Good qualitative agreement was obtained between the model predictions and meas ured etch rates as a function of pressure, power, and flow rate. For plasma etching of silicon nitride, usually gases containing fluorine like cf4, nf3, chf3 and sf6 18 are used, in most cases in mixtures with other gases as o2, n2, h2, ar and no. Ideally, the gas mixture will react readily with the material being etched, while reacting minimally with materials that should not be etched, thus achieving high selectivity. Inductively coupled plasma reactive ion etching icprie of sic single crystals using sf6based gas mixtures was investigated. A plasma generates reactive species which are not available in a bottle plasmas consist of electrons, neutralsradicals, and ions generated through collisional processes ions are accelerated through the boundary layer sheath at near normal incidence directional reactant exposure with simultaneous ion bombardment enhances etch.
Turn the rf level knob on the chamber to the \hi setting and make sure there is a light purplepink color in the chamber indicating a plasma. Etching is the process of selectively removing mask patterned materials from the wafers surface to create desired patterns on the wafers surface. To view 3d images in this pdf, please open file in adobe. Modeling and simulation of plasma etching reactors for. The emphasis will be on the fundamental physical and chemical processes that determine the consequences of a reactive gas plasmasurface interaction. It is a highly controllable process that can process a wide variety of materials, including semiconductors, dielectrics and some metals.
Uniformity of etching in parallel plate plasma reactors. Energy and vacuum is needed to maintain plasma gas discharge. Plasma etching plasma etching is used to roughen a surface, on the microscopic scale. The reactive ion etching of transparent electrodes for flat panel displays using arci2 plasmas j. 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. The company has grown to become a leading manufacturer of plasma cleaning and etching systems. A new microwave plasma etching system using time modulation bias technology overview. The choice of the plasma chemistry, that is the gas mixture used, is made according to the volatility and stability of the etch product. A new microwave plasma etching system using time modulation. Plasmaassisted wafer bonding has realized hybrid siiiiv structures, using the iiiv material as an efficient gain medium while maintaining the economic and electronic integration benefit of a silicon platform sun et al. Applications include dry etching of dielectric materials.
A new microwave plasma etching system using time modulation bias technology 346 mpu microprocessing unit and gate oxide equivalent thickness is 23 nm. H thin films for display devices using sf 6 o 2 and nf 3 o 2 were investigated using a dualfrequency capacitively coupled plasma reactive ion etching ccprie system. The oxygen plasma etching polymer was chosen as a model experimental system. Plasma etching of undoped silicon in chlorine plasmas fits neatly into this mechanistic niche discussed below, since at ordinary temperature chlorine atoms and molecular chlorine barely attack undoped silicon at all when there is no ion bombardment. For microelectronics applications, the plasma process affects the film quality as well as device characteristics. Advances in materials science and engineering hindawi. Plasma etching is a relatively new technique in the fabrication of integrated circuits. During the process, the plasma generates volatile etch products at room temperature from the chemical.
Pdf inductively coupled plasma reactive ion etching of titanium. In the plasmaetching mode, the electrons accelerated by the applied rf. It involves a highspeed stream of glow discharge of an appropriate gas mixture being shot in pulses at a sample. What links here related changes upload file special pages permanent. 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. Reactive ion etching systems rie etch process plasma.
Plasma etching is a form of plasma processing used to fabricate integrated circuits. Saia general electric company corporate research and development schenectady, new york introduction general principles a. Silicon surface reacts with xef 2, and forms byproduct molecule of sif 4. The surface of the component is etched with a reactive process gas.
The reactive ion etching of transparent electrodes for. On the other hand the use of oxygen 0v bias plasmas can be used for isotropic surface termination of ch terminated diamond surface. Berkeley ee143 f2010 lecture 15 1 reactive ion etching r ie plasma wafers rf. Otherwise, increase the pressure slightly with the oxygen controls and try to initiate the plasma again. Memsii lecture 2 dry etching i university of florida. Fesem micrographs of etched ni thin films at various cl2 concentrations. Quasineutral means that overall the net charge of the plasma is. Simultaneously, if a plasma is observed, start a stopwatch. One major advantage to rie over other forms of etching is that the process can be designed to be highly anisotropic, allowing for much finer. A plasma creates ions, and neutral species that are drawn to a biased electrode. Plasma etching techniques are typically classed by the configuration of the electrodes.
