing vacuum evacuation, the vacuum evacuation device can check the pressure of the VTM (S706) and check the pressure of the EFEM chamber (S708).

[0108] In addition, the vacuum exhaust device can perform vacuum exhaust until the air pressure of the EFEM chamber approaches the air pressure of the VTM within a certain range (S710).

[0109] And, when vacuum evacuation is completed and the pressure of the EFEM chamber and the pressure of the VTM become substantially equal, the second valve can be opened (S712).

[0110] FIG. 8 illustrates the process of a wafer moving through an aligner according to one embodiment.

[0111] Referring to FIGS. 3 and FIGS. 8, the wafer can be moved from the OHT to the loader while stored in the pod (S800).

[0112] Then, the wafer can be moved to the EFEM chamber while still in the pod (S802). During this moving process or the initial process of being placed in the pod, the alignment direction of the wafer may differ from the process direction in the process chamber.

[0113] To align it, the wafer can be moved to an aligner (350) placed in the vacuum atmosphere space of the EFEM chamber (S804).

[0114] Then, the wafer can be transferred to the process chamber (40) after being aligned in the aligner (350) (S806). The transfer to the aligner can be performed by a vacuum robot (35) placed in the VTM (30).

[0115] FIG. 9 illustrates the process of a wafer being moved to a loader after the process is completed, according to one embodiment.

[0116] Referring to FIG. 9, the wafer can be moved between process chambers via a vacuum robot, and the process on the wafer can be performed (S900).

[0117] After the process is completed, the wafer can be moved from the VTM to the pod inside the EFEM chamber (S902).

[0118] After each wafer is stored in the pod in this way, the second valve placed between the EFEM chamber and the VTM is closed, so that the EFEM chamber can be isolated from the outside (S906).

[0119] Afterwards, nitrogen can be purged into the internal space of the EFEM chamber (S908).

[0120] And, when the air pressure of the EFEM chamber rises to a certain level, the door of the pod is closed (S910), and the first valve is opened so that the pod can move laterally toward the loader (S912).

[0121] FIG. 10 is a drawing showing a first exemplary form in which a vacuum EFEM is arranged in a semiconductor process system according to one embodiment.

[0122] Referring to FIG. 10, when viewed planar from the top to the bottom, the direction formed by the loader (310) and the EFEM chamber (330) in the vacuum EFEM (300) may be a direction perpendicular to the OHT rail (3). The pod (2) moves from the loader (310) to the EFEM chamber (330) in the vacuum EFEM (300) along the direction formed by the loader (310) and the EFEM chamber (330) (first direction).

[0123] Meanwhile, the pod (2) can approach the loader (310) while moving along the arrangement direction (second direction) of the OHT rail (3). Then, the pod (2) can stop at the upper side of the loader (310) and then be lowered onto the loader (310). In this arrangement, the first direction and the second direction may be vertical directions.

[0124] In one embodiment, the loader (310) and the EFEM chamber (330) form a pair and can be connected to one side of the VTM (30). In this case, if the VTM (30) has a polygonal shape, the direction in which the pair formed by the loader (310) and the EFEM chamber (330) is connected to the VTM (30) may not be perpendicular or horizontal to the direction of the OHT rail (3).

[0125] FIG. 11 is a drawing showing a second exemplary form in which a vacuum EFEM is arranged in a semiconductor process system according to one embodiment.

[0126] Referring to FIG. 11, the VTM (30) may have a polygonal shape, and vacuum EFEMs may be connected to two corners of the polygon formed by the VTM (30). Here, the vacuum EFEM connected to the first corner is called the first vacuum EFEM (1300a), and the vacuum EFEM connected to the second corner is called the second vacuum EFEM (1300b).

[0127] The first vacuum EFEM (1300a) and the second vacuum EFEM (1300b) may be arranged in a direction that is not perpendicular or horizontal to the OHT rail (3). In other words, the direction formed by the first loader (1310a) and the first EFEM chamber (1330a) in the first vacuum EFEM (1300a) may be a direction that is not perpendicular or horizontal to the direction in which the pod (2) moves along the OHT rail (3), and the direction formed by the second loader (1310b) and the second EFEM chamber (1330b) in the second vacuum EFEM (1300b) may be a direction that is not perpendicular or horizontal to the direction in which the pod (2) moves along the OHT rail (3).

[0128] At this time, the first loader (1310a) and the second loader (1310b) can be positioned at a location that overlaps with the path of the OHT rail (3) when viewed from above.

[0129] The pods (2) can be moved along the OHT rail (3) and alternately placed on the first loader (1310a) and the second loader (1310b).

[0130] Meanwhile, in this structure, since the direction of travel of the OHT rail (3) (second direction) and the direction formed by the loader and the EFEM chamber (first direction) are not vertical or horizontal, the loader (1310a, 1310b) can move the seated pod (2) to the first direction from the direction corresponding to the second direction, and then move it to the EFEM chamber (1330a, 1330b).

[0131] FIG. 12 is a drawing showing a third exemplary form in which a vacuum EFEM is arranged in a semiconductor process system according to one embodiment.

[0132] Referring to FIG. 12, the VTM (30) may have a polygonal shape, and vacuum EFEMs may be connected to two corners of the polygon formed by the VTM (30). Here, the vacuum EFEM connected to the first corner is called the first vacuum EFEM (1400a), and the vacuum EFEM connected to the second corner is called the second vacuum EFEM (1400b).

