Microarchitectures for Managing Chip Revenues under Process Variations

As transistor feature sizes continue to shrink into the sub-90 nm range and beyond, the effects of process variations on critical path delay and chip yields have amplified. A common concept to remedy the effects of variation is speed-binning, by which chips from a single batch are rated by a discrete range of frequencies and sold at different prices. In this paper, we discuss strategies to modify the number of chips in different bins and hence enhance the profits obtained from them. Particularly, we propose a scheme that introduces a small Substitute Cache associated with each cache way to replicate the data elements that will be stored in the high latency lines. Assuming a fixed pricing model, this method increases the revenue by as much as 13.8% without any impact on the performance of the chips.     

基于结构级的低功耗设计方法

随着移动设备需求量的不断增大和芯片工作速度的不断提高，芯片的功耗已经成为电路设计者必须考虑的问题，对于芯片整体性能的评估已经由原来的面积和速度的权衡变成面积、时序、可测性和功耗的综合考虑，并且功耗所占的权重会越来越大．文中主要讲述通过不同方法在进行结构设计时如何实现低功耗设计，比如采用并行结、流水结构、优化编码风格等等。     

双脉冲电导率测量仪设计及实现

介绍了一种双脉冲电导率测量仪,采用双脉冲激励法测量溶液中的电导率,使用双极性方波脉冲电压源作为系统激励源,减小极化效应和电容效应的影响.采用MAX313实现量程的自动转换.用铂热电阻对温度进行测量,软件校正温度传感器的非线性,并对电导率进行温度补偿.利用最小二乘法对电导率测量仪进行标定.设计了RS-485总线网络通讯协...     

电路板红外图像多目标提取算法

电路板红外图像芯片提取是电路板红外图像故障检测系统中的重要环节,传统的芯片发热区域提取方法或多或少需要人工干预,在芯片较多和热辐射情况复杂电路板中人工参与效果不是很理想．基于电路板红外图像特征提出了一种自适应多目标区域增长算法,将该多目标区域增长算法与GVF—Snake模型相结合用于电路板红外图像芯片提取．利用多目标区域增长算法将每一块芯片的发热区域和辐射区域一并提取,再利用区域增长确定GVF-Snake模型初始轮廓,利用GVF模型进行芯片发热区域提取．实验表明,这种算法能够无人工干预的准确提取电路板红外图像所有芯片发热区域,具有一定的实用性和鲁棒性．     

微陀螺仪敏感芯片的选择性电铸技术研究

介绍了一种新的MEMS器件敏感芯片的制备技术———选择性电铸技术。以金为检测电极、铜为牺牲层、正胶作为电铸胎膜,在牺牲层上经过数次电铸形成MEMS器件敏感芯片的各组成部分,腐蚀掉牺牲层后便得到了所需的敏感芯片。以微机械陀螺仪敏感芯片的制备为例,介绍了选择性电铸技术的工艺流程,进行了工艺流片,所制备的微机械陀螺仪敏感芯片结构完整、侧壁陡直、表面平整。该技术在电容式微加速度计及微机械陀螺仪等多种MEMS器件敏感芯片的制作中有广泛的应用前景。     

The effect of injection molding PMMA microfluidic chips thickness uniformity on the thermal bonding ratio of chips

Injection molding PMMA microfluidic chips can significantly improve the efficiency of chips forming. However, due to the coexistence of macro and micro effects in the injection molding process, the thickness uniformity of molding substrates is poor, which will seriously affect the thermal bonding quality of chips. In this paper, the effect of injection molding PMMA microfluidic chips thickness uniformity on the thermal bonding ratio and the quality of micro-channels was studied by experiments and simulations. The results show that when the following three conditions were satisfied during injection molding process, chips bonding ratio reaches to 93.9?% and the distortions of micro-channels caused by thermal bonding were acceptable. Firstly, the cover plates flatness error is smaller than 50–60?μm and substrates flatness error is smaller than 80–90?μm. Secondly, the maximum thickness difference of stack chips (cover plate stack with substrate) is smaller than 70–80?μm. Thirdly, chips thickness of the middle is larger than that of the two ends along their length direction and chips thickness distribute evenly along their width direction. These conclusions can be used for the parameters selection and moulds design during injection molding process of PMMA microfluidic chips.     

