PCB Glossary

Using capacitors to pass AC signals while blocking DC between circuits.

The copper pad area surrounding a drilled hole, critical for reliable connections.

HDI technology where all layers can interconnect with micro-vias, without traditional through-holes.

Machine vision system that inspects PCBs for defects by comparing images against reference designs.

Ratio of hole depth to diameter, affecting plating quality in through-holes and vias.

Isola's thermoset alternative to PTFE for automotive radar at 77 GHz.

Removing unused via stub portions to reduce signal integrity issues at high frequencies.

Fracture in via plating wall caused by thermal cycling stress.

Surface-mount package with solder balls arranged in a grid pattern on the underside.

Process of removing old solder balls from a BGA and attaching new ones for reuse or repair.

Via connecting an outer layer to one or more inner layers without going through the entire board.

Test methodology using on-chip logic to verify connections without physical probe access.

PCB flatness deviations measured as warpage, critical for surface-mount assembly.

High-performance laminate material with excellent thermal stability and low dielectric constant.

Process of adding layers to a core through sequential lamination in HDI fabrication.

Via connecting inner layers without reaching either outer surface.

Software for designing PCB layouts, schematics, and generating manufacturing files.

Electrochemical failure mode where copper filaments grow along glass fibers.

Software that converts PCB design data into manufacturing instructions.

Half-holes at PCB edges that form solderable connections for module attachment.

The impedance a transmission line presents to a signal, determined by geometry and materials.

Impedance a transmission line presents to a traveling wave, determined by geometry and materials.

Minimum spacing between conductive features, determined by voltage and manufacturing limits.

Thin protective film applied to assembled PCBs to shield against environmental hazards.

PCB traces designed and manufactured to a specific impedance value with tolerance.

Transmission line with signal trace flanked by ground on the same layer.

Large area of copper filling unused space on a PCB layer, typically connected to ground or power.

Copper thickness specified as weight per square foot, where 1 oz = 35 µm (1.4 mil).

Flexible polyimide film laminated over flex circuit traces instead of solder mask.

Unwanted coupling of signals between adjacent traces.

IC package where the package size is no more than 1.2x the die size.

Rate at which a material expands when heated, measured in ppm/°C.

Providing local energy storage to supply transient current demands from ICs.

Process of separating individual PCBs from a manufacturing panel after assembly.

Measure of signal energy lost as heat in a dielectric material, also called loss tangent.

Design practices that ensure a PCB can be manufactured reliably and cost-effectively.

Electrically insulating material between conductive layers in a PCB.

Two traces carrying complementary signals, providing noise immunity for high-speed signals.

Measure of a material's ability to store electrical energy, affecting signal speed and impedance.

Automated verification that a PCB design meets manufacturing constraints.

Creating holes in PCBs mechanically or with lasers for vias and through-holes.

Copper plating on PCB edges for grounding, shielding, or electrical contact.

Chemical deposition of metal without external electrical current, for uniform coverage.

Metal deposition using electric current, building up copper thickness on PCB features.

Capacitance created in PCB inner layers using high-Dk dielectric materials.

Resistor fabricated directly into PCB inner layers using resistive foil or paste.

Ability of equipment to function without causing or being affected by EMI.

Unwanted electromagnetic energy that can disturb electronic equipment operation.

Three-layer surface finish adding palladium for improved wire bonding and corrosion resistance.

Surface finish with nickel barrier and thin gold layer, providing flat pads and good shelf life.

Routing signals out from under BGA and CSP components to reach vias or traces.

Chemical removal of unwanted copper to define traces and features.

Routing from component pads to vias that connect to other layers.

High-capacitance laminate material for embedded capacitance layers.

Inductive component that absorbs high-frequency noise while passing DC and low frequencies.

Impedance variation caused by periodic glass/resin structure in PCB laminates.

Reference mark on a PCB used by pick-and-place machines for alignment.

PCB built on flexible polyimide substrate that can bend and flex.

Electrical test method using moving probes for prototype and low-volume testing.

The copper pad pattern on a PCB that matches a component's physical package.

Standard glass-reinforced epoxy laminate used in most PCBs.

Isola's low-loss high-Tg FR-4 variant with improved signal integrity over standard 370HR.

