Plasma etching device

Abstract

A plasma etching apparatus includes a chamber, an inductance coil above the chamber, a plasma power source electrically connected to the inductance coil, a pump in gas communication with the chamber and laterally spaced apart from the inductance coil, and a pneumatic purge device. The pneumatic purification device comprises a sealing cover. The shape of the sealing cover is matched with an opening defined by a top rim of the pump.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a plasma etching apparatus, and more particularly to a plasma etching apparatus with a purge function. BACKGROUND

[0002] Dry etching processes, including plasma etching, are a technology in the field of semiconductor manufacturing and microfabrication. Unlike wet etching, which uses liquid chemicals to remove material from a substrate, dry etching uses a plasma state of a gas to achieve material removal. This process helps to produce complex patterns and features on semiconductor wafers, which is the basis of integrated circuit production. SUMMARY

[0003] In some embodiments, a plasma etching apparatus includes a chamber, an inductive coil above the chamber, a plasma power source electrically connected to the inductive coil, a pump in gas communication with the chamber and laterally spaced apart from the inductive coil, and a pneumatic purge apparatus. The pneumatic purge apparatus includes a seal cover. The seal cover is shaped to match an opening defined by a top rim of the pump.

[0004] In some embodiments, a plasma etching apparatus includes an upper chamber, a plasma power source electrically connected to an inductive coil positioned on the upper chamber, a lower chamber connected to a first region of the upper chamber, a wafer chuck in the lower chamber, and a pump connected to a second region of the upper chamber. The pump is separated from the lower chamber by a non-zero horizontal distance. The plasma etching apparatus further includes a pneumatic purge apparatus including a seal cover, a first O-ring, and a gas inlet tube. The seal cover has a gas passage extending through a top surface of the seal cover and a bottom surface of the seal cover, the first O-ring is around a peripheral wall of the seal cover and the first O-ring is in airtight engagement with a ring-shaped top rim of the pump. The gas inlet tube is above the bottom surface of the seal cover. The gas inlet tube is upstream of the gas passage of the seal cover.

[0005] In some embodiments, a plasma etching apparatus includes an upper chamber, a plasma power source electrically connected to an inductive coil positioned on the upper chamber, a lower chamber connected to a first region of the upper chamber, a wafer chuck in the lower chamber, and a pump connected to a second region of the upper chamber. The pump is separated from the lower chamber by a non-zero horizontal distance. The plasma etching apparatus further includes a pneumatic purge apparatus including a seal cover, a gas inlet tube, and two handles. The seal cover has a gas passage extending through a top surface of the seal cover and a bottom surface of the seal cover, the seal cover is shaped to match an opening defined by a top rim of the pump. The gas inlet tube is above the bottom surface of the seal cover. The gas inlet tube is upstream of the gas passage of the seal cover. The two handles are at opposite sides of the gas inlet tube. BRIEF DESCRIPTION OF DRAWINGS

[0006] Aspects of the present disclosure are illustrated by way of example, and not limitation, in the figures of the accompanying drawings in which: Figure OneThe present disclosure is best understood from the following detailed description when read in conjunction with the accompanying drawings. It is noted that the various features are not drawn to scale. In fact, the dimensions of the various features can be arbitrarily increased or decreased for clarity of discussion.

[0007] Figure 1 is a flowchart illustrating an exemplary process of plasma etching device operation and maintenance, in accordance with some embodiments of the present disclosure;

[0008] Figures 2 to 4A is a schematic side view of a plasma etching device, in accordance with some embodiments of the present disclosure, illustrating various stages of a plasma etching operation;

[0009] Figure 4B and Figure 4C are enlarged cross-sectional views of a substrate W, respectively illustrating initial and final stages of a plasma etching operation, in accordance with some embodiments of the present disclosure;

[0010] Figure 5 is a schematic side view of a plasma etching device, in accordance with some embodiments of the present disclosure, illustrating a wafer-less auto clean (WAC) operation;

[0011] Figure 6A is a schematic side view of a plasma etching device, in accordance with some embodiments of the present disclosure, illustrating an initial stage of a pump purge operation;

[0012] Figure 6B is a three-dimensional view of a pneumatic purge device, in accordance with some embodiments of the present disclosure;

[0013] Figure 6C is a top view of a turbomolecular pump, in accordance with some embodiments of the present disclosure;

[0014] Figure 7 is a schematic side view of a plasma etching device, in accordance with some embodiments of the present disclosure, illustrating a subsequent stage of a pump purge operation;

[0015] Figure 8A illustrates a bottom view of a pneumatic purge device, in accordance with some embodiments of the present disclosure;

[0016] Figure 8B illustrates an enlarged cross-sectional view of a region where a pneumatic purge device is placed onto a turbomolecular pump, in accordance with some embodiments of the present disclosure;

[0017] Figure 9A illustrates a bottom view of another pneumatic purge device, in accordance with some embodiments of the present disclosure;

[0018] Figure 9BFIG. 6 illustrates a cross-sectional view of a gas ballast valve according to some embodiments of the present disclosure.

