Us3943047a selective removal of material by sputter. Plasma etching involves physical bombardment of the substrate by an ion which is nominally inert. Sputter deposition and etching of metallization seed layer. Scribd is the worlds largest social reading and publishing site. This passivation may, in fact, affect the resistance of the upper and lowerlevel metal contacts if it is not removed by sputter etching or other means. Plasma sputter coating in conventional sem sputter coating a gold goldpalladium, or platinum target is bombarded with heavy gas atoms usually argon but air is a fair substitute. The etching rate is determined by the sputtering yield. Study of plasma and ion beam sputtering processes 1 the conversion of neutral particles into ions, electrons plasma. A method is provided for forming seed layers in semiconductor device channels or vias by using an inert gas sputter etching technique. Sputter etching is chosen in cases where a high degree of etching anisotropy is needed and selectivity is not a concern.
Etching when considering the chemical or physical nature of various plasmas, it can be deduced that plasma can be used to etch, clean or modify a surface. The requirements for highfidelity, anisotropic etching are discussed. Enrol and complete the course for a free statement of participation or digital badge if available. Ion beam sputter deposition and etching system, electron. Dry etching we covered wet etching which is essentially chemical and isotropic because it is chemical, it is highly selective now we consider dry etching which has largely replaced wet based on highly anisotropic sputtering process and may include reactive ions, so can also be chemical and selective. Dry etch processes, ion beam etching, plasma etching, reactive ion etching. This involves ejecting material from a target that is a source onto a substrate such as a silicon wafer. Sputteretching was applied to type 303, 304, 430 and 420 stainless steels to form conical or ringshaped protrusions on the surface, and the tensile test of the substrate with protrusions, the. This book provides the most practical way to carry out many of the process steps involved in integrated circuitry. Etching different etching processes are selected depending upon the particular material to be removed. Ion etching was performed by rf resputtering of gzo thin films at constant rf power of 250 w on substrates located horizontally and the time of sputter etching was changed. Sputtering effects can arise in two contexts within a dryetch process. Incoming ions cause removal of volatile products that.
However, it is a physical process very like this that we need if we are to achieve a vertical etch profile. Sputter deposition and etching of metallization seed layer for overhang and sidewall improvement. Greene 2 1 ghent university, department of solid state sciences, krijgslaan 281 s1, 9000 ghent, belgium 2 materials science and physics departments and the frederick seitz materials research laboratory, university of illinois, urbana, illinois 61801, usa sputter deposition is a widely used technique to deposit thin films on substrates. The etching chamber is separated from the ion source and the surface of the specimens is not revealed to the plasma generated in the ion source. Examples of results obtained with this system are given and demonstrated with sem photographs. Us3943047a selective removal of material by sputter etching. A variety of sample holders and ion source configurations allow for a diverse range of applications to be carried out. Etching is a critically important process module, and every wafer undergoes many etching steps before it is complete. The plasma produces energetic free radicals, neutrally charged, that react at. In the semiconductor industry sputtering is used to etch the target. After etching the top plate and stripping the remaining photoresist, the.
Sputtering deposition usually uses an argon plasma because argon, a noble gas, will not react with the target material. For many etch steps, part of the wafer is protected from the etchant by a masking material which resists etching. The etching rate is governed by surface kinetics in this regime. In chemical dry etching, free radicals are produced in a plasma and react at the surface of the substrate. Handbook of plasma processing technology 1st edition fundamental, etching, deposition and surface interactions.
Purchase handbook of sputter deposition technology 2nd edition. A conductive coating is needed to prevent charging of a specimen with an electron beam in conventional sem mode high vacuum, high voltage. In general, there are two classes of etching processes. Except for slight sputtering effects, al presents no problems with respect to selectivity, since it is passivated in fluorinebased plasmas by the formation of aluminum fluo ride. Nanomasters ion beam milling and etching systems are field proven, fully automated systems that provide ease of use, high reproducibility, and reliable performance with extremely good uniformity. Pdf formation of fine protrusions by sputter etching of. Good step coverage, t rt pecvd plasma enhanced surface diffusion without need for. Physical etching or sputter etching purely physical etching highly directional. Dry etching and sputtering request pdf researchgate. Dry etch processes dryetching semiconductor technology from a. Reactive species in plasma found to accelerate dry etching.
An etching ion source is optional for nanomatching samples prior to sputter deposition. Once the condition for a sustained discharge is met, the tube exhibits the characteristic glow discharge, so called because of the associated luminous glow. In standard plasma systems, the plasma density is closely coupled to the ion. Not surprisingly, the surface finish is rather poor and there are issues with particles contaminating the devices. Ion sputter etching caused change of surface morphology of gzo films analyzed by dektak 150 profilometer and afm park xe 100. Selective plasma etching of polymeric substrates for advanced applications. The process of plasmadry etching is quite simple straightforward and can be consid ered as the. A method of ion beam sputter etching a surface of a substrate as claimed in claim 1 wherein the low energy carbon atoms have energies less than about 2 ev. There is also provided a field free region adjoining the surface of the wafer which is being etched.
Resputtering is reemission of the deposited material during the deposition process by ion or atom bombardment. Handbook of metal etchants paglione research group. Plasma rie etching birck nanotechnology center fundamentals and applicationsfundamentals and applications 1. Make sure this fits by entering your model number patent search on cd containing over 50 related patents in high resolution pdf format cd of information on system and method for performing sputter etching using independent ion and.