寄存器传输级低功耗设计方法

随着移动设备需求量的不断增大和芯片工作速度的不断提高，芯片的功耗已经成为电路设计者必须考虑的问题，对于芯片整体性能的评估已经由原来的面积和速度的权衡变成面积、时序、可测性和功耗的综合考虑，并且功耗所占的权重会越来越大。本文主要讲述在RTL设计中如何实现低功耗设计。     

Applications and architectures [microprocessor chips]

Chips are getting more expensive both to design and to manufacture. That makes it tempting for semiconductor companies to push more functions onto a single chip, using software to customize it for specific applications. Using software to customize a few platforms for a variety of applications spreads the mask costs over more chips. It also saves the time of switching from one mask set to another. Time is money, so reducing the variety of parts that require fabrication helps reduce costs in other ways as well. As a result, chip manufacturers try to design platforms that can support a range of products. Customers who buy the chips to build systems use software to customize the functionality.     

Precision moulding of biomimetic disposable chips for droplet-based applications

In this study, we present a biomimetic approach to improve the stability and reproducibility of droplet generation processes and to reduce the adhesion of aqueous droplets to channel surfaces of microfluidic polymer chips. The hierarchical structure of the lotus leaf was used as a template for a partial laser structuring of the moulds that were used for casting the polymer chips. The hydrophobic wax layer of the lotus leaf was technologically replicated by coating the polymer chips using a plasma deposition process. The resulting microfluidic polymer chip surfaces reveal a topography and a surface free energy similar to those of the lotus leaf. Subsequent droplet-based microfluidic experiments were performed using a 2D flow focussing set-up. Droplets from both, serum-supplemented cell culture medium and anticoagulated human whole blood, could be generated stably and reproducibly using a fluorocarbon as continuous phase. The presented results illustrate the application potential of the lotus-leaf-like polymer chips in life sciences, e.g. in the field of personalised medicine.     

Pneumatic dispensing of nano- to picoliter droplets of liquid metal with the StarJet method for rapid prototyping of metal microstructures

This study presents a new, simple and robust, pneumatically actuated method for the generation of liquid metal micro droplets in the nano- to picoliter range. The so-called StarJet dispenser utilizes a star-shaped nozzle geometry that stabilizes liquid plugs in its center by means of capillary forces. Single droplets of the liquid metal can be pneumatically generated by the interaction of the sheathing gas flow in the outer grooves of the nozzle and the liquid metal. For experimental validation, a print head was build consisting of silicon chips with a star-shaped nozzle geometry and a heated actuator (up to 280°C). The silicon chips are fabricated by Deep Reactive Ion Etching (DRIE). Chip designs with different star-shaped geometries were able to generate droplets with diameters in the range of the corresponding nozzle diameters. The StarJet can be operated in two modes: Either continuous droplet dispensing mode or drop on demand (DoD) mode. The continuous droplet generation mode for a nozzle with 183?μm diameter shows tear-off frequencies between 25 and 120?Hz, while droplet diameters remain constant at 210?μm for each pressure level. Metal columns were printed with a thickness of 0.5–1.0?mm and 30?mm height (aspect ratio >30), to demonstrate the directional stability of droplet ejection and its potential as a suitable tool for direct prototyping of the metal microstructures.     