[0019] SYMBOL DESCRIPTION

[0020] 100: process

[0021] 102-106: operations

[0022] 200: plasma etching apparatus

[0023] 202: upper chamber

[0024] 204: ceramic dome

[0025] 206: lower chamber

[0026] 208: ESC cathode / wafer chuck

[0027] 210: gas nozzle

[0028] 212: throttle valve

[0029] 214: wafer load port

[0030] 216: wafer lift

[0031] 218: inductive coil

[0032] 220: RF source

[0033] 222: matching network

[0034] 224: inductively coupled plasma power supply

[0035] 230: turbomolecular pump

[0036] 231: top rim

[0037] 232: rotor blades

[0038] 233: perforated cover

[0039] 234: interior space

[0040] 235: opening

[0041] 236: rotor

[0042] 238: stationary stator blades

[0043] 240: roughing pump

[0044] 242: exhaust conduit

[0045] 244: three-way valve

[0046] 250: purge pump

[0047] 260: controller

[0048] 302: plasma

[0049] 304: ions

[0050] 306: byproduct particles

[0051] 400: pneumatic purifier

[0052] 400a: pneumatic purifier

[0053] 402: gas inlet tube

[0054] 404: seal cap

[0055] 406: handle

[0056] 408: dual seal o-ring

[0057] 410: stand

[0058] 500: source of purifying gas

[0059] 510: controller

[0060] 902: etched target layer

[0061] 904: patterned mask layer

[0062] 2332: opening

[0063] 4022: gas inlet nozzle

[0064] 4024: flexible hose

[0065] 4026: gas passage

[0066] 4028: gas outlet

[0067] 4042: manifold

[0068] 4044: inlet port

[0069] 4046: main passage

[0070] 4048: outlet port

[0071] 4062: main portion

[0072] 4064: support portion

[0073] A1-A2: arrow

[0074] D1: horizontal distance

[0075] P1: inlet port

[0076] P2-P3: exit port

[0077] S1-S7: control signal

[0078] W: substrate DETAILED DESCRIPTION

[0079] The following disclosure provides many different embodiments, or examples, for implementing different characteristics of the provided subject matter. Specific examples of components and configurations are described below to simplify the present disclosure. These are, of course, merely examples and are in no way limiting of the scope of the present disclosure. For example, in the following description, the formation of a first feature over or on a second feature can include embodiments in which the first feature is formed directly on the second feature, as well as embodiments in which additional features can be formed between the first and second features such that the first and second features are not in direct contact. In addition, the present disclosure can make reference to various examples of components and / or configurations. These examples are intended to be illustrative of aspects of the present disclosure and do not limit the scope of the present disclosure. The disclosure recited herein is directed to any one of the various examples described.

[0080] Further, spatially relative terms, such as "beneath", "below", "lower", "above", "upper", and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. The devices can be otherwise oriented (rotated 230 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. As used herein, "about", "approximately", or "substantially" can generally mean within 20 percent, or within 10 percent, or within 5 percent of a given value or range. Values given herein are approximate, meaning that the term "about", "approximately", or "substantially" can be inferred if not expressly stated. However, those of ordinary skill in the art will recognize that the values or ranges mentioned throughout the specification are merely examples and can decrease or change as integrated circuits scale in size.

[0081] Semiconductor processing equipment, such as plasma etching systems, plasma-enhanced chemical vapor deposition (PE-CVD) systems, and sputtering systems, are widely used throughout the production of integrated circuits (ICs). Such semiconductor processing equipment can include a processing chamber that facilitates containing processes that are often reactive performed by the equipment. As a result of these processes, byproducts can form in the semiconductor processing equipment, leading to degradation of performance and / or contamination of the equipment, which can result in decreased IC yield.

[0082] To maintain equipment efficiency and improve IC yield, periodic cleaning is performed to remove byproduct accumulation. For example, during plasma etching, a workpiece is placed into a processing chamber. The workpiece typically includes a patterned photoresist layer over an etch target layer, such as a dielectric layer (e.g., silicon oxide, silicon nitride) or a metal layer (e.g., copper, titanium nitride). A plasma etching device generates a plasma within the processing chamber to selectively etch the target layer. During etching, non-volatile byproducts are generated that accumulate on various components of the device, such as the chamber sidewalls and the vanes of a vacuum pump, such as a turbo molecular pump (TMP) used to evacuate the chamber and maintain a vacuum environment.

[0083] When processing the workpiece or subsequent workpieces, these byproduct particles can dislodge from the chamber sidewalls or pump vanes and contaminate the workpiece, potentially leading to IC defects. To mitigate this, a wafer-less auto clean (WAC) process is employed to remove byproduct particles from the chamber sidewalls. However, due to the limited reach of the plasma, WAC is less effective at cleaning the pump vanes.

[0084] To address this limitation, the disclosure provides, in various embodiments, a method and apparatus that effectively removes byproduct particles from the pump vanes. The method includes using a pneumatic purging device to purge the interior of the vacuum pump, in addition to the WAC process that cleans the chamber sidewalls using plasma. By blowing a gas stream into the interior of the vacuum pump, byproduct particles are effectively removed from the pump vanes, thereby improving the overall cleanliness of the etching device.

[0085] Figure 1 is a flowchart illustrating an exemplary process 100 for plasma etching device operation and maintenance, in accordance with some embodiments of the disclosure. At operation 102, a wafer is subjected to plasma etching using a plasma etching device, which will be described in more detail with reference to FIG. 1. Figures 2 to 4CA detailed description follows. In operation 104, after one or more plasma etching operations are completed on one or more wafers, a wafer-less auto clean (WAC) operation is performed within the plasma etching apparatus, as shown in Figure 5 Figures 6A to 9B A detailed description follows. These operations 102, 104, and 106 can collectively constitute a loop process, which can be repeated to perform plasma etching on a large number of wafers with a minimized impact of byproduct particles on yield.

[0086] Figure 2 is a schematic side view of a plasma etching apparatus 200, illustrating the initial step of the plasma etching operation 102. The plasma etching apparatus 200 includes an upper chamber 202 having a ceramic dome 204, and a lower chamber 206. The lower chamber 206 includes an electrostatic chuck (ESC) cathode 208, also referred to as a wafer chuck 208. Gases are introduced into the chamber through gas nozzles 210 for uniform gas distribution. Chamber pressure is controlled by a throttle valve 212. During processing, a substrate W is loaded into the lower chamber 206 via a wafer load port 214. Electrostatic charges generated on the surface of the electrostatic chuck (ESC) cathode 208 hold the substrate W in place by applying a DC voltage to a conductive layer beneath a dielectric film on the chuck surface (not shown). The ESC cathode 208 and the substrate W are then raised (as shown by arrow Al) by a wafer lift 216 and brought into a seal against the upper chamber 202 in a position for processing. Etching gases are introduced into the upper chamber 202 through ceramic gas injection nozzles 210. The plasma etching apparatus 200 uses an inductively coupled plasma power supply 224 operating at about 1-3 MHz, which is connected to an inductive coil 218 for generating and maintaining a high-density plasma. The wafer is biased by an RF source 220 and a matching network 222 operating in the range of 50 kHz to 15 MHz, more specifically, in the range of 100 kHz to 3 MHz. The power to the plasma power supply 224 and the substrate biasing RF source 220 are controlled by a controller 260.

[0087] ​The upper chamber 202 and the lower chamber 206 are in gaseous communication with a throttle valve 212. The throttle valve 212 is located above and in gaseous communication with a turbomolecular pump 230, which is in gaseous communication with a roughing pump 240 through an exhaust conduit 242. The turbomolecular pump 230 and the roughing pump 240 are vacuum pumps that collectively function as a vacuum source designed to achieve target pressure conditions within the chambers 202, 206 for a plasma etching process. In some embodiments, the lower chamber 206 is connected to a first zone at the bottom side of the upper chamber 202, and the turbomolecular pump 230 is connected to a second zone at the bottom side of the upper chamber 202. The turbomolecular pump 230 is separated from the lower chamber 206 by a non-zero horizontal distance.

