温馨提示：本站仅提供公开网络链接索引服务，不存储、不篡改任何第三方内容，所有内容版权归原作者所有
AI智能索引来源：http://www.mks.com/n/etch-overview
点击访问原文链接

Etch Overview

进入原网站 导航首页
Etch Overview MKS logo Products MKS Newport Ophir Spectra-Physics Atotech ESI Capacitance Manometers Compact Pressure Transducers General Purpose Pressure Transducers High Performance Pressure Transducers Industrial Pressure Transducers Reference Pressure Transducers View All Capacitance Manometers Mass Flow Controllers & Meters Mass Flow Controllers Mass Flow Meters In Situ Flow Verifiers Flow Ratio Controllers Mass Flow Controller Accessories Vacuum Gauges Vacuum Pressure Transducers Vacuum Pressure Sensors Vacuum Gauge Controllers Vacuum Gauge Accessories Vacuum Gauge Calibration Legacy Vacuum Gauges Gas Analyzers Mass Spectrometers Tunable Filter Spectrometers FTIR Gas Analyzers NDIR Gas Analyzers Vacuum Flanges & Fittings ISO-KF Flanges & Fittings ISO-MF Flanges & Fittings CF Flanges & Fittings Butt Weld Flanges & Fittings Custom Vacuum Fabrication RF & Microwave Generators Microwave Generators RF Power Generators Pressure Controllers & Valves Pressure Controllers Vacuum Isolation Valves Downstream Exhaust Throttle Valves Upstream Flow Control Valves Gate Valves Plasma & Reactive Gas Solutions Remote Plasma Sources Ozone Generators & Systems Dissolved Gas Foreline Plasma Clean Systems Automation, Control & Sensing Heater Jackets & Traps Special Offers Virtual Booth Solutions Semiconductor Electronics and Packaging Specialty Industrial Support Global Service MKS Service Solutions RMA Request Form Health & Safety Forms Contact Global Service Technical Support Product Technical Support Training Programs Contact Product Technical Support Technical Resources Literature Manuals Technical Papers Application Notes Standards Compliance View All Technical Resources Contact MKS Company About MKS Guiding Principles Executives & Fellows Solutions & Innovations Legal Information Environmental, Social and Governance Investor Relations Corporate Governance Stock Information News Releases Events & Presentations Annual Meeting Materials SEC Filings and Forms Financial Analysts All Investor Relations News & Media Trade Shows & Events Press Releases Media Library Careers Job Openings We're Hiring! About MKS MKS Benefits Message from CEO Business Units & Products MY INNOVATION Stories Contact Contact Us Online Corporate Offices Sales & Application Support Calibration, Service & Repairs Product Technical Support Sign In Compare products Product Comparison 

Choose products to compare anywhere you see 'Add to Compare' or 'Compare' options displayed. Compare All Close Shopping cart items Shopping cart items Keyword search Search Submit search mks Search Submit search Products MKS Capacitance Manometers Compact Pressure Transducers General Purpose Pressure Transducers High Performance Pressure Transducers Industrial Pressure Transducers Reference Pressure Transducers View All Capacitance Manometers Mass Flow Controllers & Meters Mass Flow Controllers Mass Flow Meters In Situ Flow Verifiers Flow Ratio Controllers Mass Flow Controller Accessories Vacuum Gauges Vacuum Pressure Transducers Vacuum Pressure Sensors Vacuum Gauge Controllers Vacuum Gauge Accessories Vacuum Gauge Calibration Legacy Vacuum Gauges Gas Analyzers Mass Spectrometers Tunable Filter Spectrometers FTIR Gas Analyzers NDIR Gas Analyzers Vacuum Flanges & Fittings ISO-KF Flanges & Fittings ISO-MF Flanges & Fittings CF Flanges & Fittings Butt Weld Flanges & Fittings Custom Vacuum Fabrication RF & Microwave Generators Microwave Generators RF Power Generators Pressure Controllers & Valves Pressure Controllers Vacuum Isolation Valves Downstream Exhaust Throttle Valves Upstream Flow Control Valves Gate Valves Plasma & Reactive Gas Solutions Remote Plasma Sources Ozone Generators & Systems Dissolved Gas Foreline Plasma Clean Systems Automation, Control & Sensing Heater Jackets & Traps Special Offers Virtual Booth Newport Ophir Spectra-Physics Atotech ESI Solutions Semiconductor Electronics and Packaging Specialty Industrial Support Global Service Technical Support Technical Resources Contact MKS Company About MKS Investor Relations News & Media Careers Contact Contact Us Online Corporate Offices Sales & Application Support Calibration, Service & Repairs Product Technical Support Home Semiconductor Semiconductor Etching Semiconductor Etching Figure 1. Etching to create a pattern on a substrate. In semiconductor device fabrication, etching refers to any technology that will selectively remove material from a thin film on a substrate (with or without prior structures on its surface) and by this removal create a pattern of that material on the substrate. The pattern is defined by a mask that is resistant to the etching process, the creation of which was described in detail in Photolithography. Once the mask is in place, etching of the material that is not protected by the mask can occur, by either wet chemical or by "dry" physical methods. Figure 1 shows a schematic representation of this process.

