Logic / Memory

A variety of memory and logic devices, including DRAM (dynamic random access memory), SDRAM (synchronous dynamic random access memory), Flash memory (NAND or NOR), CPU (central processing unit), GPU (graphics processing unit), etc., are widely used in computers, digital music players, gaming devices and mobile internet devices. For instance, since SDRAM was introduced to computers, further generations of SDRAM (DDR1, DDR2 and DDR3) have entered the mass market, with DDR4 currently being designed and anticipated to become available in the coming years.

Through-silicon via (TSV) is a structure providing an electrical pathway through the thickness of a silicon die. TSV technology represents a system-level integration of planar devices that are stacked and interconnected in the z-direction. The key enabling technologies for TSV integration include TSV formation for electrically isolated interconnects through wafers, wafer thinning for the final thickness of less than 50µm and aligned wafer bonding - particularly, chip-to-wafer and wafer-to-wafer bonding - with a thin-wafer handling mechanism.

Major benefits of 3D ICs include their smaller footprint, higher speed and bandwidth and lower power consumption with reduced heat generation. Last but not least, 3D IC technology enables heterogeneous integration in which the individual circuit layers can be built on different types of wafers and manufactured using different processes.

The markets for 3D integration can be classified into three major groups: 3D WLP encapsulation applications for CMOS image sensor (CIS) modules and high-end MEMS devices; 3D TSV interposer modules for stacking heterogeneous devices; and 3D TSV stacks for homogenous memory stacking as well as heterogeneous stacking with memory and logic devices. 3D TSV stacks are expected to have the steepest growth rate over the next few years.