[0088] In some embodiments, the turbomolecular pump 230 is a high vacuum pump that utilizes rapidly rotating blades 232 to impart kinetic energy to gas molecules, effectively compressing and transporting the gas molecules out of the chambers 202, 206 to achieve lower pressures. The turbomolecular pump 230 is well suited for achieving high vacuum conditions operating in the range of about 10 -3 to 10 -9 Torr. The turbomolecular pump 230 operates at high rotational speeds, such as over 20,000 revolutions per minute (RPM), allowing for efficient handling of large amounts of gas.

[0089] The roughing pump 240, interchangeably referred to as a backing dry pump, assists the turbomolecular pump 230 by managing initial and intermediate vacuum levels, typically from atmospheric pressure down to about 10 -3 Torr. In some embodiments, the roughing pump 240 is a mechanical pump, such as a lobe or scroll pump, that uses a positive displacement mechanism to evacuate gas to an intermediate vacuum level. The roughing pump 240 is used to reduce the chamber pressure in the chambers 202, 206 to a level where the turbomolecular pump 230 can take over and achieve target vacuum conditions for performing a plasma etching process.

[0090] Maintaining the correct vacuum levels in the plasma etching operation 102 helps control the density, composition, and uniformity of the plasma, all of which affect the etch rate and pattern fidelity. The roughing pump 240 first evacuates the chambers 202, 206 to a sufficient level before the turbomolecular pump 230 reaches the high vacuum conditions for stable plasma formation. This coordinated operation allows for accurate control of process parameters, such as etch selectivity, profile control, and minimal substrate damage. Thus, the combination of these pumps 230, 240 ensures reliable and repeatable etching results.

[0091] In some embodiments, the turbomolecular pump 230 is further in gaseous communication with the purge pump 250 via the exhaust conduit 242. The purge pump 250 is used to exhaust gas from the interior space 234 of the turbomolecular pump 230 in the pump purge operation 106, thereby removing byproduct particles from the interior space 234 of the turbomolecular pump 230 using the flow of gas. In view of the different roles of the purge pump 250 as compared to the turbomolecular pump 230 and the roughing pump 240, the purge pump 250 can be a different pump than the turbomolecular pump 230 and the roughing pump 240. For example, the purge pump 250 can be a diaphragm pump, a peristaltic pump, a piston pump, or the like.

[0092] In some embodiments, the plasma etching apparatus 200 can further include a valve 244 that regulates whether gas flows to the roughing pump 240 or to the purge pump 250. In some embodiments, the valve 244 is a three-way valve that provides control over the direction of flow of the gas pumped from the turbomolecular pump 230. For example, the three-way valve 244 operates by providing three ports, including an inlet port PI and two outlet ports P2 and P3. The inlet port PI of the three-way valve 244 receives the flow of gas from the turbomolecular pump 230. The first outlet port P2 of the three-way valve 244 directs the flow of gas to the roughing pump 240. The second outlet port P3 of the three-way valve 244 directs the flow of gas to the purge pump 250.

[0093] In some embodiments, the plasma etching apparatus further includes a controller 260 in communication with the plasma power supply 224, the substrate bias RF source 220, the throttle valve 212, the turbomolecular pump 230, the roughing pump 240, the purge pump 250, and the three-way valve 244. For example, the controller can generate a control signal SI to the plasma power supply 224, a control signal S2 to the substrate bias RF source 220, a control signal S3 to the throttle valve 212, a control signal S4 to the turbomolecular pump 230, a control signal S5 to the roughing pump 240, a control signal S6 to the purge pump 250, and a control signal S7 to the three-way valve 244. These control signals SI-S7 are used to manage the operation of the plasma power supply 224, the substrate bias RF source 220, the throttle valve 212, the turbomolecular pump 230, the roughing pump 240, the purge pump 250, and the three-way valve 244, which will be described in more detail below.

[0094] In some embodiments, the controller 260 can include a central processing unit (CPU), a memory unit, and support circuits for controlling the process sequence and regulating the gas flow and plasma processes performed in the plasma etching apparatus 200. The CPU can be any form of general- purpose computer processor that can be used in an industrial setting. Software routines, such as the etching processes described below, can be stored in the memory unit, such as a random access memory, read only memory, floppy, or hard disk drive, or other form of digital storage. The support circuits are coupled to the CPU and can include cache, clock circuits, input / output systems, power supplies, and the like. Bi-directional communication between the controller 260 and the various components of the plasma etching apparatus 200 is handled through a number of signal cables for transmitting control signals S1-S7.

[0095] In an initial step of the plasma etching operation 102, as shown in Figure 2 the rough pump 240 is started, as indicated by the "ON" label in Figure 2 the rough pump 240, to begin evacuating the chambers 202, 206 from atmospheric pressure to a first pressure level (e.g., about 10 -2 torr to 10 -3 torr). During this step, the turbo pump 230 remains deactivated or in an "OFF" state, as indicated by the "OFF" label in Figure 2 the turbo pump 230. Once the rough pump 240 is started, gas is drawn from the chambers 202, 206 and the interior space 234 of the turbo molecular pump 230. In some embodiments, the rough pump 240 is started in response to a control signal S5 from the controller 260, and the turbo molecular pump 230 remains deactivated in response to a control signal S4 from the controller 260.

[0096] In some embodiments, the rough pump 240 is a mechanical pump, such as a lobe or vane pump, that operates by creating a pressure differential that draws gas molecules from the chambers 202, 206 and the interior space 234 of the turbo molecular pump 230. This process begins with a rotor of the rough pump 240 eccentrically mounted within a stator. As the rotor turns, it traps gas molecules in the spaces between the vanes and the stator walls. The rotation of the rotor reduces the volume of these spaces, compresses the gas, and pushes it toward the exhaust port. This continuous cycle of trapping, compressing, and expelling gas molecules effectively reduces the pressure within the chambers 202, 206 and the interior space 234 of the turbo molecular pump 230 from atmospheric pressure to a first pressure level (e.g., about 10 -2 torr to 10 -3torr). The roughing pump 240 is designed to handle relatively high gas loads and is robust enough to manage the initial evacuation from atmospheric pressure. Once the roughing pump 240 has sufficiently reduced the pressure in the chambers 202, 206, it creates an environment suitable for starting the turbomolecular pump 230. The ability of the roughing pump to quickly handle large amounts of gas aids in the initial phase of the plasma etching operation 102, setting the stage for the more precise and high vacuum capabilities of the turbomolecular pump 230.

