CoWoS-R is a member of CoWoS advanced packaging family leveraging InFO technology to utilize RDL interposer and to serve the interconnect between chiplets, especially in HBM(high bandwidth memory) and SoC heterogeneous integration. RDL interposer is comprised of polymer and copper traces, and it is relatively mechanically flexible. Such flexibility enhances the C4 joint integrity, and allows the new package can scale up its size to meet more complex functional demands.
The key features of CoWoS-R technology include:
The RDL interposer consists of up to 6L Cu layers for routing with min. of 4um pitch(2um line width/spacing).
The RDL interconnect offers good signal and power integrity performance with lower RC value of the routing line to achieve a high transmission data rate. The coplanar GSGSG and interlayer ground shielding with six RDL interconnections offer superior electrical performance.
RDL layer and C4/UF layers provide good buffer effect due to the CTE mismatch between SoC and the corresponding substrate. The strain energy density is greatly reduced in C4 bump.