This paper repots on a novel pick-up and place process for FO-WLP using high expansion tape and tape expansion machine device. We previously reported that we have developed the novel tape expansion machine with a new function allowing that tapes can be expanded in four directions to individually control these expansions. However, the tapes which are generally used as conventional dicing tape have problems such as tape breaking during high expansion and uneven chip distances after expansion. In this study, the effect of stress-strain curve of adhesive for expansion tape is investigated in order to achieve both properties of chip distances and chip accuracies after expanding. As a result of evaluation, average chip distance increases to 2,930μm (initial chip distance; 35^m) with 3mm square Si chips and the standard deviation is 43μm

Study of Optimizing Stress-Strain Curve of Adhesive for 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. 

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.

This paper describes advanced assembly technologies based on a new tape expansion technique with a selective UV irradiation method for the application of FOWLP (Fan-Out Wafer-Level Packaging) with millimeter-scale dies and micro-LED display with several tens of micrometer-scaled dielets. The assembly technologies allow us to uniformly expand expansion tapes in all direction and array the dies/dielets at the regular pitches desired for their products. We demonstrate the uniform expansion of an expansion tape with 3-mm-square Si dies and 50-μm-square Si dielets using selectively irradiated UV light through a photomask.

T. Fushimi

Papers

Advanced Tape Expansion/Assembly Technology for FOWLP and Micro-LED Display