Spin qubit systems are promising candidates for Si-based quantum computing. The conventional spin-qubit cell consists of control and readout units around a quantum dot (QD) with the excess electrons functioning as spin qubits. This complicates the integration of qubits because of the many wires and extra mechanisms, such as the requirement of shuttling parts. Therefore, we propose a new structure of stacked qubits, in which the gate-all-around (GAA) channel plays the role of both control and readout, and integration of qubits is feasible by extending the commercial silicon technologies. The qubit-QDs are placed in the gate insulator between the channel region and gate electrodes, similar to floating gates. Here, we present technology computer-aided design (TCAD) simulations to show how the extra electric charges in the QD affect the channel current.
This study experimentally investigates the performance of a novel jet impingement cooler for high performance interposer package. The cooler first cools the HBM chips and then the logic chip using the same fluid stream. With water as the working fluid, the cooling solution was able to upgrade the thermal design power (TDP) of the package beyond 1 kW to a maximum of 1.86 kW at 4 L/min. The thermohydraulic performance of the cooler was then investigated in terms of the thermal resistance of all chips and the overall cooler pressure drop. The minimum thermal resistance for the logic chip was similar to 0.2 K.cm(2)/W which was obtained at 4 L/min with a modest pressure drop of 48.32 kPa. Excellent surface temperature uniformity was observed even at TDP of 1.86 kW (252 W/cm(2)) with the temperature variation being within 3 degrees C. Finally, the temperature rise across different chips was also investigated and it was revealed that the cooling scheme can be readily adapted for packages with more than 4 HBMs per logic chip and multiple such packages can be cooled using the same fluid stream for the given temperature constraints for logic chip and HBMs.
A high-speed, manufacturable, fully chiplet integration process using Face-Down bonding to 300 mm waffle-wafer and bumpless Chip-on-Wafer (COW) has been developed for the first time. The inkjet method successfully formed a thin adhesive layer on the bottom of the waffle wafer, with no voids even at a 5 mu m adhesive thickness. Over 30,000 chips with a narrow gap of 40 mu m were bonded with a misalignment of less than 10 mu m and a short bonding time of a few milliseconds per chip.
Ultra-high-density IPD capacitor is increasingly essential for high performance computing (HPC), artificial intelligence (AI) systems and mobile application compact systems in 3DFabric platform. Utilizing advanced etching and deposition techniques, Deep Trench Capacitor (DTC) features deep and narrow trenches filled with high-K dielectrics and conductive electrodes. DTC can provide significantly increased capacitance density with low equivalent series resistance (ESR) and equivalent series inductance (ESL). The miniaturization of capacitors will continue to advance Moore's law for SOC.
We address a trade-off issue between chip assembly time and positioning accuracy in a traditional pick-and-place method using self-assembly technology driven by liquid surface tension. This method allows 16-layer stacking of 50-mu m-thin chips fabricated via Plasma Dicing Before Grinding (PDBG). The surface tension of liquid droplets enables sub-50 nm alignment accuracy even with manual chip placement. By identifying key parameters such as pre-alignment position and liquid volume/distribution, we optimize the self-assembly process for High Bandwidth Memory (HBM) applications. Additionally, we discuss the effects of liquid bridges and wetting contrast between the chip surface and sidewall on multi-layer stacking.
