Its advantages are the ease of operation and low cost. While anodic etching is sometimes used 3, the necessity of making electrical contact to slices of small dimensions is invariably a disad vantage. The development of finer semiconductor devices with even thinner layer means that etching systems must process gate materials with high selectivity to extremely thin gate dielectric layer and without etching damage, under precise cd critical dimension control. Plasma cleaning, therefore, is much more than just a cleaning process, it is also a surface. Edc plasma plasma discharge zones paschenslaw erf plasma ehighdensity plasmas edrie microloading silicon grass 172005 eel6935 advanced mems spring 2005 instructor. In order to use this technology for sidewall gate process, an important issue is to achieve a high etching selectivity between sinx and siox. Introduction of plasma cleaning, surface modification, and etching process plasma cleaning is defined as a process that uses an ionized gas to interact with a substrate in order to remove contamination andor modify its surface. A new microwave plasma etching system using time modulation bias technology overview. The pe75 excels at all types of cleaning, bonding, surface modification, and etching. Rack university of tennessee plasma etching outline plasma vs.
Finally, the third element in the oipt ion source is a neutraliser which is basically an electron source. Plasma etching, or reactive ion etching rie, is an important unit operation that is used to remove thin films. According to the model extracted from the experiment, the etch rate was linearly proportional to the gas. High density plasma etching of nickel thin films using a. Several approaches to solve the problem of si3n4sio2si etch selectivity were analyzed.
Etching of the specimens was performed by two methods. Plasma etching is an essential tool in todays world, enabling many of the technologies we take for granted. The plasma source, known as etch species, can be either charged ions or neutral atoms and radicals. It involves a highspeed stream of glow discharge plasma of an appropriate gas mixture being shot in pulses at a sample. Highdensity inductively coupled plasma etching of gaas. Etch rates from 200 to over 3000 nmmin were obtained. Plasma etching is a form of plasma processing designed to remove material from a sample using plasma discharges. Optimization of graphene dry etching conditions via combined. The first day of this course covers plasmaassisted etching phenomena and equipment in a manner that will assist the attendee in understanding and developing plasma etching and rie processes. During the process, the plasma generates volatile etch products at room temperature from the chemical. Plasma etching summary plasma has ions and excited species of reactive gases reactive ions are directed to the surface by electric fields chemical reactions take place at the surface and eat away the material sputtering can also etch away material reaction products are removed in gas form dry etching.
Plasma etching and the benefits over liquid etching. Chamber pressure y pressure torr chemical plasma etching. Plasma etching is a form of plasma processing used to fabricate integrated circuits. A short, selfsufficient introduction to the physics of plasma for beginners as well as researchers in a number of fields. Antonio carlos, 6627, 31270901 belo horizonte, brazil. The emphasis will be on the fundamental physical and chemical processes that determine the consequences of a reactive gas plasmasurface interaction.
A brief discussion of the plasma etching process will clarify the role of the. Using the chemistry of the etch to remove material into a solution liquid or gaseous solution sputtering. Plasma etching is a relatively new technique in the fabrication of integrated circuits. Plasma etching is one of the main applications of plasma treatment and the plasma system known as a plasma etcher is commonly used in production of semiconductor devices. Investigations on an rfplasma related to plasma etching. Plasma is used in applications where it is important to combine materials or to specifically change their surface properties. Tadigadapaplasma etching without ion bombardment, f 2 radicals etch sio 2 veryyy slowly since. Introduction aluminum nitride aln is an iii v group compound semiconductor material with the wide bandgap of 6. Plasma etching is commonly employed in the chemical etching process of wafer fabrication because of its low cost and good control of etching profile and uniformity.
Chapter 2 dry etching characteristics of sin x and sio x icp has been extensively applied to ic manufacturing. The mechanisms of plasma etching of silicon dioxide have been previously. Plasma etching is a synergistic process of both chemical and physical etching, which makes it distinctive from conventional wet etching. Wet chemical etching basics before going into the speci. Plasma etching has become a crucial process step for the microelectronics industry, as computer logic and memory circuits require increasingly precise fabrication of finescale patterns in semiconductors, metals, and insulators. Pdf the novel plasma etching process for defect reduction. Dry etching is an etching process that does not utilize any liquid chemicals or etchants to remove materials from the wafer, generating only volatile byproducts in the process. Berkeley ee143 f2010 lecture 15 1 reactive ion etching r ie plasma wafers rf. Plasma etching demonstration using the pe75 system from. Dry etching substrates are immersed in a reactive gas plasma.
Etching with molten koh was performed as outlined in figure 1. History and future of hitachis plasma etching system. See section 5 for details on people available for contact. Modeling and simulation of plasma etching reactors for. Particle reduction and control in plasma etching equipment. Plasma etching is widely used for etching nanoscale features because it can produce vertical sidewall profiles with little or no undercut.
Optimization of graphene dry etching conditions via combined microscopic and spectroscopic analysis mariana c. Therefore, it can be concluded that the etching of ni films is governed by physical sputtering along with the assistance of chemical reaction. School of electronic engineering, dublin city university, dublin 9, ireland. Introduction to plasma etching willson research group. The most commonly used form of plasma etching is referred to in the microfabrication world as reactive ion etching rie. Etch rate uniformity across wafer key etch variables. B damage and contamination of the etched surface should be minimized plasma etching is a key technology in the fabrication of semiconductor. Dry etching is a type of plasma etching, wherein the materials are blasted with ions in a gaseous atmosphere, as previously described. An introduction to plasma etching for vlsi circuit. Memsii lecture 2 dry etching i university of florida. Introduction of plasma much more than just a cleaning. This anisotropic feature can be further enhanced by allowing the deposition of certain passivating films to occur along vertical sidewalls during the plasma reaction. Dry etching may be accomplished by any of the following.
