Advanced Assembly Technology for Small Chip Size of Fan-out WLP using High Expansion Tape

This paper reports on the advanced assembly technology for small chip size of Fan-out WLP(FO-WLP) using high expansion tape. In a preceding paper, we reported that we have developed new tape expansion machine which can expand tape in four directions individually. Using this expansion machine device, we have developed high expansion tape which can get enough chip distance after expansion. Our expansion technology provides both high throughput and high placement accuracy. These previous studies have been evaluated using 3 mm x 3 mm chips assuming an actual FO-WLP device. Since our process can be handled by wafer size, smaller chip size improves throughput than larger chip size. In this study, we evaluate with 0.6 mm x 0.3 mm chip size and investigate tape characteristics required for small chip size expansion. By optimizing adhesive thickness and composition of adhesive, we succeed in developing high expansion tape for small chip size with good expandability and no adhesive residue on the expanded chip. We indicate that our proposal process is also effective for small chip size of FO-WLP.