Testing an assembled PCB by powering it and verifying it performs its intended function.

Standard file format for PCB manufacturing data, describing copper layers, solder mask, and silkscreen.

Specification of fiberglass weave pattern and weight used in laminate reinforcement.

Continuous copper layer providing current return path and reference for signals.

PCB materials without chlorine, bromine, and other halogenated flame retardants.

Surface finish where boards are dipped in molten solder then leveled with hot air knives.

RoHS-compliant HASL finish using lead-free solder alloys instead of traditional tin-lead.

PCB technology using micro-vias and fine lines to achieve higher wiring density.

Laminate with elevated glass transition temperature for lead-free assembly and thermal stress.

Ultra-smooth copper foil with <2 µm surface roughness for high-speed signal integrity.

Isola's workhorse low-loss laminate for high-speed digital designs up to 56 Gbps.

Electrical test using a bed-of-nails fixture to verify component presence and values.

Thin gold layer deposited by chemical displacement reaction, used in surface finishes.

Opposition to alternating current flow, measured in ohms, critical for high-speed signal integrity.

Signal power lost as it travels through a PCB transmission line.

Global trade association that develops standards for electronics manufacturing.

IPC standard classification for dedicated service electronic products.

IPC standard classification for high-reliability electronic products.

Major PCB laminate manufacturer known for FR-4 and high-speed materials.

Taiwanese laminate manufacturer with strong high-speed and halogen-free product lines.

Hong Kong-based manufacturer and the world's largest producer of copper-clad laminates.

Cured copper-clad material forming the rigid base layers of a PCB.

Bonding PCB layers together with heat and pressure to form a solid multilayer structure.

Using focused laser energy to create micro-vias in PCB layers.

Number of copper layers in a multilayer PCB.

Soldering materials and processes without lead, required for RoHS compliance.

Ratio of energy lost to energy stored in a dielectric, equals dissipation factor.

Package or substrate containing multiple integrated circuits in a single unit.

Panasonic's high-speed laminate series, the industry standard for 10-112 Gbps digital applications.

Laser-drilled via ≤150 µm diameter, typically connecting adjacent layers in HDI PCBs.

Cross-sectional sample of PCB features for quality inspection and analysis.

Transmission line with a trace on the outer layer referenced to a ground plane below.

RF signals from ~300 MHz to ~300 GHz, requiring specialized PCB materials.

PCB with three or more copper layers bonded together with dielectric.

Drilled hole without copper plating, used for mounting hardware or component clearance.

Intelligent CAD-to-CAM data format containing complete PCB manufacturing information.

Resistive foil material for creating embedded resistors in PCBs.

Water-based organic coating that protects copper from oxidation until soldering.

Frame of waste material around a PCB panel that holds boards together during manufacturing.

Arranging multiple PCBs on a larger panel for efficient manufacturing.

Board with conductive traces that mechanically supports and electrically connects electronic components.

Complete system delivering power from supply to ICs, including planes and decoupling.

Automated machine that places surface-mount components onto PCB pads.

Transformer using PCB windings instead of wound wire, enabling low-profile designs.

High-temperature polymer used as flexible PCB substrate and high-reliability rigid laminate.

Dedicated copper layer for power distribution to components.

Pre-impregnated fiberglass cloth that bonds layers together during lamination.

Low-loss fluoropolymer material used in RF and microwave PCBs, commonly known as Teflon.

Drilled hole with copper plating providing electrical connection between layers.

DuPont's dominant flex circuit material family based on Kapton polyimide.

Leadless surface-mount package with contacts on the bottom and exposed thermal pad.

Surface-mount IC package with leads extending from all four sides.

Copper foil pre-coated with resin, used for HDI build-up layers.

Signal energy bouncing back from impedance discontinuities in a transmission line.

Heated chamber that melts solder paste to form permanent solder joints.

Assembly process where solder paste melts in an oven to attach surface-mount components.

Equipment for removing and replacing surface-mount components after initial assembly.

Electromagnetic signals from ~3 kHz to ~300 GHz, requiring special PCB design considerations.

Taconic's ceramic-filled PTFE laminate that processes like FR-4 for commercial microwave.

