Dictionary

  • Abrasion: Refers to the wearing away of a material’s surface due to frictional forces.
  • Absorption: Describes the process of matter penetrating in bulk into other matter, such as a gas dissolving in a liquid.
  • Accelerator: A compounding material used in small amounts with a vulcanizing agent to speed up vulcanization.
  • Accelerator, delayed action: An accelerator that, when used with other curing agents, initially shows little cross-linking at vulcanizing temperatures, followed by rapid cross-link abreviations formation.
  • Accuracy: The concept of exactness; in a test method, it denotes the absence of bias, and in a measured value, it denotes the absence of both bias and random error.
  • Activator: A compounding material used in small proportions to enhance the effectiveness of an accelerator.
  • Adhesion failure: Refers to the loss of structural integrity caused by the separation of two bonded surfaces about at the bond interface.
  • Adsorption: The retention of matter on a surface by another material.
  • Agglomerate, latex: A cluster of rubber particles in a colloidal aqueous suspension of such particles.
  • Agglomerates: Clusters of particles of compounding materials contained in a continuous rubber phase.
  • Aging (act of): The exposure of materials to a deteriorating environment for a specified time interval.
  • Aging: The irreversible change of material properties during exposure to a deteriorating environment for a specified time interval.
  • Aliphatic: Refers to straight-chain hydrocarbons, including three sub-groups: alkanes, alkenes, and alkynes.
  • Alloy: A unique composition of two or more polymers, with one or more polymers treated or processed in a special way to confer enhanced performance characteristics on the resulting material.
  • Alpha particle: A positively charged particle consisting of two protons and two neutrons.
  • Amorphous: Refers to materials with no definite arrangement of atoms.
  • Ampere or Amp: A unit of current, representing the rate at which electrons move past a reference point.
  • Angstrom (Ã): A unit of length equal to one ten-thousandth of a micron (10-4 µm) or 100,000,000 Ã = 1 cm.
  • Anisotropic: Describes an etch process that exhibits little or no undercutting.
  • Anneal: A high-temperature processing step designed to minimize stress in the crystal structure of the wafer.
  • Anticoagulant: A substance added to field latex to retard bacterial action, preventing rapid coagulation of the latex.
  • Antidegradant: A compounding material used to retard deterioration caused by oxidation, ozone, light, and combinations of these factors.
  • Anti-extrusion ring: A thin ring installed on the low-pressure side of a seal to prevent elastomer extrusion into the clearance gap.
  • Antiflexcracking agent: A compounding material used to retard cracking caused by cyclic deformations.
  • Antioxidant: A compounding material used to retard deterioration caused by oxidation.
  • Antiozonant: A compounding material used to retard deterioration caused by ozone.
  • Antistatic agent: A material that reduces the tendency for accumulation of electric charge on the surface of an article.
  • Aromatic oil: A hydrocarbon process oil containing at least 35% aromatic hydrocarbons by mass.
  • Ash: The residue left after incineration of a material under specified conditions.
  • Ashing: The process of removing photoresist with oxygen plasma.
  • Atmospheric-pressure chemical vapor deposition (APCVD): A method for depositing layers at atmospheric pressure.
  • Attenuation: The reduction in intensity of energy traveling through a medium or space.
  • Autoclave: A vessel used for vulcanizing rubber compounds using steam pressure.
  • Backrinding is a molding defect characterized by the shrinkage of rubber adjacent to the flash line below the surface of the molded product. This often leads to a ragged and torn flash line.
  • Bake-out is a secondary post-curing operation aimed at removing residual volatile materials.
  • Batch refers to the product resulting from a single mixing operation.
  • Beta particle is an electron or positron emitted from a nucleus.
  • Bipolar transistor is a transistor composed of an emitter, base, and collector, whose action depends on the injection of minority carriers from the base by the collector.
  • Blank is a portion of a rubber compound with a suitable volume to fill the cavity of a mold.
  • Bleeding is the exuding of a liquid compounding material from the surface of vulcanized or unvulcanized rubber.
  • Blister is a cavity or sack that deforms the surface of a material.
  • Bloom refers to a liquid or solid material that has migrated to the surface of rubber, altering its surface appearance.
  • Blowing agent is a compounding material used to produce gas through chemical or physical action (or both) during the manufacturing of hollow or cellular articles.
  • Borophosphosilicate glass (BPSG) is a compound containing boron, phosphorus, silicon, and oxygen.
  • Bound monomer is a monomer that combines or reacts with itself or other types of monomers in a polymerization reaction to form a polymer.