[0133] The first vacuum EFEM (1400a) and the second vacuum EFEM (1400b) may be arranged in a direction that is not perpendicular or horizontal to the OHT rail (3). In other words, the direction formed by the first loader (1410a) and the first EFEM chamber (1430a) in the first vacuum EFEM (1400a) may be a direction that is not perpendicular or horizontal to the direction in which the pod (2) moves along the OHT rail (3), and the direction formed by the second loader (1410b) and the second EFEM chamber (1430b) in the second vacuum EFEM (1400b) may be a direction that is not perpendicular or horizontal to the direction in which the pod (2) moves along the OHT rail (3).

[0134] At this time, the first loader (1410a) and the second loader (1410b) can be positioned at a location that overlaps with the path of the OHT rail (3) when viewed from above.

[0135] The pods (2) can be moved along the OHT rail (3) and alternately placed on the first loader (1410a) and the second loader (1410b). Then, the pods (2) can be moved from the loaders (1410a, 1410b) to the EFEM chambers (1430a, 1430b).

[0136] Meanwhile, in this structure, since the direction of travel of the OHT rail (3) (second direction) and the direction formed by the loader and the EFEM chamber (first direction) are not vertical or horizontal, the EFEM chamber (1410a, 1410b) can rotate the seated pod (2) in the first direction from the direction corresponding to the second direction.

[0137] As explained above, according to the present embodiment, since the internal space of the EFEM is maintained in a vacuum atmosphere, the wafer is not exposed to moisture in the atmosphere or molecular contaminants (AMC) in the air, so damage to the fine pattern or the occurrence of surface defects can be effectively prevented.

[0138] In addition, according to the present embodiment, since the EFEM itself has a structure that switches to a vacuum atmosphere, a conventional Load Lock module is not required, which simplifies the overall structure of the equipment. Consequently, the installation space of the equipment can be reduced, and the space utilization efficiency of the semiconductor process line can be maximized. This has the effect of improving the integration density of production facilities and ensuring flexibility during equipment maintenance and layout changes.

[0139] Furthermore, according to the present embodiment, since an aligner that performs wafer alignment is placed inside the EFEM chamber, there is no need to install a separate aligner chamber, and the overall volume of the equipment can be further reduced. This allows for minimizing interference between equipment while significantly increasing the layout efficiency and space utilization of the process line. In addition, since wafer alignment is performed under vacuum conditions, moisture adsorption or the attachment of contaminant particles due to exposure to the outside air is prevented, thereby improving alignment precision and process reliability.

[0140] In addition, according to the present embodiment, by performing nitrogen (N2) purging and vacuum exhaust in stages during the inflow process of the FOUP, moisture and contaminant gas can be removed quickly and stably from the internal space of the EFEM, and pressure imbalance or particle contamination that may occur during the vacuum transition process can be minimized.

[0141] Terms such as "include," "compose," or "have" as described above, unless specifically stated otherwise, mean that the relevant component may be inherent; therefore, they should be interpreted as allowing for the inclusion of additional components rather than excluding them. All terms, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains, unless otherwise defined. Commonly used terms, such as those defined in advance, should be interpreted in accordance with their meaning in the context of the relevant technology and should not be interpreted in an ideal or overly formal sense unless explicitly defined in the present invention.

[0142] The foregoing description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are intended to explain, not limit, the technical concept of the present invention, and the scope of the technical concept of the present invention is not limited by these embodiments. The scope of protection of the present invention shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of the present invention. Explanation of the symbols

[0143] Semiconductor Process System: 1 EFEM : 10 Loadlock : 20 VTM : 30 Process Chamber: 40 LPM : 12 EFEM chamber: 13 Pfft : 2 Vacuum EFEM: 300 Loader: 310 EFEM Chamber: 330 OHT Rail: 3 EFEM Chamber: 320 Sliding moving device: 412 Rail: 414 Valve 1: 322 Gate 1: 425 Valve 2: 332 Vacuum Robot: 35 Support structure: 421 Aligner: 350 Nitrogen purging device: 610 Vacuum exhaust system: 620

Claims

Claim 1 A vacuum EFEM comprising: a loader in which a Front Opening Unified Pod (FOUP) is lowered in an atmospheric pressure atmosphere; and an Equipment Front End Module (EFEM) chamber disposed on the side of the loader between a Vacuum Transfer Module (VTM) and the loader, wherein the FOUP is introduced and seated laterally upon opening of a first valve, the internal space is converted to a vacuum atmosphere after closing of the first valve, and an aligner is disposed on the upper side of the space where the FOUP is seated. Claim 2 A vacuum EFEM according to claim 1, wherein a vacuum robot disposed within the VTM while the EFEM chamber and the VTM are in communication extracts wafers stored in the pod and transfers them to a process chamber. Claim 3 In paragraph 2, the vacuum robot extracts a wafer from the pod, aligns the wafer through the aligner, and then moves it to the process chamber, vacuum EFEM. Claim 4 A vacuum EFEM according to claim 1, wherein the pod seated on the loader slides into the internal space of the EFEM chamber by means of a sliding moving device positioned on the lower side. Claim 5 In claim 1, the vacuum EFEM chamber is such that the pod is introduced laterally and switched to a vacuum atmosphere after the first valve is closed, and after all processes for the wafers contained in the pod are completed, the second valve disposed between the VTM is closed and switched back to an atmospheric pressure atmosphere, and after switching to an atmospheric pressure atmosphere, the first valve is opened to laterally discharge the pod to the loader.

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