Development of compatible wet-clean stripper for integration of CoWP metal cap in Cu/low-k interconnects

Implementation of CoWP metal caps into Cu/low-k integration schemes requires a wet stripper that not only gives efficient cleaning but also has good compatibility to CoWP and low-k dielectrics. This paper describes a novel non-fluoride CoWP compatible stripper, developed based on a systematic study of the effect of stripper components, i.e. solvent, corrosion inhibitor, and stripper pH. Electrochemical methods were used to characterize galvanic corrosion of the CoWP/Cu couple and to estimate CoWP etch rate. Our studies showed that a traditional fluoride stripper caused severe damage to CoWP capping layer. The new stripper achieved a good balance between cleaning efficiency and compatibility to CoWP and low-k dielectrics, and demonstrated significant advantages in electrical properties over the traditional fluoride stripper.     

Semiconductor Yield Analysis and Multi-Chip Package(MCP) Dic Pairing Optimization using Machine Learning

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Effects of ultra‐high flux and intensity distribution in multi‐junction solar cells

We report results of high‐flux experiments on tandem solar cells, with a real‐sun probe predicated on mini‐dish fiber‐optic concentrators. Experimental results and their interpretation focus on: (a) a striking insensitivity of cell efficiency to flux map; (b) the predictability of the flux values at which cell efficiency peaks; and (c) performance of the same cell architecture at markedly smaller cell area. Copyright © 2006 John Wiley & Sons, Ltd.     

Engineering the Interlayer Spacing by Pre-Intercalation for High Performance Supercapacitor MXene Electrodes in Room Temperature Ionic Liquid

MXenes exhibit excellent capacitance at high scan rates in sulfuric acid aqueous electrolytes, but the narrow potential window of aqueous electrolytes limits the energy density. Organic electrolytes and room-temperature ionic liquids (RTILs) can provide higher potential windows, leading to higher energy density. The large cation size of RTIL hinders its intercalation in-between the layers of MXene limiting the specific capacitance in comparison to aqueous electrolytes. In this work, different chain lengths alkylammonium (AA) cations are intercalated into Ti₃C₂T_x, producing variation of MXene interlayer spacings (d-spacing). AA-cation-intercalated Ti₃C₂T_x (AA-Ti₃C₂), exhibits higher specific capacitances, and cycling stabilities than pristine Ti₃C₂T_x in 1 m 1-ethly-3-methylimidazolium bis-(trifluoromethylsulfonyl)-imide (EMIMTFSI) in acetonitrile and neat EMIMTFSI RTIL electrolytes. Pre-intercalated MXene with an interlayer spacing of ≈2.2 nm, can deliver a large specific capacitance of 257 F g⁻¹ (1428 mF cm⁻² and 492 F cm⁻³) in neat EMIMTFSI electrolyte leading to high energy density. Quasi elastic neutron scattering and electrochemical impedance spectroscopy are used to study the dynamics of confined RTIL in pre-intercalated MXene. Molecular dynamics simulations suggest significant differences in the structures of RTIL ions and AA cations inside the Ti₃C₂T_x interlayer, providing insights into the differences in the observed electrochemical behavior.     

组合了电源控制、用户输入功能的单刀单掷按钮开关

本设计实例介绍了对某种旧设计的增强措施(参考资料1)。图1中的电路使用常开型单刀单掷按钮开关S1,它代替了原始设计要求的单刀双掷开关。您可以使用膜片开关来大大简化该器件的工业设计并增强它的人机控制特性。另外,该电路消除了流过未动作开关的电流,由此略微减少了工作模式中的泄漏电流。     

Motion-sensor fusion-based gesture recognition and its VLSI architecture design for mobile devices

With the rapid proliferation of smartphones and tablets, various embedded sensors are incorporated into these platforms to enable multimodal human–computer interfaces. Gesture recognition, as an intuitive interaction approach, has been extensively explored in the mobile computing community. However, most gesture recognition implementations by now are all user-dependent and only rely on accelerometer. In order to achieve competitive accuracy, users are required to hold the devices in predefined manner during the operation. In this paper, a high-accuracy human gesture recognition system is proposed based on multiple motion sensor fusion. Furthermore, to reduce the energy overhead resulted from frequent sensor sampling and data processing, a high energy-efficient VLSI architecture implemented on a Xilinx Virtex-5 FPGA board is also proposed. Compared with the pure software implementation, approximately 45 times speed-up is achieved while operating at 20 MHz. The experiments show that the average accuracy for 10 gestures achieves 93.98% for user-independent case and 96.14% for user-dependent case when subjects hold the device randomly during completing the specified gestures. Although a few percent lower than the conventional best result, it still provides competitive accuracy acceptable for practical usage. Most importantly, the proposed system allows users to hold the device randomly during operating the predefined gestures, which substantially enhances the user experience.     

