Terms Defined

Alternating Current (AC) – A current whose polarity alternates from positive to negative over time. Alteration rate is measured in cycles per second – or Hertz (Hz).

Alloy – a mixture of 2 or more materials or metals.

Alumina - Aluminum Oxide, a material often used for substrates.

Amp/Ampere – the basic unit of current flow.

Amplifier – a device which generates a high power signal based on the information supplied by a lower power signal.

Amplitude – the loudness of sound waves and electrical signals. Measured in decibels or volts.

Annealing - A method of method of toughening certain metals and decreasing their brittleness by heating and then allowing them to cool slowly - relieving stresses in the material.

Arcing – condition that occurs and causes failure in a DWV or IR test.

Attenuation – the decrease of a signal’s amplitude level over any distance during transmission or through purposed designed attenuators – attenuation measures signal loss in decibels (dB).

AU/GE - A solder of Gold and Germanium - used in Low Temperature Brazing - 356 Degree Eutectic Temperature.

Au/Sn - A solder of Gold and Tin - used in Low Temperature Brazing - 280 Degree Eutectic Temperature.

Bandwidth – the measure of a range of frequencies containing an upper and lower limit.

Bathtub - Nickname for a Plug-In style package.

Battery Header – GTMS assembly used on hermetic high-reliability energy storage cells used to power military and commercial devices – general types – Lithium Primary, Medical, and Thermal.

BeO – Beryllia Oxide – used as a base material for hybrid packages and semi-conductor chips – Thermal conductivity of around 250 W/MoK – CTE of 6.4 ppm/Co

Beryllia - Name used for Beryllium Oxide - a material sometimes used for substrates.

Blister - An uplifting of the primary or secondary layer of plating on a package - often detected through heat exposure.

Bonding Area - Normally, the upper surface of the internal lead extension.

Brittle – easily shattered or broken.

BT – (Cu-Sil) Copper Silver Braze material – melting point of 780 degrees Celsius.

Burr – a rough edge or ridge left on metal or other materials caused by cutting or drilling.

Bus – a pathway that connects devices, enabling them to communicate. May be digital or analogue, including power and earth (ground).

CRES – Corrosion Resistant Steel - Stainless

CRS - Cold Rolled Steel.

Coining - A metal forming process similar to stamping except that the metal is cold flowed in addition to being sheared.

Compression Seal - A glass-to-metal seal involving a mismatch of the thermal expansion rates of the materials used. During the cooling stage, after the firing process, the outer member shrinks in on the glass, which in turn shrinks in on the pin or lead. The tremendous compressive forces created result in hermeticity. Also known as a mechanical bond seal.

Copper-Cored Pin - A round pin formed of sealing alloy around a central core of copper.

Counterbore - A round, flat bottomed depression in an eyelet.

Cross-Section - The most accurate method of measuring the thickness of plating. Also can be used to perform hermeticity failure analysis.

CTE – Co-Efficient of Thermal Expansion – a materials fractional change in length for a given unit change in temperature.

DB – Decibel – defined as the smallest variation of volume detectable by ear.

Direct Current (DC) – A current flow which is steady with time, and flows in one direction only.

Dielectric - An insulating material - ceramic or glass – or medium that does not conduct electricity and that can sustain an electric field.

Diode – a semi-conductor device that converts alternating current to direct current.

DIP - Dual In-line package.

Ductile – capable of being stetched, drawn, or hammered without breaking – not brittle.

DWV – Dielectric Withstanding Voltage – voltage that can be applied to a designated spot between the electrode and the lead/pin for a minute in a dielectric voltage test. Used to measure voltage breakdown point.

Dye Penetrant - Chemical used to analyze leak paths on a non-hermetic part.

Electroless – Describes an autocatalytic plating process that does not require an electric current to flow through the work piece in order for plating to be deposited

Electrolytic –capable of conducting an electric current. Often used to describe a plating process that requires an electric current to flow through the work piece in order for plating to be deposited

End Seals (Capacitor End Seals) – GTMS assembly used to both store electrical energy (charge) and restrict/permit the flow of DC and AC current depending on the capacitance and frequency.

Eutectic – The invariant point for a substance at which change, either with the addition or removal of heat, results in an increase or decrease of the proportion of liquid to solid phases, without change in temperature.

Exothermic - A type of protective gas atmosphere formed by “cracking” natural gas.

Ferrous – of, containing, or derived from Iron.

FET – Field Effect Transistor

Filters – GTMS assemblies used to eliminate unwanted frequencies from an electronic signal.

Flange - A projecting rim or collar on a package base or lid.