Historically, wet chemical methods played a significant role in etching for pattern definition, up until the advent of VLSI and ULSI technology. However, as device feature sizes were reduced and surface topographies grew more critical, wet chemical etching gave way to dry etching technologies. This shift was due, primarily, to the isotropic nature of wet etching. Wet etching produces material removal in all directions, as shown in Figure 2, which results in a discrepancy between the feature size defined by the mask and that which is replicated on the substrate. VLSI and ULSI designs demand much more precise mask to pattern feature size correlation than was needed at larger feature sizes. In addition, aspect ratios (depth to width ratios) in advanced devices increased and achieving these ratios required an ability to anisotropically etch material using directional etching technologies. Figure 3 provides a schematic to help in understanding isotropic vs. anisotropic feature generation and directional etching. The final blow to wet etching's utility in advanced processing may have been the fact that many of the newer materials being used for device fabrication did not have accessible wet chemistries that could be employed for etching. These issues combined to relegate wet etch technologies to nearly exclusive use for cleaning rather than in etching applications. Only devices that have relatively large feature sizes (such as some MEMS structures) continue to employ wet methods for etching. Surface cleaning has been discussed in detail in Wafer Surface Cleaning.

Figure 2. The isotropic character of wet etch processes. Figure 3. The isotropic character of wet etch processes. Anisotropic etching uses a suite of technologies cumulatively known as "dry" etch. These technologies are universally used for etching in VLSI and ULSI device fabrication and they will be the only methods discussed in detail in this Section. Dry etching can remove material through physical means such as ion impact accompanied by ejection of material from the substrate or by chemical reactions that convert substrate material to volatile reaction products that can be pumped away. Dry etching technologies include the following commonly used methods (whether the etch process occurs through chemical etching, physical etching, or a combination as noted in parenthesis):

Isotropic Radial Etching (Chemical) Reactive Ion Etching (Chemical/Physical) Sputter Etching (Physical) Ion Milling (Physical) Ion Beam Assisted Etching (Physical) Reactive Ion Beam Etching (Chemical/Physical) All dry etching technologies are conducted under vacuum conditions with the pressure dictating, to some extent, the nature of the etch phenomenon.

Table 1 is taken from Wolf and Tauber and shows the relative pressure regime and generalized characteristics for the different etch methods. While there are a number of specific variants on the equipment and process characteristics used for etching, we will limit our discussion to a brief description of the process basics and the three primary etching methodologies identified in Table 1.

Physical Sputtering and Ion Beam Milling Physical momentum transfer Directional etch possible Poor selectivity Radiation damage possible Higher Excitation Energy Reactive Ion Etch ~ 100 mTorr Physical (ion) and chemical Directional More selective than sputtering Isotropic Radial Etching Higher Pressure Chemical (faster by 10 Ð 10,000x) Isotropic More selective More selective Lower Excitation Energy

Table 1. Pressure regimes and characteristics for different etch methods.

Basic Processes In-depth discussions of plasma etching fundamentals are available in a number of texts (Wolf and Tauber, Sze) and the interested reader is referred to these sources. Here we provide only the briefest description of the basic fundamentals of plasma generation. Within a plasma etching process, a number of physical phenomena are at work. When a strong electrical field is created in a plasma chamber using either electrodes (in the case of a DC potential or RF excitation) or a waveguide (in the case of microwaves), the field accelerates any available free electrons raising their internal energy (there are always a few free electrons in any environment resulting from cosmic rays, etc.). Free electrons collide with atoms or molecules in the gas phase and, if the electron transfers enough energy to the atom/molecule in the collision, an ionization event will occur producing a positive ion and another free electron. Collisions that transfer insufficient energy for ionization can nevertheless transfer sufficient energy to create a stable but reactive neutral species (i.e., molecular radicals). When sufficient energy is fed to the system, a stable, gas-phase plasma containing free electrons, positive ions and reactive neutrals is produced.