[0097] In Figure 3 which the roughing pump 240 has reduced the pressure within the chambers 202, 206 and the interior space 234 of the turbomolecular pump 230 from atmospheric pressure to a first pressure level (e.g., about 10 -2 torr to about 10 -3 torr), the turbomolecular pump 230 is started, as indicated by the "ON" label in Figure 3 . This starting evacuates the chambers 202, 206 from the first pressure level to a second pressure level (e.g., about 10 -8 torr to about 10 -9 torr) that is orders of magnitude lower than the first pressure level. In some embodiments, the turbomolecular pump 230 is started in response to a control signal S4 from the controller 260, and the roughing pump 240 can be deactivated in response to the control signal S4 from the controller 260. In some embodiments, the roughing pump 240 is deactivated after the turbomolecular pump 230 is started. In some other embodiments, the roughing pump 240 remains activated after the turbomolecular pump 230 is started.

[0098] In some embodiments, the turbomolecular pump 230 operates by utilizing a series of rapidly rotating rotor blades 232 mounted on a rotor 236, and stationary stator blades 238 that are stationary relative to the rotor blades 232. These blades 232, 238 are used to interact with gas molecules within the turbomolecular pump 230. When the rotor 236 is rotated at high speeds, e.g., over 20,000 revolutions per minute (RPM), the angled blades impart momentum to the gas molecules, effectively directing the gas molecules toward the exhaust duct 242, which is downstream of the turbomolecular pump 230. In some embodiments, the rotor blades 232 are configured in multiple stages, with each stage progressively reducing the pressure. The rotor blades 232 can be made of lightweight, high-strength materials, such as titanium or aluminum alloys, which allow for high-speed rotation without significant wear or deformation. The stator blades 238, which alternate with the rotor blades 238, are fixed and used to redirect the gas molecules toward the rotor 236, thereby increasing the efficiency of the pumping process.

[0099] In Figure 4A which the turbomolecular pump 230 has reduced the pressure within the chambers 202, 206 from the first pressure level (e.g., about 10 -210 -3 The pressure level is lowered to the second pressure level (e.g., approximately 10). -8 10 -9 Following this, plasma power supply 224 is activated by control signal S1 from controller 260, thereby allowing inductor coil 218 to generate and maintain etch plasma 302 in upper chamber 202. Upon activation, plasma power supply 224 supplies radio frequency (RF) energy to inductor coil 218, which is configured as a helical or planar coil surrounding ceramic chamber dome 204. This RF energy induces an oscillating electromagnetic field within upper chamber 202, which in turn ionizes the process gas introduced into upper chamber 202 via gas jet nozzle 210, generating plasma 302 within upper chamber 202. High-energy electrons in the plasma collide with neutral gas molecules, maintaining the ionization process and sustaining a stable plasma environment. The frequency of the RF energy can be in the range of approximately 13.56 MHz, although other frequencies may be used depending on specific process requirements and chamber design.

[0100] In some embodiments, the substrate bias RF source 220 is also activated by a control signal S2 from the controller 260, which enhances control over the ion energy affecting the substrate W. The substrate bias RF source 220 applies a separate RF voltage to the electrostatic chuck cathode 208, generating a bias potential that attracts ions 304 from the plasma 302 toward the substrate W. This bias allows for precise control over ion energy and directionality, thereby enabling anisotropic etching processes where vertical etching rates are faster than horizontal etching rates. The bias RF source can operate at a different frequency than the plasma power supply 224, such as in the range of 300 kHz to 2.5 MHz, to allow for independent control of ion energy and plasma density.

[0101] Figure 4B and Figure 4C This is a magnified cross-sectional view of the substrate W, illustrating the initial and final stages of the plasma etching operation 102. Figure 4BIn some embodiments, an etch target layer 902 is formed over a substrate W, and a patterned mask layer 904 is formed over the etch target layer 902. In some embodiments, the substrate W can be a semiconductor substrate, such as a bulk semiconductor, a semiconductor-on-insulator (SOI) substrate, or the like, which can be doped (e.g., with p-type or n-type dopants) or undoped. The substrate W can be a wafer, such as a silicon wafer. In general, an SOI substrate is a layer of semiconductor material formed over an insulator layer. The insulator layer can be, for example, a buried oxide (BOX) layer, a silicon oxide layer, or the like. The insulator layer is disposed on a substrate, such as a silicon or glass substrate. Other substrates, such as a multilayer or graded substrate, can also be used. In some embodiments, the semiconductor material of the substrate W can include silicon; germanium; compound semiconductors, including silicon carbide, gallium arsenide, gallium phosphide, indium phosphide, indium arsenide, and / or indium antimonide; alloy semiconductors, including silicon germanium, gallium arsenide phosphide, aluminum indium arsenide, aluminum gallium arsenide, gallium indium arsenide, gallium indium phosphide, and / or gallium indium arsenide phosphide; or combinations thereof.

[0102] In some embodiments, the etch target layer 902 can be a metal layer, such as a copper layer, a silver layer, a gold layer, or other metal layer, or combinations thereof. In some embodiments, the etch target layer 902 can be a dielectric layer, such as a silicon oxide layer, a silicon nitride layer, a silicon oxynitride layer, or other dielectric layer, or combinations thereof. In some embodiments, the etch target layer 902 is a polysilicon layer. In some embodiments, the patterned mask layer 904 is a photoresist layer that is coated on the etch target layer 902 using a spin-on coating technique, and then patterned using an acceptable optical lithography technique. The plasma ions 304 etch away portions of the etch target layer 902 that are exposed by the openings of the patterned mask layer 904. As the plasma ions 304 etch away portions of the etch target layer 902, a large amount of byproduct particles 306 (e.g., toxic particles, such as chlorine-containing or fluorine-containing particles) are generated and accumulate on the chamber walls of the upper chamber 202, on the blades 232, 238 of the turbomolecular pump 230, and in the interior space 234 of the turbomolecular pump 230. In some embodiments, the byproduct particles 306 can be non-volatile byproduct particles. Thus, as the etch target layer 902 on this substrate W (or a subsequent substrate) continues to be etched, these byproduct particles 306 can fall off from the chamber walls in the upper chamber 202, or from the blades 232, 238 of the turbomolecular pump 230, thereby contaminating this substrate W or a subsequent substrate.