The potentially damag ing effects of plasma processing on. Emphasis is placed on etching rates, uni formity, anisotropy, selectivity, and critical dimension control. Plasma etching system and its applications to 4532nm. Traditionally, wet anisotropic etching of silicon is used for this purpose 1. The most common plasma etch configurations are reactive ion etch rie, planar etch pe, inductively coupled plasma etch icp etch, or deep reactive ion etch drie etch. However, there are other types of plasma etching, including plasma ashing and ion. Modelling, simulation and multivariable control of plasma. The process dislodges particles of material from the surface and unlike liquid etching acid etching, dry etching is performed either directionally or anisotropically. Introduction etching techniques are commonly used in the fabrication processes of semiconductor devices to remove selected layers for the purposes of pattern transfer, wafer planarization, isolation and cleaning. Its a robust machine that is perfect for any industry needing an affordable plasma etching solution. Suitable for researchers, process engineers, and graduate students, this book introduces the basic physics and chemistry of electrical discharges and relates them to plasma etching mechanisms. Reactive ion etching is an anisotropic processreactive ion etching is an anisotropic process. Plasma etching is a way of creating features in virtually any material, the features can be on the nm scale or 100s of microns.
Aqueous etching of iiiv materials is often an impor tant step in device technology 1, 2. In plasma systems, ions can be accelerated fast enough so as to ram into the surface, knocking out. It is highly controllable and can be used to etch a wide variety of materials. Plasma etching plays an essential role in microelectronic circuit manufacturing. Anisotropic plasma etching has two components, chemical etching neutrals and radicals of the plasma and physical bombardment ion assisted etching reactions vlsi plasma etch processes are characterized by a varying significance of the chemical and physical components. It involves a highspeed stream of glow discharge of an appropriate gas mixture being shot in pulses at a sample.
Reduction of particle contamination in plasmaetching. Introduction to plasma etching university of texas at austin. Many of the plasmas used in dry etching are weakly ionized ionization fraction, x i plasma etching page 3 introduction ideal etching process substrate film to be etched resist substrate resist prior to etch after etch no process is ideal, some anisotropic plasma etches are close ideal etching is the accurate transfer of the pattern to the underlying film. A plasma creates ions, and neutral species that are drawn to a biased electrode. Plasma etchingreactive ion etching and plasma enhanced chemical vapour. Etching can be characterized by how much of the process is. The author looks at the dynamics and stability of magnetoplasma and. Modelling, simulation and multivariable control of plasma etching of silicon and silicon dioxide by liang tan, b. Plasma etching was performed using the system shown in figure 2. Rack university of tennessee terminology etching the process by which material is removed from a surface mask layer used to protect regions of. Chapter 2 dry etching characteristics of sinx and siox. Rie is advantageous over wet etching in that it produces good anisotropy or selectivity where one species is etched much faster than another.
Development and characterization of plasma etching processes for. Inductively coupled plasma etching of gaasalgaas was investigated in bcl3cl2ar using a mixture design experiment. Tailoring gas chemistry for selectivity vs anisotropy. The plasma source, known as etch species, can be either charged or neutral atoms and radicals. Plasma etching techniques including rie, pe, icp, and drie. A novel dry etching of submicron emitter for inpingaas heterojunction bipolar transistor has been developed using inductively coupled plasma etching. The specimen was removed from the epoxy mount, wrapped in platinum wire and immersed in molten koh at 673 k for 10 to 15 sec. Wet anisotropic etching of silicon also provides high reproducibility of. Introduction vertical etching of silicon is widely used for forming relief structures in mems technologies. This futureoriented technology allows for modification of a wide range of surfaces. Plasma etching typically high pressure, no ion bombardment substrate placed on. Plasma etching techniques are typically classed by the configuration of the electrodes.
Publishers pdf, also known as version of record includes final page, issue and volume numbers. Plasma etching, gate shifting, photoresist degradation, roughness, hkmg, 14fdsoi. In the eighties, plasma etching became a mature technique to etch layers and was introduced in the production of integrated. A thesis submitted to dublin city university in fulfilment of the requirements for the degree of doctor of philosophy project supervisors. Thus, many different applications are feasible, for example. Optimization of graphene dry etching conditions via. Pdf the role of plasma etching in the semiconductor technology upon switching from the microscale to the. Introduction of plasma much more than just a cleaning process. The etch rate of metals can be reduced with the introduction of oxygen into the etching chamber, as shown in fig. Advanced plasma etch chambers are equipped with a lot of knobs for controlling the etch process. Apr 20, 2016 its a robust machine that is perfect for any industry needing an affordable plasma etching solution. A new microwave plasma etching system using time modulation. Introduction in largescale integrated circuit lsi manufacturing, particles generated in the process equipment, especially in the plasma etcher, cause serious problems such as decreased yield of lsi in massproduction and low machine operating e.
177 854 603 187 10 18 1384 1486 430 1101 1188 1199 15 772 1469 112 793 158 411 729 200 364 736 539 594 1491 72 1030 1078 1298 407 362 240 1264 1306 72