Major efforts are currently underway throughout the IC industry to develop the capability to integrate device chips by stacking them vertically and using through-silicon vias (TSVs). The resulting interconnect density, bandwidth, and compactness achievable by TSV technology exceed what is currently possible by other packaging approaches. Market-driven applications of TSV involving memory include multi-chip high-performance DRAM, integration of memory and logic functions for enhanced video on handheld devices, and stacked NAND flash for solidstate drives. High-volume commercial implementation of 3D TSV is imminent but faced by special challenges of design, fabrication, bonding, test, reliability, know-good die, standards, logistics, and overall cost. The main focus of this paper is the unit-process and process-integration technology required for TSV fabrication at the wafer level: deep silicon etching, dielectric via isolation, metallization, metal fill, and chemicalmechanical polishing.

This work studied the removal mechanism of a tungsten chemical mechanical planarization (CMP) process on a dual head polishing platform. The two key parameters studied were slurry abrasive concentration and process temperature. The removal rate was observed to scale with the cubic root of the abrasive concentration. The polishing temperature showed a linear relation with the removal rate in the temperature controlled experiment. A potential mechanism was explored for the removal of the tungsten film to explain the experimental results.

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Because the gate height is critical to transistor performance, controlling gate height precisely and uniformly is the primary challenge for the replacement metal gate aluminum CMP process. A real-time profile control (RTPC) method was combined with a laser-based endpoint system to achieve within-wafer and wafer-to-wafer gate height uniformity requirements. To meet another challenge in Al CMP, defect performance was improved by 20X via consumables selection and process optimization.

Turbochargers (TCs) aid to produce smaller and more fuel-efficient passenger vehicle engines with power outputs comparable to those of large displacement engines. This paper presents further progress on the nonlinear dynamic behavior modeling of rotor-radial bearing system (RBS) by including engine-induced (TC casing) excitations. The application concerns to a semi-floating bearing design commonly used in high speed turbochargers. Predictions from the model are validated against test data collected in an engine-mounted TC unit operating to a top speed of 160 krpm (engine speed = 3600 rpm). The bearing model includes non-cylindrical lubricant films as in a semi-floating ring bearing with an anti-rotation button. The nonlinear rotor transient response model presently includes input base motions for the measured TC casing accelerations for increasing engine load conditions. Engines induce TC casing accelerations rich in multiple harmonic frequencies; amplitudes being significant at 2 and 4 times the main engine speed. FFT post-processing of predicted nonlinear TC shaft motions reveals a subsynchronous whirl frequency content in good agreement with test data, in particular for operation at the highest engine speeds. Predicted total shaft motion is also in good agreement with test data for all engine loads and over the operating TC shaft speed range. The comparisons validate the rotor-bearing model and will aid in reducing product development time and expenditures.