  • Breakaway friction is the force required to overcome friction and initiate the motion of a body over a surface.
  • Brittle point is the temperature at which elastomers break when subjected to an impact.
  • Bulk modulus of elasticity, also known as the compression modulus, represents the ratio of compressive force applied to a surface per unit surface area to the change in volume of the substance per unit volume.
  • Bumping in the molding process involves the application, release, and reapplication of pressure before vulcanization begins. This helps to vent entrapped gases, ensuring complete filling of the mold.
  • Butt joint is a connection made by joining two ends cut at right angles.
  • Calender: Machine with parallel, counter-rotating rolls for sheeting, laminating, and coating rubber to controlled thickness/surface condition.
  • Capacitor: Device storing electrical charge on conductors separated by dielectric.
  • Cell: Single small cavity partially/fully surrounded by walls.
  • Chalking: Powdery residue on rubber surface from degradation.
  • Chamber clean: Gas/plasma cleaning to prevent buildup on chamber walls.
  • Chemical vapor deposition (CVD): Method for depositing layers on wafers using chemical reactions.
  • Chemisorption: Chemical adsorption with weak bonds between gas/liquid molecules and solid surface.
  • Chip: Individual integrated circuit/discrete device on a wafer.
  • Coagent: Compounding ingredient to enhance cross-linking efficiency.
  • Coefficient of friction: Force required to move surfaces divided by force normal to them.
  • Coefficient of thermal expansion: Change in volume per unit volume for a temperature rise at constant pressure.
  • Cohesive failure: Rupture within a single layer of an assembly.
  • Cold flow: Slow deformation at/below room temperature under gravity.
  • Comonomer: Monomer species forming a copolymer.
  • CMOS (Complementary metal oxide semiconductor): N- and P-channel MOS transistors on the same chip.
  • Composite seal: Seal composed of dissimilar materials.
  • Compound: Intimate admixture of polymer(s) with necessary materials for finished article.
  • Compression: Deformation on a seal, calculated by dividing deformation by original cross-sectional diameter.
  • Compression molding: Material placed in mold cavity and compressed for shaping.
  • Compression set: Residual deformation after removal of compressive stress.
  • Conditioning (environmental): Storage of rubber under specified conditions prior to testing.
  • Conditioning (mechanical): Prescribed deformation of specimen prior to testing.
  • Conductive rubber: Elastomer with high conductivity.
  • Conductor: Material easily conducting electricity.
  • Copolymer: Polymer formed from two different monomers.
  • Covalent bonding: Chemical bonding with shared electron pairs.
  • Crack(s), atmospheric: Fissures from natural weathering on rubber surface.
  • Crack(s), ozone: Fissures from exposure to ozone-containing environment.
  • Crack(s), flex: Fissures from cyclic deformation (bending) on rubber surface.
  • Creep: Time-dependent strain resulting from stress.
  • Cross-link: Chemical bond bridging polymer chains.
  • Cross-linking agent: Compounding material producing cross-linking in rubber.
  • Crystallization, polymer: Arrangement of disordered polymer segments into geometric symmetry.
  • Cure: See vulcanization, the preferred term.
  • Decibel (dB): Expression of the ratio of two power or voltage values in logarithmic terms.
  • Density: Mass-per-unit volume of a material.
  • Deposition: Process where layers form through a chemical reaction, coating the wafer surface.
  • Desiccant: Compounding material used to absorb moisture in rubber mix, minimizing porosity risk during vulcanization.
  • Developer: Chemical to remove areas defined in wafer fabrication masking and exposure step.
  • Die swell: Difference between extrudate dimensions and corresponding die orifice dimensions.
  • Dielectric: Material conducting no current when voltage is across it.
  • Diene polymer: Polymer formed from one or more monomer species, at least one being a diolefin.
  • Diffusion: Spontaneous mixing of substances in contact or separated by a permeable barrier.
  • Diffusion (in semiconductor fabrication): Introduction of minute impurities (dopants) into a substrate, dependent on temperature and time.
  • Dipole: Molecule with positive and negative charge centers.
  • Dispersing agent (latex): Surface-active substance to suspend solid compounding materials in a liquid medium and stabilize the dispersion.
  • Dispersion (act of): Applying shearing forces to uniformly distribute compounding materials in a continuum material.
  • Dopant: Element altering semiconductor conductivity by contributing a hole or electron to the conduction process.
  • Doping: Introduction of impurity atoms (dopants) into the crystal lattice of a semiconductor.
  • Dry etching: Selective material removal using gas or plasma.
  • Dry-ox: Growth of silicon dioxide using oxygen and hydrogen to form water vapor at process temperatures.