Ferroelectric Materials: Probing Local and Global Ferroelectric Phase Stability and Polarization Switching in Ordered Macroporous PZT (Adv. Funct. Mater. 5/2011)

We describe the characterization, ferroelectric phase stability and polarization switching in strain‐free assemblies of PbZr_0.3Ti_0.7O₃ (PZT) nanostructures. The 3‐dimensionally ordered macroporous structures present uniquely large areas and volumes of PZT where the microstructure is spatially modulated and the composition is homogeneous. Variable temperature powder X‐ray diffraction (XRD) studies show that the global structure is crystalline and tetragonal at room temperature and undergoes a reversible tetragonal to cubic phase transition on heating/cooling. The measured phase‐transition temperature is 50–60 °C lower than bulk PZT of the same composition. The local ferroelectric properties were assessed using piezoresponse force spectroscopy that reveal an enhanced piezoresponse from the nanostructured films and demonstrate that the switching polarization can be spatially mapped across these structures. An enhanced piezoresponse is observed in the nanostructured films which we attribute to the formation of strain free films, thus for the first time we are able to assess the effects of crystallite‐size independently of internal stress. Corresponding polarization distributions have been calculated for the bulk and nanostructured materials using a direct variational method and Landau‐Ginzburg‐Devonshire (LGD) theory. By correlating local and global characterization techniques we have for the first time unambiguously demonstrated the formation of tetragonal and ferroelectric PZT in large volume nanostructured architectures. With the wide range of materials available that can be formed into such controlled architectures we conclude that this study opens a pathway for the effective studies of nanoscale ferroelectrics in uniquely large volumes.     

A review of silicon-based wafer bonding processes,an approach to realize the monolithic integration of Si-CMOS and Ⅲ-Ⅴ-on-Si wafers

The heterogeneous integration of Ⅲ-Ⅴ devices with Si-CMOS on a common Si platform has shown great promise in the new generations of electrical and optical systems for novel applications,such as HEMT or LED with integrated control cir-cuitry.For heterogeneous integration,direct wafer bonding(DWB)techniques can overcome the materials and thermal mis-match issues by directly bonding dissimilar materials systems and device structures together.In addition,DWB can perform at wafer-level,which eases the requirements for integration alignment and increases the scalability for volume production.In this paper,a brief review of the different bonding technologies is discussed.After that,three main DWB techniques of single-,double-and multi-bonding are presented with the demonstrations of various heterogeneous integration applications.Mean-while,the integration challenges,such as micro-defects,surface roughness and bonding yield are discussed in detail.     

Unfreezable Water in Apple Treated by Pulsed Electric Fields: Impact of Osmotic Impregnation in Glycerol Solutions

The effects of pulsed electric fields (PEF) and osmotic impregnation in glycerol solution on the amount of unfreezable water in apple were determined by means of low-temperature differential scanning calorimetry (DSC). The obtained data were compared with behaviour of pure water–glycerol solutions (sample WG). PEF treatment was applied using a near-rectangular monopolar generator with pulse duration of 100 μs at electric field strength of 800 V/cm. The osmotic impregnation of PEF-treated apple discs was done using water–glycerol (sample AWG) and apple juice–glycerol (sample AJG) osmotic solutions at different concentration of water or juice in glycerol, W = 30–100 wt%. The data evidenced that for the PEF-treated samples the glycerol was able to penetrate successfully inside apple tissue. The state diagrams for WG, AWG and AJG samples were rather similar. It was observed that free water existed only for moisture content above some minimum value. The unfreezable water content was the largest in AJG, followed by WG and AWG. The juice concentration in glycerol W ≈ 80 wt% was found to be optimal for preservation of the texture of PEF-treated samples.