Samsung develops new chip-stacking solution
The R&D folks at Samsung have come up with what they claim is the industry's first process that allows 16 memory chips to be stacked on a single package. To achieve this feat, Samsung used some new wafer thinning and chip sawing techniques:
For the new 16-chip process, Samsung introduced wafer-thinning technology that eliminates 24 over 25 (24/25) of the thickness of each fabricated wafer to reduce the overall thickness to only 30-microns (μm). This is just 65 percent the thickness of the 10-chip MCP wafer (45μm) Samsung developed in 2005 and similar to the size a human cell, which measures 20 to 30 microns.
As part of its MCP breakthrough, Samsung also developed a new laser-cutting technology to cut the wafer into individual chips. This new cutting process prevents the memory chips from breaking into pieces when they are cut using conventional blade sawing technology, which was originally designed only for sawing wafers up to 80 microns thick.
The resulting chips are stacked in a zig-zag pattern bonded by 20μm-thick adhesive, resulting in a 16-die stack that measures only 1.4mm in height. Using 8Gb NAND flash chips, the new stacking process allows up to 16GB to be stored on a single multi-chip package—the highest density ever developed, according to Samsung.