Process Development of FlexTrate(TM) Connector for Silicon Interconnect Fabric

Heterogeneous integration is emerging as the mainstay in the performance and scaling enhancement trend. At the Center for Heterogeneous Integration and Performance Scaling (CHIPS), University of California, Los Angeles (UCLA), Silicon Interconnect Fabric (Si-IF) has been established as a heterogeneous wafer-scale integration technology, where bare dies can be mounted on silicon wafer directly with the advantages like fine pitch, small inter-die spacing, lower latency, and higher data bandwidth. As an external communication system for Si-IF, FR4-based periphery connector was investigated earlier but it still has issues such as, CTE mismatch and poor flexibility. To address this problem, Flextrate(TM) Connector, a novel flexible device, is proposed. FlexTrate(TM) is a flexible hybrid packaging platform using fan-out wafer-level packaging method to heterogeneously integrate dies in polydimethylsiloxane (PDMS) substrate. In this thesis, FlexTrate(TM) technology is used to fabricate copper wires on PDMS substrate to form a connector that can serve as an external communication system for Si-IF with better mechanical properties, such as better elongation and lower Young’s modulus

Efficiency and Returns to Scale Measurements with Shared Inputs in Multi-Activity Data Envelopment Analysis: An Application to Farmers' Organizations in Taiwan

This paper addresses the question how team production promotes efficiency of a firm when some inputs can be rewarded on the basis of outputs but some cannot because they are shared among outputs and non-separable. A multi-activity DEA model with variable returns to scale is proposed to provide information on the efficiency performance for organizations with inputs shared among several closely related activities. The model is applied to study the case of 279 farmers' associations in Taiwan. The result suggests that it is important to improve the efficiency of the non-profit oriented activities to improve their overall performances. Three out of four departments of TFAs can gain from economies of scale through expansion, while the remaining one gains through contraction. Thus, policies promoting structural adjustment and consolidations of TFAs would not be inconsistent with public interests.multi-activity DEA, shared inputs, efficiency measure, directional distance function, Productivity Analysis,

Productivity Change in Taiwan's Farmers' Credit Unions: A Nonparametric Risk-Adjusted Malmquist Approach

This article proposes an extended three-stage DEA methodology similar to Fried et al. (2002) to improve the measurement of productivity growth then the assumption of free disposability of undesirable outpu t does not apply. A directional distance function is used to construct adjusted Malmquist-Luenberger productivity indexes which simultaneously account for the impacts of undesirable outputs, environmental variables, and statistical noise. Panel data for 264 farmers' credit unions (FCUs) in Taiwan covering the 1998-2000 period are employed to illustrate the advantages of this method. On average, the productivity of Taiwan's FCUs is found to have deteriorated over the 1998-2000 period. Although an improvement in efficiency has been observed, the major reason for the deterioration is found to be due to the regression of techno logy.Malmquist-Luenberger productivity index, three-stage DEA, undesirable outputs, directional distance function, Agricultural Finance, Productivity Analysis,

Mechanism of thermal field and electric field in resistive random access memory using the high/low-k side wall structure

In the Internet of things (IoT) era, low power consumption memory will be a critical issue for further device development. Among many kinds of next-generation memories, resistive random access memory (RRAM) is considered as having the most potential due to its high performance. To prevent unrecoverable hard break-down of a RRAM device, the RRAM should be collocated with a transistor for external current compliance. With decreasing device cell size, however, the operating voltage of the transistor will become smaller and smaller. Previous study has determined that the forming voltage of RRAM increases when device cell size is reduced, which is a very crucial issue especially when the device is scaled down. We have proposed a high-k sidewall spacer structure in RRAM to solve the dilemma of increasing forming voltages for device cell scaling down. Based on the COMSOL-simulated electrical field distributions in the high-k RRAM. In addition, thermal conductivity of sidewall spacer influenced resistive switching behavior. Suitable thermal conductivity of sidewall materials can enhance resistive switching behavior. Please click Additional Files below to see the full abstract

Entanglement spectrum and entropy in topological non-Hermitian systems and non-unitary conformal field theories

We propose a method of computing and studying entanglement quantities in non-Hermitian systems by use of a biorthogonal basis. We find that the entanglement spectrum characterizes the topological properties in terms of the existence of mid-gap states in the non-Hermitian Su-Schrieffer-Heeger (SSH) model with parity and time-reversal symmetry (PT symmetry) and the non-Hermitian Chern insulators. In addition, we find that at a critical point in the PT symmetric SSH model, the entanglement entropy has a logarithmic scaling with corresponding central charge $c=-2$. This critical point then is a free-fermion lattice realization of the non-unitary conformal field theory.Comment: 17 pages, 11 figure