PCB DEFINITIONS

Annular Ring That portion of conductive material completely surrounding a hole.

Base Material The insulating material upon which a conductive pattern may be formed. (The base material may be rigid or flexible, or both, It may be a dielectric or insulated metal sheet.)

Blister Delamination in the form of a localized swelling and separation between any of the layers of a larninate base material, or between base material and conductive foil or protective coating.

Bow The deviation from flatness of a board characterized by a roughly cylindrical or spherical curvature such that, if the board is rectangular, its four corners are in the same plane,

Conductive Foil A thin sheet of metal that is intended for forming a conductive pattern on a base material.

Conductor Pattern The configuration or design of the conductive material on a base material. (This includes conductors, lands, vias. heatsinks, and passive components when these are an integral part of the printed board manufacturing process.)

Crazing An internal condition that occurs in reinforced laminate base material whereby glass fibers are separated from the resin at the weave intersections. (This condition manifests itself in the form of connected white spots or crosses that are below the surface of the base material. It is usually related to mechanically-induced stress,)

Delamination A separation between plies within a base material, between a base material and a conductive foil, or any other planar separation within a multilayer printed board.

Dent A smooth depression in conductive foil that does not significantly reduce the foil's thickness.

Etched Printed Board A board having a conductive pattern that was formed by the chemical removal of unwanted portions of a conductive foil.

Fiducial Mark A printed board artwork feature (or features) that is created in the same process as the printed board conductive pattern and that provides a common measurable point for component mounting with respect to a land pattern or land patterns.

Haloing Mechanically-induced fracturing or delamination, on or below the surface of a base material, that is usually exhibited by a light area around holes or other machined features.

LPI Liquid photoimageable.

Measling A condition that occurs in laminated base material in which internal glass fibers are separated from the resin at the weave intersection. (This condition manifests itself in the form of discrete white spots or crosses that are below the surface of the base material. It is usually related to thermally-induced stress.)

Multilayer Printed A multilayer printed board with two or more printed circuit layers.
Circuit Board

Overhang The sum of outgrowth and undercut. (If undercut does not occur, the overhang is the same as the outgrowth.)

Pinhole An imperfection in the form of a small that penetrates entirely through a layer of material.

Pit A small hole- that does not pass through the entire thickness of a conductive foil.

Plated-Through Hole A hole with plating on its walls (hat makes an electrical connection between conductive patterns on internal layers, external layers, or both, of a printed board.

Printed Circuit A conductive pattern that is composed of printed components, printed wiring, or a combination thereof, that is formed in a predetermined arrangement on a common base. (That is also a generic term that is used to describe a printed board (fiat is produced by any of a number of techniques.)

Raggedness Irregularities along the edges of a conductor pattern.

Register Positional accuracy of a PCB conductive layer.

Registration The degree of conformity of the position of a pattern (or portion thereof, a hole, or other feature to its intended position on a product.

Registration, Solder Mask
The positional accuracy of the solder mask to the external solder and
component side pads.

Resin-Starved Area The location in a printed board that does not have a sufficient amount of resin to completely wet out the reinforcing material. (Evidence of this condition is often in the form of low-gloss dry spots or exposed fibers.)

Scratch A narrow furrow or grove in a surface.(it is usually shallow and caused by the marking or rasping of the surface with a pointed or sharp object.)

SMD Surface Mount Device. A leaded or leadless component (device) that is capable of being attached to a printed board by surface mounting.

SMOBC Solder Mask Over Bare Copper. A method of fabricating a PCB which results in the final metallization being copper with no other protective metal; but the non-soldered areas are coated by a solder mask exposing only the component terminal areas. This eliminates tin-lead under the solder mask.

SMT Surface Mount Technology.

Spurious Metal Unwanted metal, usually copper, that remains on a base material after chemical processing. Also referred to as "Extraneous Metal".

Supported Hole A hole in a printed board that has its inside surfaces plated or otherwise reinforced.

True Position The theoretically-exact location for a feature or hole that is established by basic dimensions.

Twist The deformation of a rectangular sheet, that occurs parallel to a diagonal across its surface, such that one of the corners of the sheet is not in the plane that contains the other three corners.

Undercut, After Fabrication
The distance, measured parallel to the surface of a printed board, from the outer edge of a conductor (excluding overplating and coatings) to the maximum point of the indentation on the same edge of the conductor.

Undercut, InProcess
The distance, measured parallel to the surface of a printed board, from the outer edge of a conductor (including etch resist) to the maximum point of the indentation on the same edge of the conductor.

Unsupported Hole A hole in a printed board that does not contain plating or other type of conductive reinforcement.

Warp The deviation from flatness of a board characterized by a roughly cylindrical or spherical curvature such that, if the board is rectangular, its four corners are in the same plane.