Hollow Fibres in PCB, MCM‐L and PBGA Laminates May Induce Reliability Degradation

The presence of hollow fibres in laminates used in printed circuit boards, multichip module laminated substrates, and plastic ball grid arrays has a potentially significant impact on reliability. Hollow fibres are vacuous glass filaments in E‐glass laminate reinforcements and are seen as a reliability problem since they can provide paths for failure mechanisms such as conductive filament formation. This paper discusses the manufacture of woven fabric laminates and the cause of hollow fibres. Experiments conducted to assess the occurrence of hollow fibres in laminates are then presented along with the key reliability issues.