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Glossary: S

Here you are going to find explications of important terms in plasma technology:

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P,Q

X,Y,Z

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sample holder: Receiver for the treatment of samples. In general, it is adjusted to the work piece so that the latter is positioned accurately and mechanically secured.
Scanning Electron Microscope (SEM): see “electron microscope (EM)”
scratch resistant: In order to protect sensitive (polycarbonate) or heavily strained materials, a scratch-resistant layer can be applied onto a surface. Such layers can be evaporated, or deposited via vapour deposition, sputtering, dipping, plasma treatment, or spin coating. The layers can consist e.g. of tungsten carbide, diamondlike carbon layers, silicon oxide, boron or titan compounds. For CVD and plasma processes, certain precursors are needed, molecules that are composed of the elements that are to be deposited on the surface. If such a precursor (e.g. HMDSO) is brought into a plasma, then it is fragmented and blown onto the surface. Since it is not necessary to fragment the precursor by high temperatures, the surface is not strained as much.
scratch resistant layers: see „scratch resistant“
scratch resistance: see „scratch resistant“
sealing: With the increasing number of electronic and electromechanic parts, their sealing against extraneous environmental influences becomes more and more important. Here, mostly polyurethane, silicone, or epoxy pottants are in use. Good adhesion of these pottants on the various materials of cases, conductor boards, and components is important.
silicon wafer: Basis for modern semiconductor technology. The wafer with a diameter of up to 300mm is cut off from a silicon single crystal.
silicone: A chain shaped polysiloxane, mostly poly(dimethylsiloxane) having found widespread application as non-resinating oil and grease. Networkable silicones are e.g. used in sealings. Silicones feature a very low surface energy (about 20 mN/m), therefore wetting well most other surfaces, while not being wetted by most other liquids. Hence, even traces of silicones disturb most coating processes. The cleaning of surfaces containing silicones is feasible by special plasma methods.
silicone cleaner: see „removing silicone“
silicone free: see „removing silicone“
silicones: Silicones are higher molecule compounds that are based on a three-dimensional frame, composed of alternating silicon and oxygen atoms. Silicone, in one of its simplest and most widespread applications, serves in the building sector as sealer for the filling of splices. Because of its multifunctional properties (high heat resistance, temperature acclimation, longevity, adhesive or isolating features, plasticity…) the application is nearly unlimited and represented in most multifaceted industrial application techniques. Amongst others, it is as well used in the production of car varnishes, furniture polishes, and motor oils.
SIMS: Secondary Ion Mass Spectrometry, sensitive method for thin layer analysis. The surface is bombarded with high energy primary ions, which leads to the emission of, beside other particles, secondary ions from the layer material. These can directly be detected by means of mass spectrometry.
size: Lubricant for the production of yarns. Sometimes it has an interfering influence on further treatment steps, e.g. coating. Through a plasma treatment two effects can be attained: first, the vaporisation of the size and thus a cleaning effect, or second improved networking through the energy supply, which also facilitates the further treatment.
sliding friction: see "friction"
splicing Teflon: see „etching Teflon“
sputter etcher: Installation that makes use of dry etching based on the sputtering effect (physical etching, dusting off and emission of atoms from the solid body’s surface induced through ion bombardment, respectively) in order to ablate the edge layer and impurity layers, respectively.
sputtering: Designation for plasma cleaning involving the bombardment of high energy ions from a plasma onto a surface, thereby ablating surface atoms. In pure sputter processes, Argon is often employed as process gas. Plasma cleaning by sputtering is also called “micro-sandblasting”. Furthermore, sputtering is applied in thin film technology as a method for the generation of vapour phases with definite composition by bombardment of a sample of the desired material (the so-called target).
sputtering system: See „PVD“; sputtering is a technical variant of PVD coating.
static friction: see "friction"
sterilisation: see „aseptic cleaning“
sticking improvement: see „agglutination“
stiction: see "friction"
strengthening adhesion: see „agglutination“