  • Dumbbell specimen: Flat specimen with a narrow, uniform cross-sectional central portion.
  • Durometer: Instrument measuring the indentation hardness of rubber.
  • Dynamic random access memory (DRAM): Memory device storing digital information in a volatile state.
  • Dynamic seal: Seal preventing leakage between surfaces moving relative to each other.
  • Elastic limit: Greatest stress a material can sustain without any permanent strain remaining upon complete release of the stress.
  • Elastomer: Viscoelastic macromolecular material capable of responding to large deformations.
  • Electronegativity: Material’s tendency to attract electrons to itself.
  • Elongation: Extension of a uniform specimen section expressed as a percentage of the original length.
  • Elongation, ultimate: Elongation at the time of rupture.
  • Emulsifying agent (latex): Surface-active substance used to disperse immiscible liquid compounding material in another liquid and stabilize the emulsion.
  • Epitaxial: Growth of a single-crystal semiconductor film upon a single-crystal substrate.
  • Erasable programmable read-only memory (EPROM): Device allowing stored information to be erased using ultraviolet light.
  • Esters: Compound formed by eliminating water and bonding an alcohol and an organic acid.
  • Etch: Process for removing material in a specified area through a wet or dry chemical reaction or by physical removal.
  • Ethers: Compound characterized by “O” bonding.
  • Evaporation: Process using heat to change a material from its solid state to a gaseous state, depositing it on wafers.
  • Exposure: Method of defining patterns by interacting light or energy with photoresist sensitive to the energy source.
  • Extender: Organic material used to augment the polymer in a compound.
  • Extensometer: Device for determining elongation of a specimen as it is strained.
  • Extrudate: Material issuing from an extruder.
  • Extruder: Machine forcing rubber or rubber mix through an orifice, often shaped to the geometry of the desired product.
  • Extrusion: 1) Continuous shaping of a material during plastic passage through a die. 2) Displacement of a part of the seal into the clearance gap under fluid pressure or thermal expansion.
  • Face seal, flange seal: An axial contact seal.
  • Fatigue life (dynamic): Number of deformations required to produce a specified state of fatigue breakdown in a test piece or product under prescribed conditions.
  • Field oxide: Region on an electrical device where the oxide functions as a dielectric.
  • Field-effect transistor (FET): Transistor consisting of a source, gate, and drain, controlled by the transverse electric field under the gate.
  • Filler: Solid compounding material, usually in finely divided form, added to a polymer for technical or economic reasons.
  • Fissure: Surface split or crack.
  • Flash: Excess material protruding from the surface of a molded article at the mold junctions.
  • Flex life: Number of cycles required to produce a specified state of failure in a flexed specimen.
  • Flow: Process step where elevated wafer temperature smoothes out the topography of deposited PSG or BPSG surface layer due to low viscosity at elevated temperatures.
  • Flow marks: Marks or lines on a molded product caused by imperfect fusion or “knitting” of material.
  • Fluorocarbon elastomer: Also known as fluoroelastomer.
  • Fluorosilicone: A fluorinated silicone elastomer.
  • Foam stabilizer (latex): Substance used in the preparation of latex foam to stabilize it before gelation, drying, and vulcanization.
  • Formula: List of materials and their amounts used in the preparation of a compound.
  • Frequency: Number of periodic oscillations, vibrations, or waves per unit of time.
  • Furnace: Equipment used to maintain a region of constant temperature with a controlled atmosphere for processing semiconductor devices.
  • Furnace carbon black: Type of carbon black produced by the decomposition reaction of hydrocarbons in a high-velocity stream of combustion gases under controlled conditions.
  • Gallium arsenide (GaAs): Semiconductor material with advantages of producing radiation-resistant and higher-speed devices than those produced using silicon as a substrate.
  • Gamma radiation: Emission of high-energy photons.
  • Gasket: Deformable material clamped between stationary faces to prevent the passage of matter through an opening or joint.
  • Gate oxide: Thin, high-quality silicon dioxide film inducing charge and creating a channel between source and drain regions of an MOS transistor.
  • Gel, dry rubber: Portion of unvulcanized rubber insoluble in a chosen solvent.
  • Gland: Cavity into which a seal is installed.
  • Grain anisotropy: Introduced into rubber during processing operations.
  • Gum compound: Rubber compound containing only necessary ingredients for vulcanization and small amounts of other ingredients for processing, coloring, and improving resistance to aging.
  • Hardness: Material’s ability to resist a distorting force (indentor point).
  • Heat buildup: Accumulation of thermal energy generated within a material due to hysteresis, resulting in an increase in temperature.