In plasma etching processes, the atomic and molecular ions and/or reactive neutrals from a plasma can be used to remove material from the substrate by either physical or chemical pathways, or by mechanisms that employ both. Purely physical etching (Figure 4) is accomplished by using strong electric fields to accelerate positive atomic ions (usually an ion of a heavy inert element such as argon) towards the substrate. This acceleration imparts energy to the ions and when they impact the substrate surface, their internal energy is transferred to the atoms in the substrate. If sufficient energy is transferred, a substrate atom will be ejected into the gas phase to be pumped away by the vacuum system. The incident ion is neutralized in the collision and, since it is a gas, it desorbs into the gas phase to be re-ionized or pumped out of the system.

Figure 4. Physical etching of a substrate. Chemical etching differs from physical etching in that it employs a chemical reaction between reactive neutral species created within the plasma and the substrate material. The most common type of chemical etching involves halide chemistries in which chlorine or fluorine atoms are the active agent in the etching process. A representative chemistry for etch processes is the use of NF3 for silicon etching. The chemical reaction sequence in this etch process is:

NF3 + e- → •NF2 + F• + e-

Si(s) +4F• → SiF4↑

NF3 is dissociated in the plasma to produce highly reactive atomic fluorine radicals. These radicals react with silicon in the substrate to produce silicon tetrafluoride, SiF4, which is a volatile gas that can be pumped away. In this manner silicon is etched from the substrate. Chemical etching, like wet etching, is an isotropic process without directionality (Figure 5). The reason for this is that the sticking coefficient of reactive neutrals is relatively low, so most impacts with the substrate surface do not result in etching, but rather with simple desorption of the reactive neutral back into the gas phase. This phenomenon results in an evening-out of the etch process within the feature being etched and ultimately isotropic character in the etch.

Figure 5. The source of isotropic character in plasma etching. Most of the etching technologies used in modern device fabrication incorporate aspects of both physical and chemical etching. In processes such as reactive ion etching (RIE), directional etching is achieved by biasing the substrate so that ionic species from the plasma are accelerated towards the substrate surface. There they interact with the surface and the reactive neutrals to produce volatile products that can be pumped away (Figure 6). The ion energy in RIE is much lower than that employed for physical etching technologies and ion bombardment effects are negligible. The transfer of ion energies to the surface can enhance the directionality through improved adsorption of reactant species on the bombarded surface (incoming ions create high energy defects where adsorption and reaction preferentially occur) and through enhanced by-product desorption (incoming ion energies are transferred to reaction products causing them to desorb from the surface).

Figure 6. Chemical etch enhanced by low energy ion bombardment. Semiconductor Etching Products Deposition Direct Vacuum and Pressure Measurement Pressure Control Flow Control and Measurement Remote RF Plasma Generation RF Power Generation Microwave Generation Mass Spectroscopy Ozone Generation and Delivery Process Automation Vacuum Piping Solutions Related Topics Semiconductor Etching

Isotropic Radical Etching Reactive Ion Etching Physical Sputtering and Ion Milling Front-end Semiconductor

Silicon Wafer Production Wafer Surface Cleaning Lithography Thin Film Deposition Chemical Mechanical Planarization Thermal Oxidation Dopant Atom Diffusion Ion Implantation Inspection For additional insights into semiconductor topics like this, download our free MKS Instruments Handbook: Semiconductor Devices & Process Technology

Request a Handbook

©2026 MKS Inc. All rights reserved.

Terms of UsePrivacy Mon.-Fri. 8:30-17:00 CST Contact Us Careers Legal About Us Investors Facebook YouTube LinkedIn Sign In

Email Address  Required Password:  Required Need a new account? Register Password Reset Enter your email address below to reset your account password. Email Address:  Required Cancel Password Reset
Email Verification Required


Sign In Cart Items Updated

Close Remove Product Remove this product from your comparison list?
Cancel Check Order Status Provide an order number and postal code to check the status of an order or download an invoice for an order that has shipped. Login to view your complete order history.
Order Number: Required Delivery ZIP/Postal Code:  Required

Sign In Required



To access this and other valuable technical resources, please sign in or register for a new online account. Cancel Add to Cart Part:   Availability:  Add to Cart Also available on Newport.com Qty:  Availability:  Shop at Newport.com  Ultra-High Velocity Learn More Invalid VAT ID

VAT ID has invalid format. It will not be saved with the order when submitted.
Cancel   added to your cart Part:   Availability:  View Cart & Checkout Continue Shopping   added to quote Model:   Request Quote Continue Shopping
Close

智能索引记录