High TG FR4: Thermal Reliability Beyond Tg

High-Tg FR-4 identifies a thermal-performance class of laminate products, not a single formulation. Material reference.

Thermal Reliability Beyond Tg

For a multilayer board, compare the resin system and complete assembly exposure rather than choosing only the highest Tg. Test method matters: different Tg methods can produce different reported values. Via reliability also needs the actual stackup and manufacturing sequence represented.

Manufacturing and acceptance checks

Specify the exact laminate, Tg method, layer construction and reflow profile. Ask the fabricator to review sequential lamination and plated-via requirements. Define thermal cycling or other acceptance tests where needed, and approve a material substitute against the complete stackup rather than a matching marketing category.

Compare related options

• FR4
• HDI Materials

Reference and scope

Isola: FR408HR construction and thermal test information provides material or specification background. The checks above are purchasing guidance; final acceptance values must come from the agreed grade, product specification and condition.

Send a drawing and material requirements for review. Include quantity, critical dimensions and the inspection evidence required with delivery.