[0103] Thus, after one or more plasma etching operations 102 are performed on one or more substrates W, a wafer-less auto clean (WAC) operation 104 is performed. As shown in FIG. 1, the WAC operation 104 is performed on the upper chamber 202. The WAC operation 104 is performed to remove the byproduct particles 306 that have accumulated on the chamber walls of the upper chamber 202, on the blades 232, 238 of the turbomolecular pump 230, and in the interior space 234 of the turbomolecular pump 230. In some embodiments, the WAC operation 104 is performed to remove the byproduct particles 306 that have accumulated on the chamber walls of the upper chamber 202, on the blades 232, 238 of the turbomolecular pump 230, and in the interior space 234 of the turbomolecular pump 230, so that the byproduct particles 306 do not contaminate a subsequent substrate W or a subsequent etch target layer 902 formed on a subsequent substrate W. Figure 5As shown, after completing the plasma etching operation 102 on the last substrate W, this substrate W is unloaded from the plasma etching apparatus 200 via the wafer load port 214. In some embodiments, after completing the plasma etching operation 102, the ESC cathode 208 can be lowered by the wafer lift 216 (as shown by arrow A2). After retracting the last substrate W from the plasma etching apparatus 200, a WAC operation is performed by the cleaning plasma 312 to remove byproduct particles 306 from the walls of the upper chamber 202.

[0104] For example, after completing the plasma etching operation on a batch of substrates W, the turbomolecular pump 230, the roughing pump 240, the purge pump 250, the plasma power supply 224, and the substrate bias RF source 220 are deactivated. Next, in response to a control signal SI from the controller 260, the inductively coupled plasma power supply 224 is reactivated without any substrate W being contained in the plasma etching apparatus 200. This activation energizes the inductive coil 218 to generate the cleaning plasma 312 within the upper chamber 202. In some embodiments, the cleaning plasma 312 can be formed from a different gas chemistry than the etching plasma 302 used during the plasma etching operation 102. For example, depending on the nature of the byproduct particles 306 to be removed, the cleaning plasma 312 includes reactive species such as oxygen (O2), fluorine (F2), or chlorine (CI2). These reactive species are chosen because they are capable of chemically reacting with the byproduct particles 306 and volatilizing them, thereby effectively cleaning the chamber surfaces. The cleaning plasma 312 is maintained for a predetermined duration during which the reactive species interact with the byproduct particles 306 to break them down into volatile compounds that can then be pumped out of the upper chamber 202 by the purge pump 250.

[0105] In some embodiments, the WAC operation can be enhanced by applying a bias to the ESC cathode 208, similar to the substrate bias during the etching operation. This bias can help direct the reactive ions towards specific regions of the chambers 202 and 206, thereby improving the efficiency of the cleaning process. Additionally, the wafer lift 216 can be used to adjust the position of the ESC cathode 208, thereby allowing better access to regions that are prone to byproduct buildup.

[0106] While the cleaning plasma 312 can effectively remove the byproduct particles 306 from the walls of the chambers 202 and 206, reaching the inner space 234 of the turbomolecular pump 230 is a challenge. The main reason for this difficulty is the horizontal distance D1 between the inductive coil 218 and the turbomolecular pump 230, or between the lower chamber 206 and the turbomolecular pump 230, which is approximately 40 cm or more. This significant separation limits the ability of the cleaning plasma 312 to penetrate and effectively clean the inner space 234 of the turbomolecular pump 230. Specifically, the cleaning plasma 312 relies on the proximity of the inductive coil 218 to generate and sustain reactive species that can interact with and remove the byproduct particles. However, as the horizontal distance D1 from the inductive coil 218 increases, the density and reactivity of the plasma decrease, reducing its efficiency to reach and clean remote areas, such as the inner space 234 of the turbomolecular pump 230.

[0107] Accordingly, after performing the WAC operation 104, the pump purge operation 106 is performed. Figure 6A FIG. 4A is a side view illustrating the initial step of the pump purge operation 106. Figure 6B FIG. 4B is a three-dimensional view of a pneumatic cleaning device 400, according to some embodiments of the present disclosure, Figure 6C FIG. 4C is a top view of the turbomolecular pump 230. At the initial step of the pump purge operation 106, the pneumatic cleaning device 400 is placed onto the turbomolecular pump 230.

[0108] The pneumatic cleaning device 400 is designed to facilitate the effective removal of the byproduct particles 306 from the inner space 234 and the blades 232, 238 of the turbomolecular pump 230 by using a continuous flow of gas. The flow of gas introduced via the pneumatic cleaning device 400 is exhausted from the turbomolecular pump 230 through the exhaust duct 242, ensuring the effective removal of the unwanted byproduct particles 306.

[0109] As Figure 6BAs shown, in some embodiments, the pneumatic purification device 400 includes a purified gas inlet pipe 402 and a sealing cap 404. The gas inlet pipe 402 is positioned at the center of the top surface of the sealing cap 404. The gas inlet pipe 402 serves as a conduit for introducing a continuous flow of compressed dry air (CDA) or other purified gases (such as nitrogen (N2)) into the turbomolecular pump 230. This airflow helps to loosen and remove byproduct particles 306 that may adhere to the blades 232, 238 or other internal surfaces of the turbomolecular pump 230. The gas inlet pipe 402 is dimensionally adjusted to allow for a precise and controlled flow rate of CDA, thereby ensuring continuous purification of byproduct particles 306 within the turbomolecular pump 230. Positioning the gas inlet pipe 402 at the center of the top surface of the sealing cap 404 helps to distribute the purified gas evenly within the turbomolecular pump 230, thereby enhancing the purification effect. Once introduced into the turbomolecular pump 230, the airflow creates a dynamic environment that drives the byproduct particles 306 toward the exhaust duct 242 connected to the turbomolecular pump 230. This exhaust duct 242 continuously evacuates the air and entrained particles 306, thereby removing the byproduct particles 306 from the turbomolecular pump 230. In some embodiments, the gas inlet pipe 402 includes an inlet nozzle 4022 for connection via a threaded or quick-release connector to an external purified gas source 500 (e.g., a CDA source), and a flexible hose 4024 connecting the inlet nozzle 4022 to a gas inlet opening on the top surface of the sealing cap 404.

[0110] like Figure 6B As shown, in some embodiments, the sealing cap 404 is a disc-shaped plate positioned above the upper opening of the turbomolecular pump 230, surrounding the internal space 234 of the turbomolecular pump 230. The sealing cap 404 has a substantially flat top surface on which the gas inlet pipe 402 and the handle 406 are integrated or mounted. The diameter of the sealing cap 404 is adjusted to match the opening 235 defined by the top rim 231 of the turbomolecular pump 230, thereby ensuring proper alignment during installation.

