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I. AbstractA high performance 45nm BEOL technology with proven reliability is presented. This BEOL has a hierarchical architecture with up to 10 wiring levels with 5 in PECVD SiCOH (k=3.0), and 3 in a newly-developed advanced PECVD ultralow-k (ULK) porous SiCOH (k=2.4). Led by extensive circuit performance estimates, the detrimental impact of scaling on BEOL parasitics was overcome by strategic introduction of ULK at 2x wiring levels, and increased 1x wire aspect ratios in lowk, both done without compromising reliability. This design point maximizes system performance without adding significant risk, cost or complexity. The new ULK SiCOH film offers superior integration performance and mechanical properties at the expected k-value. The dual damascene scheme (non-poisoning, homogeneous ILD, no trench etch-stop or CMP polish-stop layers) was extended from prior generations for all wiring levels. Reliability of the 45 nm-scaled Cu wiring in both low-k and ULK levels are proven to meet the criteria of prior generations. Fundamental solutions are implemented which enable successful ULK Chip-Package Interaction (CPI) reliability, including in the most aggressive organic flipchip FCPBGA packages. This represents the first successful implementation of Cu/ULK BEOL to meet technology reliability qualification criteria. II. BEOL IntegrationAggressive 0.7x scaling from 65nm BEOL wiring and contact dimensions has been achieved using hyper-NA (1.2NA) lithography. This enables a 2x active area reduction for migratable designs. The 45 nm BEOL hierarchy is shown in Fig. 1. At the 1x wiring levels (M1-M3), BEOL delays are largely impacted by resistance increases from scaling. Increased aspect ratio in conjunction with an optimized Cu barrier-seed process results in up to 25% resistance and 20% RC reductions, respectively, per Fig. 2. Typically, increasing Cu aspect ratios degrades stress migration (SM) and electromigration (EM) reliability. However, Figs. 3-4 show than an optimized Cu barrier-seed process and tooling enables zero SM fails and good EM performance. Thus scaling impacts to BEOL parasitics at 45 nm 1x levels are mitigated, while extending the low-k SiCOH film and integration scheme [1] from 90 and 65 nm technologies [2]. The industry-wide effort to integrate ULK BEOL dielectrics has focused primarily on the 1x wiring levels [3][4][5]. In contrast, our strategy is to introduce ULK at the 2x levels (M4-M6), which are typically dominated by relatively longer RC-dominated runs. The 15% RC benefit for ULK (k=2.4) over low-k (k=3.0) at these levels, as shown in Fig. 5, is leveraged to deliver superior BEOL performance at reduced risk. These 2x levels consist of dual damascene Cu in homogeneous PECVD ULK porous-SiCOH which is based on advanced precursors and UV-cure tooling [6][7]

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Abstract-Dielectric Elastomer (DE) transducers have emerged as a very interesting alternative to the traditional electrodynamic transducer. Lightweight, small size and high maneuverability are some of the key features of the DE transducer. An amplifier for the DE transducer suitable for audio applications is proposed and analyzed. The amplifier addresses the issue of a high impedance load, ensuring a linear response over the midrange region of the audio bandwidth (100 Hz -3.5 kHz). THD+N below 0.1% are reported for the ± 300 V prototype amplifier producing a maximum of 125 Var at a peak efficiency of 95 %. [7]. While these audio systems are dominating the market of sound reproduction, they suffer from the poor efficiency imposed by the electrodynamic transducer, and the weight of the electromagnet. As a consequence the audio community is constantly searching for new audio transducers. An alternative to the electrodynamic transducer is the electrostatic transducer. Electrostatic transducers are known from their usage in electrostatic loudspeakers, however Dielectric Elastomers (DE) can also be used to form an electrostatic transducer [8], [9], [10]. Such capacitive transducers present a high impedance, frequency depended nonlinear load to the amplifier. A DE transducer is shown in figure 1. The DE transducer is constructed by printing compliant electrodes on a thin piece of silicone. Commercial electrostatic loudspeakers are driven from tube, linear or audio-transformer based amplifier solutions. Consequently these systems suffer from being bulky, fragile and inefficient. In order to establish the full potential of the DE transducer, a new generation of audio amplifiers must be developed. These amplifiers should have a high power density, low power loss and be robust. Accordingly it is proposed to use a switch-mode audio amplifier or class D amplifier for driving the DE transducer INTRODUCTION