Flux – a substance used to aid in the joining of 2 materials together – generally associated with the brazing or soldering process

Frequency – the rate at which an alternating current changes in a cyclical manner from positive to negative and back again (one cycle). The basic unit of measure is the Hertz (Hz), which equates to one cycle per second.

Heat Sink - A device that lowers thermal impedance and helps to dissipate heat from within the package.

HTCC – High Temperature Co-fired Ceramic

Impedance – a load applied to an amplifier (or other source) which is not a pure resistance. This is to say that its loading characteristics are frequency dependent. Impedance consists of some value of resistance in conjunction with capacitance and/or inductance.

Internal Height - The depth of the internal cavity of the package.

Integrated Circuit – a collection of active and passive devices (ex transistors and resistors) mounted on a single slice of silicon and packaged as a single component. Ex’s are operational amplifiers, CPU’s, random access memory, etc..

IR – Insulation Resistance

Kovar – Iron Nickel Alloy with the addition of Cobalt as a hardener.

Lapping - The process of using a rotating disk with an abrasive to grind or polish metal or glass.

Laser – Light amplification by Stimulated Emission of Radiation – made with Gas or semiconductors. Laser light is coherent, meaning that the emitted light waves are in phase, which gives the light a strange appearance since our eyes were never designed to observe coherent light.

LDMOS – Laterally Diffused metal oxide semiconductor

LTCC – Low Temperature Co-Fired Ceramic

Matched Seal - A GTMS in which all of the components have approximately the same rate of thermal expansion and therefore expand and contract at approximately the same rate of speed. Hermeticity is achieved by a molecular bond between the glass and metals. Also known as a chemical or molecular bond seal.

Metallization - A film of metal on the surface of another material - the other material is usually ceramic.

Microfinish - A plated finish which is one of uniform thickness to a microinch and entirely non-porous.

MOSFET – Metal Oxide Semiconductor Field Effect Transistor – electronically vary’s the width of a channel along which charge carriers (electrons or holes) flow.

Photoresist – a substance that can be made to form a tough film by photographic process, used to mask electrical circuits before chemical etching.

Pin-Out - slang for pin pattern.

Plating - Platings normally used on hybrid circuit packages are gold, nickel, or tin.

Pitch - The same as center to center spacing - pin to pin.

Power Package - A package - usually a flat pack style - having a base made of a thermal management material and large diameter leads - usually CU-Cored.

Preforms - Term referring to the medium used to attach 2 materials together – examples of performs: glass, ceramic, copper, copper silver-BT, Au/SN, Au/GE, Sn/Pb, and many others.

Precipitate – a substance that is caused to become insoluble by heat or chemical reagent and separate out from a solution.

Pre-Oxidizing - A process in which a controlled oxide is grown on the surface of the Kovar or other metal before glass sealing.

Radial – branching out in all directions from a common center.

Reducing Atmosphere - A protective atmosphere which prevents oxidation of metal parts while they are being fired.

Resistance Weld package - A package which is sealed by resistance welding the entire perimeter simultaneously.

RF – Radio Frequency

Refractory – resistant to heat, hard to melt.

Resistor – A device used in an electrical circuit to oppose (impede or resist) the flow of an electric current.

Rolloff - A rounded or pulled down condition on the corners of Flatpack frames - caused in the blanking and drawing operations of the stamping process.

Seal Surface - The upper flat plane of a flat package where the lid/cover is attached.

Seam Seal - A method of solder sealing packages using a seam welder. Two opposite points of the perimeter are sealed simultaneously.

Selective Plating - A process through which different platings are deposited on two or more portions of the package. Can be achieved by wiring or masking.

Sensor Headers – GTMS assemblies used in the monitoring and/or detection of a variety of mediums including: gas, fluids, temperature, current, force, strain, airflow, pressure, proximity, and moisture.

Shot – enough material for one cycle of a molding or casting machine.

Sinter – the process of combining/fusing metals, (usually with pressure and temperature) by exposing them to a temperature just below their melting point – usually used to “fire in” Nickel plating

Squibs (Initiators) – a small electrically initiated pyrotechnic charge, similar to a match head though faster burning, used to ignite propellant charges or generate gas to drive a mechanical component.

Standoff - A device that elevates a package above it’s mounting surface - metal, glass, or ceramic.

Thermal Conductivity - The rate at which a material conducts heat.

Thermal Expansion – Also known as CTE (see above) - the coefficient of thermal expansion is a measurement of the rate at which a given material expands as heat increases.

Transistor – an electronic device that controls current flow without use of a vacuum.

Wall Height - Usually refers to the depth of the internal cavity of a package.

Wall Thickness - The measurement of the thickness of the vertical portion of the package.

Wire Bonding - The most common method of making the electrical connection from the substrate to the leads - 3-types - Thermal Compression, Ultrasonic, and Pulse.