[0111] The sealing cap 404 mates with a double-sealing O-ring 408 to form an airtight connection with the top rim 231 of the turbomolecular pump 230. In some embodiments, the sealing cap 404 may be made of a material such as stainless steel or aluminum alloy to withstand operational stresses and environmental exposure, thereby ensuring long-term reliability. The sealing cap 404 also provides mechanical support for other components, such as the handle 406 and the bracket 410, thereby allowing the pneumatic purification device 400 to be securely mounted to the turbomolecular pump 230.

[0112] In some embodiments, such as Figure 6BAs shown, the pneumatic purifier 400 further includes two handles 406 attached to or integral with the top surface of the seal cap 404. The handles 406 are spaced apart to facilitate manual manipulation. Each handle 406 is shaped to accommodate the operator's grip, facilitating easy lifting, placement, and removal of the pneumatic purifier 400. In some embodiments, each handle 406 includes a main portion 4062 extending parallel to the top surface of the seal cap 404, and two support portions 4064 extending from opposite ends of the main portion 4062 to the top surface of the seal cap 404. During installation, the operator uses the handles 406 to align the seal cap 404 with the top rim 231 of the turbomolecular pump 230, ensuring safe and accurate assembly.

[0113] The ergonomic configuration of the handles 406 ensures that minimal force is used during assembly and disassembly, reducing the risk of damaging the O-rings 408 or interfering with the sealed connection between the seal cap 404 and the top rim 231 of the turbomolecular pump 230. The handles 406 can be made of the same material as the seal cap 404, or they can comprise a different material from the seal cap 404. For example, the handles 406 can include non-slip grips for better use when operating in a controlled environment, such as a semiconductor manufacturing facility.

[0114] In some embodiments, the sealing mechanism of the pneumatic purifier 400 includes dual-seal O-rings 408 that fit tightly around separate zones on the peripheral wall of the seal cap 404. For example, one O-ring 408 fits tightly around an upper zone on the peripheral wall of the seal cap 404, and another O-ring 408 fits tightly around a lower zone on the peripheral wall of the seal cap 404. The O-rings 408 are used to engage with the top rim 231 of the turbomolecular pump 230, providing an airtight seal. The dual O-ring 408 design is designed to create a redundant seal, ensuring that even if one O-ring 408 is damaged due to surface imperfections or wear, the other O-ring 408 will maintain the integrity of the connection.

[0115] The O-rings 408 comprise materials such as nitrile rubber, which are selected for their chemical resistance, durability, and ability to maintain elasticity under different temperature and pressure conditions. The dual-seal design compensates for potential misalignment or small surface irregularities between the seal cap 404 and the top rim 231 of the turbomolecular pump 230, providing a reliable and consistent seal to prevent the byproduct particles 306 from moving into the chambers 202, 206.

[0116] In some embodiments, the pneumatic purge apparatus 400 further includes brackets 410 extending downwardly from the bottom surface of the sealing cap 404. These brackets 410 are used to land on the perforated cap 233 that is located above the blades 232, 238 of the turbomolecular pump 230. The brackets 410 act as a stabilizing support, ensuring that the sealing cap 404 remains properly positioned and aligned during operation. In some embodiments, the brackets 410 are cylindrical brackets.

[0117] The brackets 410 also provide clearance under the perforated cap 233 for the interior space 234 of the turbomolecular pump 230, ensuring that the gas flow is not obstructed and that the CDA introduced via the gas inlet tube 402 can circulate freely within the interior space 234 of the turbomolecular pump 230.

[0118] In the initial step of the pump purge operation 106, as Figures 6A to 6C depicted, the operator aligns the peripheral wall of the sealing cap 404 with the top rim 231 of the turbomolecular pump 230. The guide and control handle 406 facilitates this alignment. Next, the operator lowers the sealing cap 404 onto the top rim 231 of the turbomolecular pump 230 such that the double-seal O-rings 408 compress against the annular top rim 231 of the turbomolecular pump 230. This compression creates an airtight seal, effectively preventing any byproduct particles 306 from entering the chambers 202 and 206. Once the brackets 410 come into contact with the perforated cap 233 of the turbomolecular pump 230, the operator stops the downward motion of the sealing cap 404. The brackets 410 land on the perforated cap 233, providing additional support and helping to keep the sealing cap 404 firmly positioned over the perforated cap 233.

[0119] In some embodiments, in the initial step of the pump purge operation 106, the turbomolecular pump 230, roughing pump 240, and purge pump 250 are kept deactivated by control signals S4, S5, and S6. The external purge gas source 500 is also kept deactivated by the external controller 510.

[0120] Once the pneumatic purge apparatus 400 is assembled onto the turbomolecular pump 230, as Figure 7In the next step of the pump purge operation 106 shown, compressed dry air (CDA) or another purge gas is introduced via the gas inlet tube 402. The gas flow enters the turbomolecular pump 230 and circulates within the internal space 234 of the turbomolecular pump 230, thereby loosening and blowing away the etch byproduct particles 306 accumulated on the surfaces of the internal space 234 and the vanes 232, 238. The flow of the gas drives these particles 306 towards the exhaust conduit 242 connected to the turbomolecular pump 230, where they are exhausted from the turbomolecular pump 230 along with the gas flow. The continuous purge of the byproduct particles 306 prevents the accumulation of contaminants within the turbomolecular pump 230. This ensures efficient operation of the plasma etching apparatus 200 with minimal downtime for cleaning or maintenance.

[0121] In some embodiments, the purge pump 250 can be activated in response to a control signal S6 from the controller 260 to draw the purge gas flow and the byproduct particles 306 entrained therein from the exhaust conduit 242. In some embodiments, the controller 260 can manage the operation of the three-way valve 244 by sending a control signal S7, such as a control voltage, to switch the open / close positions of the ports in the three-way valve 244 to enable the purge pump 250 to be in gas communication with the exhaust conduit 242. For example, the three-way valve 244 can be switched to have a closed position on the first outlet port P2 and an open position on the second outlet port P3 to allow the purge gas flow and the byproduct particles 306 entrained therein to be drawn by the purge pump 250.