  • Hertz (Hz): International unit for frequency, representing the number of cycles per second.
  • Hole: Absence of a valence electron in a semiconductor crystal, equivalent to motion of a positive charge.
  • Homogeneous: Having uniform composition or structure.
  • Homogenization: Repeated passage of raw rubber through a mill or mixing device to ensure uniformity.
  • Homopolymer: Polymer formed from a single monomer species.
  • Hybrid integrated circuit: Structure consisting of one or more semiconductor devices and a thin-film integrated circuit on a single substrate, usually ceramic.
  • Hydrogen bonding: Unusually strong dipole-dipole attractions occurring among molecules where hydrogen is bonded to a highly electronegative atom.
  • Hydrophilic: Affinity toward water (water-loving); a hydrophilic surface allows water to spread across it in large puddles.
  • Hydrophobic: Aversion to water; a hydrophobic surface forms droplets and does not allow large puddles of water. These surfaces are often termed “de-wetted.”
  • Hygroscopic: Attracts and absorbs water.
  • Hysteresis: The lagging of strain behind stress during deformation.
  • Impact resistance: Resistance to fracture under shock force.
  • Impedance: Total opposition offered by an electric circuit to the flow of an alternating current, comprising resistance and reactance.
  • In situ: Refers to sequential process steps completed without removing the wafers from one process environment to another.
  • Inhibitor: Material used to suppress a chemical reaction.
  • Integrated circuit (IC): Circuit with many elements fabricated and interconnected on a single chip of semiconductor material.
  • Interlayer dielectric (ILD): Films insulating between the wafer surface and the first metal layer, typically doped silicon dioxide formed from a silicon source gas, oxidizing gas, and dopant source gases.
  • Intermetal dielectric (IMD): Films insulating between two layers of conductive metal.
  • Ion: Atom that has gained or lost electrons, becoming a charged particle.
  • Ion implantation: Introduction of selected impurities (dopants) through high-voltage ion bombardment to achieve desired electronic properties in defined areas.
  • Ionic bonding: Electrostatic attraction between oppositely charged ions, characterized by electron transfer.
  • Isotactic: Polymeric molecular structure containing a sequence of regularly spaced asymmetric atoms arranged in like configuration in the polymer chain.
  • Isotropic: Having the same properties in all directions.
  • Ketone: An organic compound containing the carbonyl group -C=O.
  • Kinetic friction: The minimum force required to maintain a body in motion over a surface.
  • Latex: Colloidal aqueous dispersion of rubber.
  • Light-emitting diode (LED): Semiconductor device converting the energy of minority carriers combining with holes into light.
  • Lip seal: Custom seal, static or dynamic, that seals on a flexible extension.
  • Lithography: Process of pattern transfer; when light is used, it is termed photolithography, and when patterns are measured in microns, it is referred to as microlithography.
  • Lot: Mass of material or collection of articles of similar composition and characteristics.
  • Low-pressure chemical vapor deposition (LPCVD): System with the deposition environment less than atmospheric pressure, often using a quartz boat placed in a furnace brought up to deposition temperature.
  • Mask: Glass plate covered with an array of patterns used in the photomasking process. Mask patterns may be formed in emulsion, chrome, iron oxide, silicon, or other opaque materials.
  • Masterbatch: Homogeneous mixture of rubber and one or more materials in known proportions for use as a raw material in the preparation of the final compounds.
  • Mastication: Breakdown or softening of raw rubber or a mix by the combined action of mechanical work (shear) and atmospheric oxygen, sometimes accelerated by the use of a peptizer and frequently at elevated temperatures.
  • Metalization: 1) Deposition of a thin film pattern of conductive material onto a substrate to provide interconnection of electronic components or conductive contacts. 2) The layer of high-conductivity metal used to interconnect devices on a chip, commonly aluminum is used.
  • Microhardness: Hardness measured with an instrument having a smaller indentor and applying a lower force than the standard instrument, allowing measurements on smaller specimens or thinner sheets not amenable to measurement by normal instruments.
  • Micron (µm): A unit of length, one millionth of a meter.
  • Mill: Machine used for rubber mastication, mixing, or sheeting, having two counter-rotating rolls with adjustable longitudinal axis separation that usually rotate at different speeds.
  • Mismatch: Defect resulting from differing cross-section dimensions in adjacent mold halves.
  • Mixer: Machine that incorporates and disperses compounding ingredients into rubber to form a mix or a compound through the action of mechanical work (shear).