Some practical applications of plasma include clearing surface films and sputtering materials into a surface. Also, since temperatures are lower and melting is not an. Now, since the surface has more of b, more of it will sputter off. Etching is used in microfabrication to chemically remove layers from the surface of a wafer. Manual vapor etching of oxide is particularly useful in cases where fragile. Sputter coating in scanning electron microscopy is a sputter deposition process to cover a specimen with a thin layer of conducting material, typically a metal, such as a goldpalladium aupd alloy. Us6228754b1 method for forming semiconductor seed layers by. Lower pressures are used to attain even more directional etching 10100 mtorr. During the removal of material selectively, by the sputter etching of the surface of a semiconductor wafer, the wafer is moved so as to produce a continuously varying angle of incidence between the ion beam and the wafer surface. Typically there are about 1015 cm3 neutral species 1 to 10% of which may be free radicals and 1081012 cm3 ions and electrons. Handbook of plasma processing technology 1st edition.
Ion beam current is displayed digitally for quick evaluation of the operating conditions. Ion beam sputter etching of orthopedic implant alloy mp35sfa nkesulting effects on fatigue properties edwin g. 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. Sputtering effects can arise in two contexts within a dry etch process. The functionality is a result of gas or gases used, the process pressure vacuum, form of energy rf, dc, microwave, low frequency, etc. In all types of ion sources, the gas ions are produced by various types of gas discharge including electron collisions with gas atoms. Wintucky and mark christopher lewis research center cleveland, ohio and eugene bahnuik and simon wang case western reserve university cleveland, ohio prepared for the fifteenth international electric propulsion conference. In order to form a functional mems structure on a substrate, it is necessary to etch the thin films previously deposited andor the substrate itself. Incoming ions cause removal of volatile products that arise from the interaction between the dryetch plasma and the surface to be etched. Plating is done with multiple parts or hangers, and there is free etching, where parts are dropped. One commercial process for cutting inkjet printer nozzles uses sandblasting. This overview of the technology describes the advantages provided by plasmas, plasma fundamentals, and a range of plasma processes relevant to the deposition and etching of thin films for microelectronics and other fields.
New patent cd for system and method for performing sputter. Reactive ion etching is an anisotropic processreactive ion etching is an anisotropic process. Ion beam sputtering an overview sciencedirect topics. If the sputter yield of one species a is larger than the other b, then the surface will initially be depleted of a. Plasmathe rm reactive ion etching system model 70 serie. Dry etching substrates are immersed in a reactive gas plasma. Greene 2 1 ghent university, department of solid state sciences, krijgslaan 281 s1, 9000 ghent, belgium 2 materials science and physics departments and the frederick seitz materials. A method of ion beam sputter etching a surface of a substrate as claimed in claim 2 wherein the argon ions have a high energy between about 300 ev and about 2000 ev. Hf vapor etching and cleaning of silicon wafer surfaces.
Ion beam milling and etching systems nanomaster, inc. However, sputtering yield variations are smaller compared to vapor pressure variations. Silicon etching in fluorine and chlorinecontaining plasmas 1711 as pressure is decreased below about loomtorr, the potential across the discharge characteristically increases, and with this there is a corresponding rise in sheath potentials. If the mean free path of the ions is high, the particles impact on the wafer surface. Handbook of sputter deposition technology 2nd edition fundamentals and applications for functional thin films, nanomaterials and mems. Lecture 36 high selectivity low selectivity etch, part 3. Dry etching is an important process for micro and nanofabrication.
Increasing the power increases both there are three principal mechanisms. Dry etching based silicon micromachining tu ilmenau. The technique etches back the seed layers which results in a reduction of seed layer overhang at the top of the channels or vias, thereby enhancing the subsequent filling of the channel or vias by conductive materials. Selective plasma etching of polymeric substrates for.
The general requirements are a source of electrons, a small region. At very low pressure, the ion energy is high, reactant. Sputter deposition is a physical vapor deposition pvd method of thin film deposition by sputtering. An equilibrium will be reached around the stochiometric ratio. Us6228754b1 method for forming semiconductor seed layers.
Sputter etching was applied to type 303, 304, 430 and 420 stainless steels to form conical or ringshaped protrusions on the surface, and the tensile test of the substrate with protrusions, the. As a consequence, the sputtering beam strikes the wafer surface. Glow discharge tbsputter sputter coating technical brief 6 issue 1 3 glow discharge. Therefore the initial layers of film will be more closely related to the target composition. Etching tanks used to perform piranha, hydrofluoric acid or rca clean on 4inch wafer batches at laas technological facility in toulouse, france. Ar sputter etch to improve the insulator quality in metal. Handbook of sputter deposition technology 2nd edition. Metal atoms ejected from the target by the ionized gas cross the plasma to deposit onto the any surface within the coating unit including the specimen. Fabrication and application of selfmasked silicon nanostructures.
The most useful system for the sputter etching is the ion beam sputtering system. Parallel plate systems reactive ion etching rie mode for more directed etching, need stronger ion bombardment. Mechanisms of silicon etching in fluorine and chlorine. Etching improves image contrast on highly polished cross section sem samples and can expose interesting aspects of various types of biological samples. Wet etching where the material is dissolved when immersed in a chemical solution. Dry etching mechanisms the mechanism of dry etching is very similar to the wet etching mechanism. Etching is used in microfabrication to chemically remove layers from the surface of a wafer during manufacturing.
Sputter etching low anisotropy plasma etching or wetetching plasma etching steps 1. Selective plasma etching of polymeric substrates for advanced. A brief discussion on the various dry etch techniques available is followed by a description of a batch reactive sputter etch system that fulfills all patterning requirements. Such systems can be manual or automatic cycling, with wafers. Oct 18, 2001 b chemical cleaning is performed prior to sputter cleaning, whereas document d1 does not mention any cleaning step before the sputter etching.
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