It was introduced in the seventies, mainly for stripping resists. Rie is a type of dry etching which has different characteristics than wet etching. Xef 2 etch system for mems release plasma etching, pecvd. To cover the range of applications, one etch is tuned for deep reactive ion etching of high aspect ratio microstructures in silicon, while another is tuned for high aspect ratio nanoscale structures. Several approaches to solve the problem of si3n4sio2si etch selectivity were analyzed. Weve developed a wide range of solutions for plasma cleaning, plasma etching, reactive ion etching rie, plasma treatment, surface modification, and other facets of plasma processing. At relatively high pressures, 100 mtorr, rapid etching with a small degree of. Rie uses chemically reactive plasma to remove material deposited on wafers. Plasma cleaning and etchers plasma clean plasma etch, inc. Material from the surface is etched away, converted to the gas phase and removed by the vacuum system. Reactive ion etching systems rie plasma etching samco inc. High density plasma etching of nickel thin films using a. Plasma etch is the use of a radio frequency rf excited plasma to produce chemically reactive species from various gases. Modeling and simulation of plasma etching reactors for microelectronics demetre j.
Etching, deposition, and wafer bonding techniques for semiconductor applications 83 and iedf include the bias voltage vb, the ion density, the gas composition, and the mean free path which also depends on the aforementioned parameters. Deep nld plasma etching of fused silica and borosilicate glass mohammed j. Mechanisms of silicon etching in fluorine and chlorine. This results in a low etch rate and nonvertically etched walls. The subject matter is therefore well tuned to the needs of workers in the semiconductor industry, although it would also serve as an excellent textbook for a final undergraduate year or postgraduate course on the processing of semiconductor materials. Reactive ion etching rie is a plasma etching technology to fabricate micro and nanostructures. Surface reaction modeling for plasma etching of sio 2 thin film ye o n h o i m nanomaterials research ce nter and school of chemical engineering and technology, chonbuk national university, 66414, 1ga, duckjindong, duckjingu, chonju 561756, korea received 5 september 2006, accepted 26. The reactive plasma is exposed to the wafer surface and etches away theread more. Investigation of plasma etching mechanisms using beams of. Plasma etching is considerably advantageous in comparison to wet etching. Plasma etching and the benefits over liquid etching. Introduction to plasma etching university of texas at austin.
High density plasma etching of nickel thin films using a cl2ar plasma 941 figure 2. The plasma is generated under low pressure by an electromagnetic field. Mechanisms for plasma and reactive ion etchfront roughening. Comparative study with al2o3 article pdf available in applied surface science 366 january 2016 with 5,062 reads how we measure reads. The volatile compounds are removed from the sample surfaces, and isotropic or anisotropic. During plasma etching, the highly energetic and reactive species produced from a selected process gas, such as o 2 or a fluorine bearing.
Reactiveion etching rie is an etching technology used in microfabrication. Index termscryogenic etching, profile control, reactive ion. Reactive ion etching rie is a high resolution mechanism for etching materials using reactive gas discharges. In the present work, an extension of the previous model. Basically, all chemical etch ing processes probably consist of three sequential steps 57, 58. The first day of this course covers plasma assisted etching phenomena and equipment in a manner that will assist the attendee in understanding and developing plasma etching and rie processes. Table 1 presents a list of various halogen, hydride, and methylcompounds, as well as their respective volatility for the most common elements and materials that plasma etching deals with presently. Reactive ion etching rie is an etching technology used in microfabrication. During rie etching processes, volatile compounds are formed in interaction of sample surfaces and highenergy ionsradicals generated by lowpressure plasma. Tailoring gas chemistry for selectivity vs anisotropy. The plasma source, known as etch species, can be either charged or neutral atoms and radicals.
