Flex & Rigid-Flex Circuits Glossary

Access Hole:

A hole in a layer of dielectric material that provides access to a land on a conductive layer of the flexible circuit.

Adhesions (pressure sensitive tape):

The bond produced by contact between pressure-sensitive adhesive and a surface.

Adhesive:

A substance such as glue or cement used to fasten objects together.

Array:

A group of elements or circuits arranged in rows and columns on a panel.

Artwork:

An accurately-scaled configuration that is used to produce the conductor pattern.

Base Material:

The insulative material upon which a conductive pattern may be formed. The base material may be rigid or flexible, or both.

Bend Ratio:

A relationship between the thickness of material bent to the radius over which it is bent.

Bending Resistance:

The ability of a material to withstand repeated bending to specified parameters without producing cracks or breaks in excess of the specification allowance.

Bonding Layer:

An adhesive layer used in bonding together plies of dielectric and conductive materials during lamination.

Cap Lamination:

A process of making multilayer printed boards with surface layers of metal-clad laminates bonded in a single operation.

Conductor Layer:

The total conductive pattern formed on one side of a single layer of base material.

Coverfilm (Coverlayer):

A film of dielectric material with adhesive which is bonded over the etched conductor runs to insulate them.

Dielectric Strength:

The maximum voltage that a dielectric can withstand under specified conditions without resulting in a voltage breakdown, usually expressed as volts per unit of dimension.

Dynamic Flex:

A flexible circuit designed to move during operation.

Edge Spacing:

The distance of an etched feature from the edges of a printed board.

Flexible Multilayer Printed Board (Type 3):

Multi-layered printed board made of only flexible materials. Different areas of the multilayer printed board may have different numbers of layers and thickness.

Flexible Printed Board (Circuit):

A printed board made only of flexible materials.

Insulation Resistance:

The electrical resistance of an insulting material that is determined under specific conditions between any pair of contacts, conductors or grounding devices in various combinations.

Polyimide:

The synthetic polymer that has more than two imide radicals in the main chain.

Prepreg:

A sheet of material that has been impregnated with a resin cured to an intermediate stage (i.e. B-staged resin).

Sequential Lamination:

The process of manufacturing multilayer printed circuit boards in which multiple double-sided layer stacks with interconnecting holes between conductive patterns on both sides are laminated or combined, after which additional layers are attached to the partially completed board stack up.

Static Flex (Flex-To-Install):

A flexible printed board designed to be bent for installation purposes only (not in operation).

Steel Rule Die:

A piece of tooling made from a hardwood base with hand-formed steel rule placed into a laser burned path which is used to profile portions of or the entire final shape of a flex circuit.

Stiffener Board:

A material fastened to the surface of a flexible printed board to increase its mechanical strength.

Thermal Cure:

A chemical reaction using heat energy that hardens organic substances such as adhesives and coating materials.

Window (in the coverlayer):

An opening in the dielectric of a flexible printed board that exposes conductors.