Features

Molded underfill (MUF) is increasingly being used to lower costs and increase throughput in flip chip assembly. Compared to older underfill processes, MUF decreases material costs, allows for batch processing of both flip chip underfill and overmolding in strip format, and enables smaller package size for today’s powerful mobile devices

The main challenge with MUF inspection for flip chips is that the acoustic signal and its reflections need to penetrate the overmold layer, which is not as transparent to ultrasound as bare silicon. Also, the uneven particle size within the MUF epoxy base causes uneven scattering and absorption of the signal, which can obscure small features such as Cu pillars. Sonix MFCI™ software for molded flip chip imaging addresses these challenges to improve spatial resolution, edge resolution and contrast in advanced MUF inspection applications.