ABSTRACT
Q/square and more than IO9 Q/ square.
ARRAY: A group of elements or circuits arranged in rows and columns on one substrate. ARTWORK: The accurately scaled configuration or pattern produced usually at an enlarged ratio, to enable the product to be made therefrom by photographic reduction to a 1 : 1
working pattern; layouts and photographic films which are created to produce the working thick-film screens and thin-film masks. ARTWORK MASTER: A dimensionally accurate imaged pattern (usually mylar or glass) used to manufacture production masters for use in photoimaging processes. As-FIRED: Values of thick-film resistors or smoothness of ceramic substrates as they come out of firing furnace and, respectively, prior to trimming and polishing (if required). ASPECT RATIO: The ratio between the length of a film resistor and its width; equal to the number of squares of the resistor. ASSEMBLY: A film circuit to which discrete components have been attached. It might also show the assembly of one or more film circuits which may include several discrete components. ASSEMBLY DRAWING: A drawing showing all the components and interconnections mounted or soldered to the film circuit in their proper positions. It might also show the assembly of one or more film circuits which may include several discrete components. ATTACH: An inclusive term in hybrid assembly, to denote permanent joining by means of intermediary material(s). Examples are attaching a substrate to case or a device to a substrate. ATTACH, DEVICE TO SUBSTRATE:
The process of fastening devices, components, or elements of a hybrid to a substrate in permanent bond at designated locations, properly oriented. The process varies accordint to physical configurations. Soldering is preferred
both. BEADS: See glass preforms. BEAM LEAD DEVICE: An active or passive chip component possesing beam leads as its primary interconnection and mechanical attachment means to a substrate. BELLOWS CONTACT: A flat folded spring connector contact providing uniform spring rate over the mating contact tolerance range. BERYLLIA OR BERYLLIUM OXIDE
(Beo): A substrate material widely used in power hybrids where high thermal conductivity is needed. BIFURCATED CONTACT: A flat lengthwise-slotted contact that permits independent contact points. BINDERS: Materials added to thickfilm compositions and unflred substrates to give sufficient strength for prefire handling. BLACK OXIDE: A technique for making matched seals by forming a controlled thickness oxide on each of the mating surfaces of a package prior to sealing. BLANK: A rough-dimensioned printed board cut from a panel of base material that is either unprocessed or partially processed. BLEEDING: The lateral spreading or diffusion of printed film into adjacent areas, beyond the geometric dimensions of the printing screen. This may occur during drying, or firing. BLENDING: Different viscosities of the same types of materials may be blended together to achieve intermediate viscosities. This term is also applied to resistive inks that can be blended with each other to achieve in-
termediate resistivities. BLIND VIA: An interstitial via connecting a top conductive layer with one or more inner conductive layers. BLISTER: Raised parts of a conductor or resistor formed by the outgassing of the binder or vehicle during the firing cycle. BLOCK: TO plug-up open mesh in a screen to prevent resistor or conductor pastes from being deposited in unwanted areas. BLOCK DIAGRAM: A circuit diagram in which the essential units of the functional system are drawn in the form or blocks and the relationship between blocks is indicated by appropriate connecting lines. BLOCK-OFF: See block. BLOW HOLE: A surface anomaly formed by outgassing as solder solidifies. BOAT: A container for materials to be vacuum-evaporated or fixed. BOILING POINT: The temperature of a liquid at which its vapor pressure is equal to the pressure of the atmosphere surrounding the fluid. BOMB: A chamber for applying various levels of positive or negative pressure on a package or component. BOND: An interconnection which performs a permanent electrical and/or mechanical function. BOND DEFORMATION: The change in the form of the lead produced by the bonding tool, causing plastic flow, in making the bond. BOND ENVELOPE: The range of bonding parameters over which acceptable bonds may be formed. BOND INTERFACE: The interface be-
loy. To join metals with a nonferrous filler metal at temperatures above 427°C. BRAZING: Also called hard soldering. Similar to soldering, it is the joining of metals with a nonferrous filler metal at temperatures above427°C. BREAK LOAD: See bond strength. BREAKAWAY: In screen printing the distance between the upper surface of the substrate and the lower surface of the screen when the screen is not deflected by the squeegee. BREAKDOWN VOLTAGE: The voltage threshold beyond which there is a marked (almost infinite rate) increase in electrical current conduction. BRIDGING: A defect condition, where the locallized separation between any two conductor lines (paths, traces) is reduced to less than the minimum allowable. In the extreme, it becomes a short. Bridging may be caused by misalignment, screening, solder splash, smears, or attached foreign material. B-STAGED RESIN (B-STAGE): A partially cured resin which is used in the lamination process (see also prepreg). BUGGING HEIGHT: The distance between the hybrid substrate and the lower surface of the beam lead device which occurs because of deformation of beam leads during beam lead bonding. BULK CONDUCTANCE: Conductance between two points of a homogeneous material. BURIED VIA: An interstitial via connecting inner conductive layers of a printed board, or multilayer substrate but not extending to either surface.