低成本微反应槽PCR芯片阵列双重控制系统

设计了内部不含温度传感元件、加热元件的低成本微反应槽聚合酶链式反应（PCR）芯片．研制了宏观集中控制与微观分散控制有机结合的双重控制系统，该系统具备对PCR芯片的批量处理能力；宏观集中控制装置以水为传热媒质通过特制换热器给芯片提供聚合酶反应所需的基本温度；在柔性印刷电路板上形成与芯片阵列对应的微型加热器阵列，针对各芯片进行分散的温度补偿。     

带有非边界扫描器件的混装电路的扫描链优化配置

在混装电路中,由不同的非边界扫描器件所组成的簇所需要的测试向量的数目可能是不同的,根据不同的簇所需要的测试向量的不同,可以将整个测试过程分为不同的测试阶段,每个测试阶段过后都会有一个或者多个扫描芯片处于bypass状态,而此时其长度只有1,也就是说每一个扫描链的长度是随着测试矢量的移出而变化的,整个扫描链的配置过程中,需要考虑这样两个问题：如何将扫描芯片分配给各条扫描链以及如何排列各条扫描链中扫描芯片的顺序,提出了一种如何配置单链的方法,即优化配置扫描芯片在扫描链中的顺序,这种方法同样可以被应用到多链.     

Two-layer multiplexed peristaltic pumps for high-density integrated microfluidics

The integration and operation of a large number of components is needed to enable ever more complex and integrated chemical and biological processes on a single microfluidic chip. The capabilities of these chips are often limited by the maximum number of pumps and valves that can be controlled on a single chip, a limitation typically set by the number of pneumatic interconnects available from ancillary hardware. Here, we report a multiplexing approach that greatly reduces the number of external pneumatic connections needed for the operation of a large number of peristaltic pumps. The utility of the approach is demonstrated with a complex microfluidic network capable of generating and routing liquid droplets in a two-phase flow. We also report a set of design rules for the design and operation of multiplexed peristaltic pumps, based on a study of the effect of the number of valves per pump and the valve-to-valve distance on the performance of peristaltic pumps. The multiplexing approach reported here may find application in a wide range of microfluidic chips for chemical and biological applications, especially those that require the integration of many different operations on a single chip and those that need to perform similar operations massively in parallel, in sub-nanoliter volumes.     

Free-standing SU-8 microfluidic chips by adhesive bonding and release etching

Free-standing SU-8 chips with enclosed microchannels and high density of fluidic inlets have been made in a three-layer process which involves SU-8 to SU-8 adhesive bonding and sacrificial etching. With this process we can fabricate microchannels with depths ranging from 10 to 500 μm, channel widths from 10 to 2000 μm and lengths up to 6 cm. The process is optimized with respect to SU-8 glass transition temperature. Thermal stresses and thickness non-uniformities of SU-8 are compensated by novel mask design features, the auxiliary moats. With these process innovations filling of microchannels can be prevented, non-bonded area is minimized and bonding yields are 90% for large-area microfluidic chips. We have released up to 100 mm in diameter sized microfluidic chips completely from carrier wafers. These free-standing SU-8 chips are mechanically strong and show consistent wetting and capillary filling with aqueous fluids. Fluidic inlets were made in SU-8 chips by adding one lithography step, eliminating through-wafer etching or drilling. In our process the inlet size and density is limited by lithography only.     

Influence of environmental temperature on the dynamic properties of a die attached MEMS device

Die attach is one of the major processes that may induce unwanted stresses and deformations into micro-electro-mechanical systems (MEMS). The thermo-elastic coupling between the die and package may affect the performance of MEMS under various temperature loads, causing unreasonable effects of the output signal, such as zero offset, temperature coefficient of offset (TCO), nonlinearity, ununiformity and hysteresis, etc. A complete characterization of these effects is critical for a more reliable design. This work presents experimental studies of the temperature effects on the dynamic properties of MEMS. Microbridges and strain gauges with different dimensions were used as test structures. They were surface-micromachined on test chips and the chips were die attached on organic laminate substrates using epoxy bonding as well as tape adhering. The material and dimension of the substrate were specially defined to amplify the magnitude of the coupled deformation for the convenience of investigation. Modal frequencies of the microbridges under a set of controlled environmental temperature before and after die attach were measured using a laser Doppler vibrometer system. The average initial residual strain was also measured from the strain gauges to help analyze the dynamic behavior. Nonlinear TCO of the frequencies were observed to be as large as 2,500–5,000 ppm for the epoxy-bonded samples, in contrast with much smaller values for the tape-adhered and unpackaged ones. The frequencies recovered to their original values beyond the curing temperature of the epoxy. A distributed feature was also observed in frequencies of the microbridges with the same length but at different locations of the chip with a maximum relative difference of 20%. The process of thermal cycling and wire bonding was also applied to the samples and caused tender shifts of the frequencies. The experiments reveal major factors that are related to the temperature effects of die attached MEMS and the results are useful for improving the reliability of a package–device co-design.     