Reactive ion etching is an anisotropic processreactive ion etching is an anisotropic process. Ruzicb center for plasma material interactions, university of illinois at urbanachampaign, urbana, illinois. Plasma etching is a wellmastered technique for patterning features larger than 0. Economou plasma processing laboratory, department of chemical engineering, university of houston, houston, tx 772044792, usa abstract as microelectronic devices continue to shrink and process requirements become ever more stringent, plasma modeling and simulation. Xef 2 vaporphase etching is a powerful etching technique for microelectronics fabrication. A study on the reactive ion etching of sic single crystals using. Ability to etch fine features and highly anisotropic etch profiles are among the most important benefits of plasma etching. Plasma is the fourth state of matter, formed by ionizing gas particles, through radio frequency or heating. 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. Avoid use of energetic reactive ions to achieve atomic. The reactive gases cbrf 3 and cf 4 have both been found to be effective in the reactive ion etching of niobium. Deep nld plasma etching of fused silica and borosilicate glass. 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.
Surface reaction modeling for plasma etching of sio thin film. Plasma etchingdeposition a 6inch parallel plate rf. Reactive gas ion beams have been used to investigate mechanisms of plasma and reactive ion etching processes. The emphasis will be on the fundamental physical and chemical processes that determine the consequences of a reactive gas plasma surface interaction. The type and ratio of gases used in a plasma etch is chosen depending on the material being etched, the masking material, and the etch stop material. Tin removal from extreme ultraviolet collector optics by inductively coupled plasma reactive ion etching h. Reactive ion etching or ion enhanced plasma etching is a standard technology for pattern.
Pdf characterization of random reactive ion etchedtextured. Polymerization of fluorocarbons in reactive ion etching. Guidelines for etching silicon mems structures using fluorine high. Reactive ion etching systems rie etch process plasma etch. 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. Investigations on an rfplasma related to plasma etching. Shkel microsystems laboratory, university of california, irvine, ca, usa, 92697 email. Inductively coupled reactive ion etching system torr.
The technique allows independent control of ion energy, flux and angle of incidence and background pressure. Tin removal from extreme ultraviolet collector optics by. Wang, in coatings for biomedical applications, 2012. Oxygen plasma etching can be used for anisotropic deep etching of diamond nanostructures by application of high bias in inductively coupled plasma reactive ion etching icprie reactor.
Reactive ion etching and plasma desmear equipment, including the patented magna system which requires no cf4 gas for etch back. High density plasma etching of nickel thin films using a cl. Technology development of 3d silicon plasma etching. A plasma is a quasineutral gas of charged and neutral particles. Ee143 f2010 lecture 14 6 3 etching selectivity s wet etching s is controlled by.
In order to understand the process of plasma etching, it is important to understand the working of a plasma. Etching of protonexchanged lithium niobate can prevent the lif deposition to a large extent because of the greatly reduced lithium concentration in lithium niobate. Highenergy ions from the plasma attack the wafer surface and react with it. Ee143 f2010 lecture 14 etching university of california. Berkeley ee143 f2010 lecture 15 3 remote plasma reactors plasma sources 1 transformer. The challenge today and in the future is to develop efficient processes in the direction of the nanotechnologies, thus, decreasing the critical dimension towards the nanometer scale, as well as in the direction of the micro. The investigation was carried out by varying the rf power ratio.
In summary, a general model on plasma thin film processes used in the tft fabrication, which includes both deposition and. Pdf an inductively coupled plasma reactive ion etching of tin thin films was carried out using a cl2ar gas chemistry. Only used for sputtering system not for etchingonly used for sputtering system not for etching. Chemistry in the glow discharge process parameter effects a. This nonplasma etching process shows unlimited etch selectivity of silicon against other materials such as. Plasma etching, as the name implies, is a technique of etching in which plasma is used as an etchant instead of strong acids. The surface of the component is usually etched with a reactive process gas which gives both a chemical and physical effect on the surface. In addition, the reaction byproducts should be highly volatile. Deposition and etching mechanisms in plasma thin film. Introduction to plasma etching willson research group.
The third etch described is tuned for creating structures in silicon dioxide. Plasma etching techniques including rie, pe, icp, and drie. Plasma etching is a synergistic process of both chemical and physical etching, which makes it distinctive from conventional wet etching. 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. Advanced plasma etch chambers are equipped with a lot of knobs for controlling the etch process. In summary, a general model on plasma thin film processes used in the tft fabrication, which includes both deposition and etching mechanisms, is presented.
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