  • Mixer, internal: Machine with a closed cavity where a specially shaped rotor (or rotors) masticates the rubber or incorporates and disperses compounding materials into the rubber, or both.
  • Modulus, tensile: See tensile stress, at given elongation, the preferred term.
  • Modulus, Young’s: Ratio of normal stress to corresponding strain for tensile or compressive stresses below the proportional limit of the material.
  • Mold cavity: Hollow space in the mold designed to impart the desired form to the product being made.
  • Mold marks: Surface imperfection transferred to a molded product from corresponding marks on a mold.
  • Mold release: See release agent (mold).
  • Molding shrinkage: Difference in dimensions between a molded product and the mold cavity in which it was molded, measured when both the mold and product are at normal room temperature.
  • Molding, compression: Process of forming a material to a desired shape by flow induced by a force applied after the material is placed in the mold cavity.
  • Molding, injection: Process of forming a material by forcing it from an external heated chamber through a sprue (runner, gate) into the cavity of a closed mold using a pressure gradient independent of the mold clamping force.
  • Molding, transfer: Process of forming a material by forcing it from an auxiliary heated chamber through a sprue (runner, gate) into the cavity of a closed mold using a pressure gradient dependent on the mold clamping force.
  • Molecule: Smallest quantity of a substance retaining the properties of that substance.
  • Monomer: Low-molecular-weight substance consisting of molecules capable of reacting with like or unlike molecules to form a polymer.
  • Mooney viscosity: Measurement of the plasticity of compounded or uncompounded elastomeric seal material.
  • Necking: Localized reduction in cross-section that may occur in a material under tensile stress.
  • Negative resist: Photoresist that remains in areas not protected from exposure by the opaque regions of a mask but is removed by the developer in protected regions. A negative image of the mask remains following the development process.
  • Network: Three-dimensional structure formed by interchain or intrachain bonding of polymer molecules in combination with chain entanglements.
  • Nip: Radial clearance between rolls of a mill or calender on a line of centers.
  • Nitrile (Buna-N): A common hydrocarbon elastomer.
  • Non-fill: Defect resulting from the failure of the rubber to fill out all the mold pattern detail.
  • Non-polar: Pertaining to an element or compound that has no permanent dipole moment.
  • Occlusion: Process by which materials are entrapped within the folds of a given substance during manufacture.
  • Off-register: Misalignment of mold halves causing out-of-round O-ring cross-section.
  • Olefins: A family of hydrocarbons with one carbon-carbon double bond.
  • Oligomer: A polymer consisting of only a few monomer units, such as a dimer, trimer, tetramer, etc., or their mixtures.
  • O-ring: See seal, O-ring.
  • Outgassing: The release of adsorbed or occluded gases or water vapor, usually by heating.
  • Oxidation: A chemical reaction in which a compound loses electrons.
  • Oxidation: The growth of oxide on silicon when exposed to oxygen. This process is highly temperature-dependent.
  • Paraffins: Saturated straight-chain hydrocarbons of the methane series.
  • Passivation: The final layer in a semiconductor device, forming a hermetic seal over the circuit elements. Plasma nitride and silicon dioxide are materials primarily used for passivation.
  • Pellicle: A thin film of an optical-grade polymer that is stretched on a frame and secured to a mask or reticle. This solves the problem of airborne contamination forming on the mask. The pellicle keeps the dirt out of the focal plane.
  • Perfluoroelastomer: A fully fluorinated fluoroelastomer.
  • Permanent set: The permanent distortion of an elastomer after being strained.
  • Permeability: The permeation rate divided by the pressure gradient of the gas or vapor. For a homogeneous material that obeys Fick’s law, the permeability is equal to the product of the diffusion coefficient and the solubility coefficient of the gas or vapor.
  • Permeance: The permeation rate divided by the pressure differential of a gas or vapor between opposite faces of a solid body.
  • Permeation rate: The flow rate of a gas or vapor, under specified conditions, through a prescribed area of a solid body, divided by that area.
  • Physiosorption: A physical adsorption process in which there are van der Waals forces of interaction between gas or liquid molecules and a solid surface.
  • Phosphosilicate glass (PSG): A material commonly used for dielectrics before metalization, also for passivation. These films are composed of phosphorous-doped silicon dioxide.
  • Photoresist: The light-sensitive organic polymer film spun onto wafers and exposed using high-intensity light through a mask. The exposed photoresist is dissolved with developers, leaving a pattern of photoresist which allows etching to take place in some areas while preventing it in others.
  • Physical vapor deposition (PVD): The layering of a vapor, usually by means of evaporation or sputtering.
  • Pigment: An insoluble compounding material used to impart color.
