ThruChip Interface (TCI) uses Inductive Coupling technology to enable Near Field Wireless Communication between 3D stacked chips.
It uses the existing metal layers in a regular process as inductive coils. Digital logic interconnections between stacked chips go through the coils.
The placement of TCI is very flexible due to the nature of its design properties; we have implemented it above SRAM structures and TCI does not interfere with the memory cell.
Key advantages of TCI technology are:
- TCI uses existing metal layers and Digital CMOS circuitry, so no special manufacturing process is required.
- The area impact of Rx/Tx circuitry is relatively small by using standard CMOS.
- TCI is electrically connected, there is no mechanical reliability issues as in TSV.
- TCI allows chips from different processes across vendors to stack easily.
- TCI can achieve high speed, low power, and high integration
- Over 10Gb/s with one pair of coils
- Less than 0.1 pJ/b in leading edge technologies
- Can stack large number of die, eg see example of 128 NAND FLASH memories stacked.
- Significant cost savings compared to TSV
- Testability is simplified compared to TSV due to enablement of non-contact wafer testing.