Technology Overview

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:

  1. TCI uses existing metal layers and Digital CMOS circuitry, so no special manufacturing process is required.
  2. The area impact of Rx/Tx circuitry is relatively small by using standard CMOS.
  3. TCI is electrically connected, there is no mechanical reliability issues as in TSV.
  4. TCI allows chips from different processes across vendors to stack easily.
  5. 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.
  6. Significant cost savings compared to TSV
  7. Testability is simplified compared to TSV due to enablement of non-contact wafer testing.