  • Plasma: High-energy gas made up of ionized particles.
  • Plasma etching (PE): The use of energized gases to chemically remove a surface.
  • Plasma nitride: A silicon-nitrogen film deposited using PECVD, most often as a final passivation layer.
  • Plasma-enhanced chemical vapor deposition (PECVD): A deposition system primarily used for deposition of silicon oxide and silicon nitride films. A plasma is used in addition to a heat source which allows for lower temperature processing (200°â€”400°C).
  • Plasticizer: A compounding material used to enhance the deformability of a polymeric compound.
  • Polar: Describing a molecule or radical that has, or is capable of developing, electrical charges. Polar molecules ionize in solution and impart conductivity.
  • Polymer: A substance consisting of macromolecules characterized by the repetition (neglecting ends, branch junctions and other minor irregularities) of one or more types of monomeric units.
  • Polymer network: A three-dimensional reticulate structure formed by chemical or physical linking of polymer chains.
  • Polysilicon (Poly): Polycrystalline silicon, extensively used as conductor or gate material in a highly doped state.
  • Porosity: The presence of numerous small cavities.
  • Post-cure: Heat or radiation treatment, or both, to which a cured or partially cured thermosetting plastic or rubber composition is subjected to enhance the level of one or more properties.
  • Pot life: The period of time during which a reacting thermosetting plastic or rubber composition remains suitable for its intended use after mixing with a reaction-initiating agent.
  • Precision: A concept of uniformity based on the magnitude of the random errors. The smaller the random errors, the higher the precision.
  • Primary accelerator: The principal, highest concentration accelerator used in a vulcanizing system.
  • Processability: The relative ease with which raw or compounded rubber can be handled in rubber machinery.
  • Processing aid: A compounding material that improves the processability of a polymeric compound.
  • Radial clearance: The difference in the radial dimensions between the sealing surfaces of a radial seal.
  • Radicals: Atoms or polyatomic molecules with at least one unpaired electron.
  • RCA Clean: A multi-step wet chemical process to clean wafers before oxidation; named after RCA, the company that invented the procedure.
  • Reactive ion etching (RIE): An etching process that combines plasma and ion beam removal of the surface layer. The etchant gas enters the reaction chamber and is ionized. The individual molecules accelerate to the wafer surface. At the surface, the top layer removal is achieved by the physical and chemical removal of the material.
  • Recipe: A formula, mixing procedure, and any other instructions needed for the preparation of a product.
  • Recovery: The degree to which a rubber product returns to its normal dimensions after being distorted.
  • Reinforcement: The act of increasing the mechanical performance capability of a rubber by the incorporation of materials that do not participate significantly in the vulcanization process.
  • Release agent (mold): A substance applied to the inside surfaces of a mold or added to a material to be molded, to facilitate the removal of the product from the mold.
  • Resilience: The ratio of energy output to energy input in a rapid (or instantaneous) full recovery of a deformed specimen.
  • Resilience, impact: The ratio of output to input mechanical energy in a rapid deformation and recovery cycle of a rubber specimen.
  • Resistivity, volume: The ratio of the electric potential gradient to the current density when the gradient is parallel to the current in the material.
  • Retarder: A material used to reduce the tendency of a rubber compound to vulcanize prematurely.
  • Reticle: A reproduction of the pattern to be imaged on the wafer (or mask) by a step-and-repeat process. The actual size of the pattern on the reticle is usually several times the final size of the pattern on the wafer.
  • Reversion (vulcanization): Deterioration of vulcanizate properties that may occur when vulcanization time is extended beyond the optimum.
  • Rubber: A material that is capable of recovering from large deformations quickly and forcibly and can be, or already is, modified to a state in which it is essentially insoluble (but can swell) in a boiling solvent such as benzene, methyl ethyl ketone, or ethanol-toluene azeotrope.
  • Rubber hardness degree, international (IRHD): A measure of hardness, the magnitude of which is derived from the depth of penetration of a specified indenter into a specimen under specified conditions. The scale is so chosen that zero would represent a material showing no measurable resistance to indentation, and 100 would represent a material showing no measurable indentation.
  • Runner: The secondary feed channel for transferring material under pressure from the inner end of the sprue to the cavity gate.
  • Scanning electron microscope (SEM): A microscope used to magnify images as much as 50,000 times by means of scanning with an electron beam. The impinging electrons cause electrons on the surface to be ejected, and the ejected electrons are collected and translated into a picture of the surface.
  • Scarf joint: A connection made with two ends cut at an angle and overlapping.
  • Scorch: Premature vulcanization of a rubber compound.
