A 3D-Stacked Cortex-M0 SoC with 20.3Gbps/mm² 7.1mW/mm² Simultaneous Wireless Inter-Tier Data and Power Transfer

Abstract

This paper presents a 2-tier 3D-stacked Cortex-M0 SoC, in 65nm CMOS technology, with wireless inter-tier power and data transfer through an inductively coupled bus. The proposed design is the first implementation of a wireless link as part of a standard SoC bus, and achieves 20.3Gbps/mm 2 data, and 7.1mW/mm 2 power transfer simultaneously through a 250 µm channel. This also makes it the smallest ever reported inductive data and power link.

Proximity Wireless Communication Technologies: An Overview and Design Guidelines

“…To overcome these challenges, PWC is being investigated as a wireless 3D integration technology [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32] as described in Sec. I.…”

“…Contrast to the capacitive coupling, since the magnetic field is not be attenuated by the silicon substrate, multiple-chip stacking is possible with the inductive coupling. As a result, inductive coupling has been widely investigated as an PWC technology for 3D integration [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32].…”

“…To achieve such an HDSV power supply, only about 0.1% of the SRAM chip area needs to be allocated for HDSV in the 40-nm example, which is a sufficiently low cost. Wireless power delivery method is also studied as [13], [14], [16]. The use of such advanced implementation technologies in conjunction with inductive coupling communication is expected to enable a 3D interface that has high power efficiency, high bandwidth, and high area efficiency.…”

“…When the circuit board material as well as the material between the coupled circuit boards have the same dielectric constant, the inductive coupling coefficient K L and capacitive coupling coefficient K C become the same (K L = K C = K ). Furthermore, if υ p is the speed of light in the circuit board material, then the TLC transfer characteristic S 21 , computed using equation (13), will reach its maximum value of K when f = υ p /4L. Therefore, the transfer function of TLC is determined by the coupling coefficient K and line length L.…”

“…Furthermore, the couplers can be formed in existing metal layers without requiring special processing steps, resulting in low manufacturing cost and high reliability. While a lot of initial research was focused on capacitive coupling communication technology for 2.5 and 3D integration [2], [3], inductive coupling technology was later developed to overcome challenges faced by capacitive coupling and to enable more chips to be integrated with higher stacking density [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32].…”