sulphur hexafluoride: Under normal conditions, sulphur hexafluoride (SF6) is an absolutely inert gas; in the plasma process, however, it generates highly reactive fluoride atoms and sulphur fluoride radicals, and represents thus one of the most aggressive plasma process gases (see also “tetrafluormethane”).
surface activation: Processing, like e.g. the agglutination, flocking, varnishing, coating of plastics, often causes problems. Plastics have mostly non-polar surfaces. That’s why adhesives and varnishes are often incapable to generate sufficient adhesion to these surfaces. An example is metal oxides on surfaces that can be removed by a plasma. Through certain pre-treatment methods (e.g. plasma), polar groups are built up on the surface that improve adhesion without affecting the plastic material.
surface cleaning: see „precision cleaning“
surface coating: see „surface treatment”
surface energy: see „surface tension“
surface energy: Surface energy is a material parameter that defines how much a surface is wettable by a liquid. The surface energy can be distinguished via measurement of the contact angles of droplets of different kinds of liquids on the surface. The surface energy of many plastics can be increased significantly through a plasma treatment, which leads to an enhanced adhesion in agglutination and varnish processes.
surface engineering: Surface engineering means the sum of all technologies to change the properties of surfaces. By means of the surface engineering techniques, the surface can then be optimized at certain job specifications and thus achieve several functions, as e.g. mechanical protection (wear, friction), barrier functions (corrosion resistance, permeation, inward diffusion, thermal insulation), interface interaction (biocompatibility, wettability, varnishability), electric functions (conductivity, electrical insulation), or optical functions (reflexion, absorption, decoration).
surface modification: see „functionalisation“
surface refinement: A refinement of plastic parts is achieved via applying a chromium layer.
surface tension: In every material, the molecules attract each other more or less, even without being chemically bound (see “cohesion”). In gases, these inner adhesion forces are too weak to hold matter together, in solid bodies they are so strong that the single molecules can no longer move freely.
In a liquid, the molecules interact mainly via van der Waals forces (state of aggregation). On the inside, the adhesional forces act symmetrically on the particles. In the edge layer, these molecules are not attracted equally from all sides any more, generating a resulting force towards the inside; that’s the reason why energy has to be fed in order to bring a particle from the inside into the edge layer.
Therefore, all materials tend to minimise their surface. The surface tension / surface energy can be examined very nicely through test inks. This is done by observing the test ink when applying different inks of differing surface tensions onto the material. Another example for the effect of the surface tension is a needle that can be laid upon a water skin. If the surface tension is decreased, e.g. by a washing-up liquid, the needle is going to sink to the ground. The surface tension of solid bodies can be increased through cleaning, integration of foreign atoms, and generation of polar groups. This can be done by radicals, activated and ionised particles in plasmas.
surface treatment: Processing, like e.g. the agglutination, flocking, varnishing, coating of plastics, often causes problems. Plastics have mostly non-polar surfaces. That’s why adhesives and varnishes are often incapable to generate sufficient adhesion to these surfaces. Through certain pre-treatment methods, polar groups are built up on the surface that improve adhesion without affecting the plastic material. Else, an increase in adhesion can be achieved through cleaning the surface.
This precision cleaning can be achieved e.g. by fogging (sputtering) of the contamination, thus through accelerated particles impinging on the surface. Furthermore, the organic impurities like oil and grease can be removed from the sample via cold combustion by radicals and activated atoms which are available in a plasma. Precision-cleaning by plasma cleanses surface gently, without environmentally harmful detergents and solvents. Another possibility to give a surface defined and designed mechanical, optical, chemical, and physical properties is to provide them with a coating.
This can be done by superimposing molecules (silanes, SiOx) onto the surface, e.g. through vaporisation, deposition from a gas phase or through application of some special precursor-gas (TEOS, HMDSO) via plasma. These coating layers can have e.g. scratch resistant, barrier, hydrophobic, or hydrophilic properties.