  • Scorch, Mooney: The time to incipient cure of a compound when tested in the Mooney shearing disk viscometer under specific conditions.
  • Seal: Any material or device that prevents or controls the passage of matter across the separable members of a mechanical assembly.
  • Seal, O-ring: A product of precise dimensions molded in one piece to the configuration of a torus with circular cross-section, suitable for use in a machined groove for static or dynamic service.
  • Secondary accelerator: An accelerator used in smaller concentrations, compared to the primary accelerator, to achieve a faster rate of vulcanization.
  • Semiconductor: A material whose electrical resistivity is intermediate between that of conductors and insulators, in which conduction takes place by means of holes and electrons.
  • Set: Strain remaining after complete release of the force producing the deformation.
  • Shelf life: See storage life, shelf.
  • Shock load: The sudden application of an external force.
  • Shrinkage: 1) Decrease in volume of a seal in service due to extraction of fillers. 2) Decrease in volume of an elastomeric compound during molding.
  • Silicide: A compound of silicon with a refractory metal. Common silicide semiconductor films (used as interconnects) include titanium, tungsten, tantalum, and molybdenum.
  • Silicon dioxide (SiO2): A non-conducting layer that can be thermally grown or deposited on silicon wafers. Thermal silicon dioxide is commonly grown using either oxygen or water vapor at temperatures above 900°C.
  • Silicon nitride (Si3N4): A nonconductive layer chemically deposited on wafers at temperatures between 600° and 900°C.
  • Silicone rubber: Poly dimethyl siloxane elastomer.
  • Solubility: The ability or tendency of one substance to blend uniformly with another.
  • Sorption: The term used to denote the combination of absorption and adsorption processes in the same substance.
  • Specific gravity: The ratio of the weight of a given substance to the weight of an equal volume of water at a specified temperature.
  • Spew line: Line on the surface of a molded product at the junction of the mold parts.
  • Spin-on-glass (SOG): A dielectric suspended in a liquid solvent at room temperature, allowing the material to be spun onto a wafer. Most SOG films are siloxane polymers dissolved in alcohol-ketone solvents. After being spun on the wafer, the wafers must be baked to drive off the solvent.
  • Sputtering: A method of depositing a thin film of material on wafer surfaces. A target of the desired material is bombarded with radio frequency-excited ions which knock atoms from the target; the dislodged target material deposits on the wafer surface.
  • Squeeze: The compression of a seal, usually expressed as a percentage calculated by dividing the deformation by the original seal cross-sectional diameter.
  • Standard clean one: A mixture of ammonium hydroxide, hydrogen peroxide, and UPDI. The first step in the RCA Cleaning process, which is designed to remove organic material.
  • Standard clean two: A mixture of hydrochloric acid, hydrogen peroxide, and UPDI. The second step in the RCA Cleaning process, which is designed to remove metals and other inorganic material.
  • Static seal: A seal in which the sealing surfaces do not move relative to each other.
  • Steam oxide: Thermal silicon dioxide grown by bubbling a gas (usually oxygen or nitrogen) through water at 100°C.
  • Stepper: A machine that steps a reticle directly onto the wafer. A reticle can be produced at a lower defect level and with tighter dimensional control than an entire mask, resulting in wafer images having fewer defects. Alignment of reticle to wafer is accomplished by reflecting a laser beam through a special reticle pattern (alignment target) and off a corresponding pattern on the wafer.
  • Stiction: The increase in static friction resulting from prolonged seal compression.
  • Stiffness, bending: The force required to produce a bent configuration under specified conditions.
  • Stock: See compound.
  • Storage life, shelf: The period of time after production during which a material or product that is stored under specified conditions retains its intended performance capabilities.
  • Strain: The unit change, due to force, in the size or shape of a body referred to its original size or shape.
  • Stress: The intensity, at a point in a body, of the internal forces (or components of force) that act on a given plane through the point.
  • Stress relaxation: The decrease in stress after a given time at constant strain.
  • Stripping: Removal process; usually refers to photoresist.
  • Susceptor: A component of many equipment systems on which the wafer is placed. Frequently made of high-purity graphite.
  • Swelling: The increase in volume of a specimen immersed in a liquid or exposed to vapor.
  • Target: The material to be sputtered during the sputtering process.
  • Tear: Mechanical rupture initiated and propagated at a site of high stress concentration caused by a cut, defect, or localized deformation.
  • Tear strength: The maximum force required to tear a specified specimen, the force acting substantially parallel to the major axis of the test specimen.
