Negative Expansion Materials Resist Warpage

Growing sizes of packages, interposers and panels increase warpage due to differences in thermal expansion coefficients of materials. Commercial negative thermal expansion (NTE) materials are beginning to be used in chip packaging to compensate for expansion, but their mass adoption depends on temperature range, compatibility and mixture purity.

• Warpage limits growth of package, interposer and panel sizes
• NTE materials contract when heated and compensate expansion of adjacent layers
• Added to epoxy compounds and underfill to reduce CTE
• Mass adoption depends on temperature range and mixture purity