[0122] After the pump purge operation 106 is completed to remove the byproduct particles 306 from the turbomolecular pump 230, the purge pump 250 and the purge gas source 500 are deactivated by the controllers 260, 510, respectively. Next, the operator can use the handle 406 to detach the pneumatic purge apparatus 400 from the turbomolecular pump 230. The modular design of the pneumatic purge apparatus 400 allows for quick assembly on the turbomolecular pump 230 or detachment from the pneumatic purge apparatus 400, thereby minimizing the downtime of the pump purge operation 106.

[0123] Figure 8A FIG. 4 illustrates a perspective view of a pneumatic purge apparatus 400 according to some embodiments of the present disclosure, Figure 8BAn enlarged cross-sectional view of the area where the pneumatic purification device 400 is assembled onto the turbomolecular pump 230 is shown. In some embodiments, the gas inlet pipe 402 has a gas passage 4026 extending through the inlet nozzle 4022, the flexible hose 4024, the top surface of the sealing cap 404, and the bottom surface of the sealing cap 404. The gas passage 4026 terminates at a gas outlet 4028 located in the central area of ​​the bottom surface of the sealing cap 404. This is the location where the purified gas exits the pneumatic purification device 400 after traveling through the gas passage 4026. A bracket 410 extends downward from the bottom surface of the sealing cap 404, and a handle 406 extends upward from the top surface of the sealing cap 404.

[0124] like Figure 8B As shown, when the pneumatic purification device 400 is placed on the turbomolecular pump 230, the sealing cap 404 will be accommodated within the opening 235 defined by the annular top rim 231 of the turbomolecular pump 230. Furthermore, the double-seal O-ring 408 is compressed against the rim-shaped top rim 231, forming an airtight seal with it. In this configuration, the double-seal O-ring 408 may undergo elastic deformation, resulting in an elliptical cross-section with a vertically extending primary axis (i.e., the major axis) and a horizontally extending secondary axis (i.e., the minor axis, which is shorter than the primary axis), caused by the horizontal compressive force applied by the annular top rim 231. The pneumatic purification device 400 can inject purified gas through the gas outlet 4028 at the bottom surface of the sealing cap 404. The injected purified gas can flow into the internal space 234 of the turbomolecular pump 230 through the opening 2332 in the perforated cap 233.

[0125] Figure 9A A bottom view of a pneumatic purification device 400a according to some embodiments of this disclosure is shown. Figure 8B An enlarged cross-sectional view of the area where the pneumatic purification device 400a has been assembled onto the turbomolecular pump 230 is shown. The pneumatic purification device 400a is substantially the same as the pneumatic purification device 400, except that the pneumatic purification device 400a includes a manifold 4042 within a sealing cap 404 for distributing gas within the sealing cap 404. In some embodiments, the manifold 4042 includes an inlet port 4044 at the top surface of the sealing cap 404, which communicates gaseously with a gas passage 4026 in a gas inlet pipe 402, thereby allowing purified gas to enter the manifold 4042 from the gas inlet pipe 402. The manifold 4042 further includes a main passage 4046 having an elongated shape extending in a direction substantially parallel to the top surface of the sealing cap 404, thereby allowing the purified gas to be evenly distributed across the manifold 4042. The manifold 4042 further includes a plurality of outlet ports 4048 located at the bottom surface of the sealing cap 404. These outlet ports 4048 serve as multiple gas outlets, thereby allowing purified gas to be evenly distributed across the area below the sealing cap 404.

[0126] Based on the above discussion, it can be seen that the present disclosure provides advantages in various embodiments. However, it should be understood that other embodiments can provide additional advantages, not all advantages necessarily being recited herein, and no particular advantage is required for all embodiments. One advantage is that etch by-product particles are effectively removed from a turbomolecular pump by using a pneumatic purge device. For example, when only waferless cleaning operations are used to clean a plasma etch device, the failure rate of these cleaning operations is approximately 12% to 16%. This means that about 12% to 16% of the cleaning operations result in a particle count in the plasma etch device exceeding an acceptable threshold. However, when the cleaning process includes both waferless cleaning operations and subsequent pneumatic purge operations, the failure rate can be significantly reduced to less than approximately 6%. Thus, the pneumatic purge operations can significantly improve the cleanliness of the plasma etch device.

[0127] In some embodiments, a method includes reducing a pressure within a chamber from a first pressure level to a second pressure level using a first pump; performing a plasma etch operation in the chamber after reducing the pressure within the chamber to the second pressure level; placing a pneumatic purge device onto the first pump after performing the plasma etch operation; purging an interior space of the first pump by ejecting a purge gas from the pneumatic purge device after placing the pneumatic purge device onto the first pump. In some embodiments, placing the pneumatic purge device onto the first pump includes lowering the pneumatic purge device such that an O-ring of the pneumatic purge device forms a gas-tight seal with a top rim of the first pump. In some embodiments, placing the pneumatic purge device onto the first pump includes moving the pneumatic purge device using two handles on a seal cover of the pneumatic purge device. In some embodiments, placing the pneumatic purge device onto the first pump includes moving a seal cover of the pneumatic purge device into an opening defined by a top rim of the first pump. In some embodiments, placing the pneumatic purge device onto the first pump includes lowering a seal cover of the pneumatic purge device until a bracket extending downward from the seal cover reaches a perforated cover of the first pump. In some embodiments, purging the interior space of the first pump includes activating a gas source in gas communication with a gas inlet tube extending upward from a seal cover of the pneumatic purge device. In some embodiments, the gas source is a compressed dry air (CDA) source. In some embodiments, the gas inlet tube includes an intake nozzle and a flexible hose connecting the intake nozzle to the seal cover. In some embodiments, the first pump is a turbomolecular pump. In some embodiments, the method further includes activating a second pump to draw the purge gas from the interior space of the first pump via an exhaust conduit in gas communication with the interior space of the first pump. In some embodiments, the first pump remains deactivated after activating the second pump.

[0128] In some embodiments, a method includes loading a substrate into a plasma etching device; performing a plasma etching process on the substrate by using a first plasma generated within the plasma etching device, wherein byproduct particles are formed in the plasma etching process; unloading the substrate from the plasma etching device after performing the plasma etching process; cleaning a chamber of the plasma etching device by using a second plasma after unloading the substrate; and blowing the byproduct particles away from blades of a pump of the plasma etching device. In some embodiments, blowing the byproduct particles away from the blades of the pump of the plasma etching device is performed after cleaning the chamber of the plasma etching device by using the second plasma. In some embodiments, the byproduct particles are purged by using a pneumatic purge device. In some embodiments, the method further includes placing the pneumatic purge device onto the pump before blowing the byproduct particles away. In some embodiments, placing the pneumatic purge device onto the pump includes lowering a sealing cap of the pneumatic purge device such that an O-ring around a peripheral wall of the sealing cap is compressed against an annular top rim of the pump.

