PCBsubstraadid

PCBsubstraadid, often referred to in English as PCB substrates, are the base materials used to build printed circuit boards. They provide electrical insulation for copper traces, mechanical support, and contribute to thermal management. Substrates are bonded with copper foil to form copper-clad laminates, which are then drilled, plated, and etched to create circuitry. The choice of substrate affects board strength, flexibility, signal integrity, and environmental performance.

Common substrates include rigid FR-4 (glass-epoxy), FR-2 (phenolic paper), and ceramic laminates; flexible options such as polyimide and LCP (liquid crystal polymer); and low-loss materials used for RF, such as PTFE-based laminates and Rogers RT/duroid, as well as alumina ceramics. Each family balances dielectric properties, thermal performance, moisture resistance, and cost.

Key properties are dielectric constant (Dk), loss tangent, thermal conductivity, glass transition temperature (Tg), and coefficient of thermal expansion (CTE). FR-4 typically offers Dk around 4.2–4.8, moderate Tg, and good cost; PTFE-based laminates have Dk near 2–3 with very low loss but higher processing demands; polyimide provides flexibility and higher Tg; ceramic substrates offer excellent thermal stability but higher Dk and potential brittleness.

Manufacturing considerations include prepregs, copper weight, board thickness, and moisture sensitivity. Flexible substrates require careful handling to avoid mechanical stress and delamination. Environmental requirements such as RoHS and halogen-free formulations are common.

Substrates are used across consumer electronics, automotive, aerospace, and communications. High-frequency boards rely on specialized low-loss materials; trends include HDI designs, rigid-flex assemblies, embedded passives, and materials with improved thermal and dielectric performance.