Wireless technology using electromagnetic fields to identify and track tags attached to objects.

PCB combining rigid board sections with flexible interconnect regions.

Rogers ceramic-filled PTFE laminate optimized for 77 GHz automotive radar.

Rogers hydrocarbon ceramic laminate that processes like FR-4 for RF applications to 10 GHz.

Rogers' most widely used RF laminate, the industry standard from 1 GHz to 77 GHz.

Major manufacturer of high-frequency PCB laminates, especially PTFE-based materials.

EU directive restricting lead, mercury, cadmium, and other hazardous materials in electronics.

Rogers' gold-standard PTFE laminate with the lowest loss for aerospace and satellite applications.

Machine that applies solder paste to PCB pads through a stencil.

Automated soldering process for through-hole components on boards with SMT on the opposite side.

Multiple lamination cycles used to create buried vias and HDI structures.

Resistance of a thin film measured in ohms per square, independent of square size.

Major Chinese laminate manufacturer offering FR-4 through high-speed materials.

Quality of electrical signals, ensuring they arrive at receivers in usable condition.

Printed legend layer showing component designators, logos, and assembly markings.

Component designed to mount directly on the PCB surface without through-hole leads.

PCB construction where solder mask is applied directly over copper without a surface finish underneath.

Assembly method using automated placement of components on PCB surface pads.

Unintended solder connection between adjacent pads or traces.

Protective coating over copper traces, leaving pads exposed for soldering.

Mixture of powdered solder and flux applied to PCB pads before component placement.

Automated inspection of solder paste deposits before component placement.

Flattened fiberglass weave providing more uniform dielectric constant.

Micro-vias placed directly on top of each other through multiple layers.

The arrangement of copper layers, cores, and prepregs defining a PCB's structure.

Micro-vias offset from each other on successive layers to reduce filling requirements.

Thin metal sheet with apertures used to deposit solder paste onto PCB pads.

Transmission line with a trace on an inner layer sandwiched between two ground planes.

Isola's ultra-low-loss laminate for 100 Gbps+ applications with performance stable to 100 GHz.

Manufacturer of high-frequency PCB laminates, particularly PTFE-based materials.

Change in resistance per degree of temperature change, expressed in ppm/°C.

Temperature at which PCB laminate begins to chemically break down.

Measurement technique for verifying controlled impedance and locating discontinuities.

Gradual widening of a trace where it meets a pad or via to improve reliability.

Impedance-matching component at transmission line end to absorb signal and prevent reflections.

Sample structures on PCB panels for measuring impedance, plating, and other parameters.

Custom hardware interface that connects test equipment to a PCB for automated testing.

Temperature at which a laminate transitions from rigid to soft, affecting thermal reliability.

Repeated temperature fluctuations that stress PCB materials and solder joints over time.

Design techniques and materials for controlling heat in electronic assemblies.

Via designed to conduct heat from a component to inner planes or the opposite board surface.

Component attachment using leads inserted through holes and soldered on the opposite side.

Taconic's lowest-loss PTFE laminate for commercial satellite and radar applications.

Rogers ceramic-hydrocarbon thermoset series with Dk options from 3.27 to 12.85.

Assembly defect where a component stands on end due to unbalanced solder forces.

Copper conductor on a PCB that carries electrical signals or power between components.

Safety certification organization that tests and certifies PCB flammability and safety.

Epoxy material dispensed under BGAs and flip chips to improve thermal cycling reliability.

High-energy light used in PCB manufacturing for imaging, curing, and inspection.

Partial-depth cuts on PCB panels that allow boards to be snapped apart.

UK/Asia laminate manufacturer known for thermal management and halogen-free materials.

Completely filling vias with conductive or non-conductive material.

Filling vias with non-conductive epoxy to seal and planarize the surface.

Unused portion of through-hole via extending past the signal layer.

Covering vias with solder mask to protect from solder and contamination.

Via placed directly in a component pad, typically filled and planarized for SMD soldering.

Assembly process where PCBs pass over a wave of molten solder for through-hole components.

Non-destructive inspection using X-rays to view hidden solder joints under BGAs and QFNs.

Thermal expansion perpendicular to the PCB surface, critical for via reliability.