[0129] In some embodiments, a plasma etching device includes a chamber, an inductive coil above the chamber, a plasma power source electrically connected to the inductive coil, a pump in gaseous communication with the chamber and laterally spaced apart from the inductive coil, and a pneumatic purge device operable to purge the pump. In some embodiments, the pneumatic purge device includes a sealing cap that is received within an opening defined by a top rim of the pump when the pneumatic purge device is placed onto the pump. The sealing cap is shaped to match the opening defined by the top rim of the pump. In some embodiments, the pneumatic purge device further includes a gas inlet tube extending upwardly from a top surface of the sealing cap, and a gas passage extending through the gas inlet tube, the top surface of the sealing cap, and a bottom surface of the sealing cap. In some embodiments, the gas inlet tube includes a flexible hose. In some embodiments, the pneumatic purge device further includes a first O-ring around a peripheral wall of the sealing cap. In some embodiments, the pneumatic purge device further includes a second O-ring around the peripheral wall of the sealing cap. The second O-ring is above the first O-ring.

[0130] In some embodiments, a plasma etching apparatus includes an upper chamber, a plasma power operable to generate a plasma in the upper chamber, a lower chamber connected to a first region of the upper chamber, a wafer chuck in the lower chamber, and a pump connected to a second region of the upper chamber. The plasma power is electrically connected to an inductor coil located on the upper chamber. The pump is separated from the lower chamber by a non-zero horizontal distance. The plasma etching apparatus further includes a pneumatic purge device including a seal cap, a first O-ring, and a gas inlet tube. The seal cap has a gas passage extending through a top surface of the seal cap and a bottom surface of the seal cap. The first O-ring surrounds a peripheral wall of the seal cap and is capable of forming an airtight seal with an annular top rim of the pump. That is, the first O-ring and the annular top rim of the pump can be airtightly joined. The gas inlet tube is above the bottom surface of the seal cap. The gas inlet tube is upstream of the gas passage of the seal cap. In some embodiments, the pneumatic purge device further includes a second O-ring surrounding the peripheral wall of the seal cap. The second O-ring has a height higher than the first O-ring. In some embodiments, the pneumatic purge device further includes two handles at opposite sides of the flexible hose. In some embodiments, the pneumatic purge device further includes a plurality of supports extending from the bottom surface of the seal cap.

[0131] In some embodiments, a plasma etching apparatus includes an upper chamber, a plasma power electrically connected to an inductor coil located on the upper chamber, a lower chamber connected to a first region of the upper chamber, a wafer chuck in the lower chamber, and a pump connected to a second region of the upper chamber. The pump is separated from the lower chamber by a non-zero horizontal distance. The plasma etching apparatus further includes a pneumatic purge device including a seal cap, a gas inlet tube, and two handles. The seal cap has a gas passage extending through a top surface of the seal cap and a bottom surface of the seal cap. The seal cap is shaped to match an opening defined by a top rim of the pump. The gas inlet tube is above the bottom surface of the seal cap. The gas inlet tube is upstream of the gas passage of the seal cap. The two handles are at opposite sides of the gas inlet tube.

[0132] The foregoing outlines features of several embodiments so that a person of ordinary skill in the art can better understand the present disclosure. Those of ordinary skill in the art should appreciate that they can readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and / or achieving the same advantages of the embodiments introduced herein. Those of ordinary skill in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure and that they can make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure.

Claims

1. A plasma etching apparatus, characterized in that, Include: One chamber; An inductor coil is located above the chamber; A plasma power source is electrically connected to the inductor coil; A pump, connected to the gas in the chamber and laterally separated from the inductor coil; and A pneumatic purification device includes a sealing cap whose shape matches an opening defined by a top rim of the pump.

2. The plasma etching apparatus as described in claim 1, characterized in that, The pneumatic purification device further includes: A gas inlet pipe extends upward from a top surface of the sealing cap; and A gas passage extends through the gas inlet pipe, the top surface of the sealing cap, and a bottom surface of the sealing cap.

3. The plasma etching apparatus as described in claim 2, characterized in that, The gas inlet pipe includes a flexible hose.

4. The plasma etching apparatus as described in claim 1, characterized in that, The pneumatic purification device further includes: A first O-ring is placed around the perimeter of the sealing cap.

5. The plasma etching apparatus as described in claim 4, characterized in that, The pneumatic purification device further includes: A second O-ring is located around the peripheral wall of the sealing cap and above the first O-ring.

6. A plasma etching apparatus, characterized in that, Include: Upper chamber; A plasma power source is electrically connected to an inductor coil located on the upper chamber; A lower chamber connects to a first zone of the upper chamber; A wafer chuck is located in the lower chamber; A pump is connected to a second section of the upper chamber, the pump being separated from the lower chamber by a non-zero horizontal distance; and A pneumatic purification device, comprising: A sealing cap having a gas passage extending through a top surface and a bottom surface of the sealing cap; A first O-ring surrounds a circumference of the sealing cover, and the first O-ring is airtightly fitted to an annular top rim of the pump; and A gas inlet pipe is located above the top surface of the sealing cap, upstream of the gas passage of the sealing cap.

7. The plasma etching apparatus as described in claim 6, characterized in that, The pneumatic purification device further includes: A second O-ring surrounds the peripheral wall of the sealing cap, and the height of the second O-ring is higher than that of the first O-ring.

8. The plasma etching apparatus as described in claim 6, characterized in that, The pneumatic purification device further includes: Two handles are located on opposite sides of the gas inlet pipe.

9. The plasma etching apparatus as claimed in claim 6, characterized in that, The pneumatic purification device further includes: Multiple supports extend from the bottom surface of the sealing cap.

10. A plasma etching apparatus, characterized in that, Include: Upper chamber; A plasma power source is electrically connected to an inductor coil located on the upper chamber; A lower chamber connects to a first zone of the upper chamber; A wafer chuck is located in the lower chamber; A pump is connected to a second section of the upper chamber, the pump being separated from the lower chamber by a non-zero horizontal distance; and A pneumatic purification device, comprising: A sealing cap having a gas passage extending through a top surface and a bottom surface of the sealing cap, the shape of the sealing cap being matched to an opening defined by a top rim of the pump; A gas inlet pipe is located above the top surface of the sealing cap, upstream of the gas passage of the sealing cap; and Two handles are located on opposite sides of the gas inlet pipe.

Images