  • Tensile set: The extension remaining after a specimen has been stretched and allowed to retract in a specified manner expressed as a percentage of the original length.
  • Tensile strength: The maximum tensile stress applied during stretching a specimen to rupture.
  • Tensile stress: A stress applied to stretch a test piece (specimen).
  • Tension fatigue: Fracture, through crack growth, of a component or test specimen subjected to repeated tensile deformation.
  • Tension set: The strain remaining after a test piece or product has been stretched and allowed to retract.
  • Terpolymer: A polymer formed from three monomer species.
  • Thermal carbon black: Type of carbon black produced under controlled conditions by the thermal decomposition of hydrocarbon gases in the absence of air or flames.
  • Thermal degradation: Irreversible and undesirable change in the properties of a material due to exposure to heat.
  • Thermal diffusion: A process by which dopant atoms diffuse into the wafer surface by heating the wafer in the range of 1,000°C and exposing it to vapors containing the desired dopant.
  • Thermoplastic elastomer (TPE): A diverse family of rubber-like materials that, unlike conventional vulcanized rubbers, can be processed and recycled like thermoplastic materials.
  • Topography: The characteristic of a surface referring to its degree of flatness and smoothness.
  • Torr: Pressure unit; international standard unit replacing the English measure, millimeters of mercury (mm-Hg).
  • TR-10: A test method for approximating the low-temperature capabilities of an elastomer.
  • Transistor: A semiconductor device that uses a stream of charge carriers to produce active electronic effects. The name originated from the electrical characteristic of transfer resistance.
  • Transition, first order: A reversible change in phase of a material; in the case of polymers, usually crystallization or melting.
  • Transition, glass (Tg): The reversible physical change in a material from a viscous or rubbery state to a brittle, glassy state.
  • Ultrapure deionized water (UPDI): A highly purified water in which all charged species of ionizable organic and inorganic salts have been removed.
  • Ultraviolet (UV): Electromagnetic radiation in the wavelength 4—400 nanometers.
  • UV stabilizer: A compounding material that, through its ability to absorb ultraviolet radiation and render it harmless, retards the deterioration caused by sunlight and other UV light sources.
  • Vacuum evaporation: A deposition technique whereby the deposited gas results from an evaporation process.
  • Van der Waals force: An attractive force between two atoms due to a fluctuating dipole moment in one molecule inducing a dipole moment in the other molecule, which then interact.
  • Vapor pressure: The pressure of the vapor in equilibrium with its liquid or solid phase.
  • Virtual leak: An apparent leak in a vacuum system that is often traceable to some internal release of occluded and/or sorbed gases.
  • Viscoelasticity: A combination of viscous and elastic properties in a material with the relative contribution of each being dependent on time, temperature, stress, and strain rate.
  • Viscosity: The resistance of a material to flow under stress.
  • Viscosity, Mooney: A measure of the viscosity of a rubber or rubber compound determined in a Mooney shearing disk viscometer.
  • Void, cellular material: A cavity unintentionally formed in a cellular material and substantially larger than the characteristic individual cells.
  • Volatilization: Also known as vaporization, the conversion of a chemical substance from a liquid or solid state to a gaseous or vapor state.
  • Volt: A unit of electromotive force or difference in electric potential.
  • Volume swell: The increase in dimension caused by the absorption of a fluid.
  • Vulcanizate: The product of vulcanization, a cross-linked rubber.
  • Vulcanization: An irreversible process during which a rubber compound, through a change in its chemical structure (for example, cross-linking), becomes less plastic and more resistant to swelling by organic liquids, while elastic properties are conferred, improved, or extended over a greater range of temperature.
  • Vulcanizing agent: Compounding material that produces cross-linking in rubber.
  • Vulcanizing system: The combination of a vulcanizing agent and, as required, accelerators, activators, and retarders used to produce the desired vulcanization characteristics or vulcanizate characteristics.
  • Wafer flat: Flat area(s) ground onto the wafer’s edges to indicate the crystal orientation of the wafer structure and the dopant type.
  • Warm-up: The reduction in viscosity of a rubber or rubber mix, by mechanical work and heat, to render it suitable for further processing.
  • Wavelength: The length of the wave to complete one cycle.
  • Wicking: Transmission of a gas or liquid, due to a pressure differential or capillary action, along fibers incorporated in a rubber product.
  • Wiper ring: A device designed to keep out foreign material.
  • Yield point: That point on the stress-strain curve, short of ultimate failure, where the rate of stress with respect to strain goes through a zero value and may become negative.
  • Yield strain: The level of strain at the yield point.
  • Yield stress: The level of stress at the yield point.
Scroll to Top