Influence of tool fabrication process on characteristics of hot embossed polymer microfluidic chips for electrospray

Fabrication techniques for mass manufacture of disposable polymer microfluidic chips are important for electrospray application used in mass spectrometry. Hot embossing offers advantages over traditional MEMS fabrication techniques and is the focus of this research. The aim of the paper is to evaluate hot embossed open channel polymer chips using two different hot embossing tools. One tool was fabricated in nickel using the electroforming process, and the other in high carbon bright steel by laser machining technique using a pulsed Nd:YAG laser that is normally used for conventional applications. Process parameters are determined and measurement of dimensions and surface roughness of tools and chips are presented. Depending on the fabrication method, each tool exhibits its own characteristic profile feature and surface roughness. Polystyrene and polycarbonate substrates embossed with the electroformed tool exhibited lowest surface roughness of 48 nm compared to 450 nm for the laser machined tool. The embossed microfluidic chips were tested for fluid flow and electrospray and showed good performance.     

Printing 3D microfluidic chips with a 3D sugar printer

This study demonstrated how to quickly and effectively print two-dimensional (2D) and three-dimensional (3D) microfluidic chips with a low-cost 3D sugar printer. The sugar printer was modified from a desktop 3D printer by redesigning the extruder, so the melting sugar could be extruded with pneumatic driving. Sacrificial sugar lines were first printed on a base layer followed by casting polydimethylsiloxane (PDMS) onto the layer and repeating. Microchannels were then printed in the PDMS solvent, microfluidic chips dropped into hot water to dissolve the sugar lines after the PDMS was solidified, and the microfluidic chips did not need further sealing. Different types of sugar utilized for printing material were studied with results indicating that maltitol exhibited a stable flow property compared with other sugars such as caramel or sucrose. Low cost is a significant advantage of this type of sugar printer as the machine may be purchased for only approximately $800. Additionally, as demonstrated in this study, the printed 3D microfluidic chip is a useful tool utilized for cell culture, thus proving the 3D printer is a powerful tool for medical/biological research.     

直接式单片机扫频信号源

本文介绍一种由四片７４１６７同步十进制系数乘法器构成的正弦波扫频信号发生器。频率范围０．１￣９９９９Ｈｚ，频率分辨率为０．１Ｈｚ。频率值，扫频方式和扫频速率均可由键盘输入。电路用５．１２ＭＨｚ的石英晶体振荡器作为主频发生器，采用了频率跟踪低通滤波器。其波形失真度很小，约为０．３％。     

Tibidabo: Making the case for an ARM-based HPC system

It is widely accepted that future HPC systems will be limited by their power consumption. Current HPC systems are built from commodity server processors, designed over years to achieve maximum performance, with energy efficiency being an after-thought. In this paper we advocate a different approach: building HPC systems from low-power embedded and mobile technology parts, over time designed for maximum energy efficiency, which now show promise for competitive performance.We introduce the architecture of Tibidabo, the first large-scale HPC cluster built from ARM multicore chips, and a detailed performance and energy efficiency evaluation. We present the lessons learned for the design and improvement in energy efficiency of future HPC systems based on such low-power cores. Based on our experience with the prototype, we perform simulations to show that a theoretical cluster of 16-core ARM Cortex-A15 chips would increase the energy efficiency of our cluster by 8.7×, reaching an energy efficiency of 1046 MFLOPS/W.     

How to make your own processor architecture (review of Processor Design: System-on-Chip Computing for ASICs and FPGAs by Nurmi, J., Ed.; 2007) [Book reviews]

This is a review of Processor Design: System-on-Chip Computing for ASICs and FPGAs (edited by Jari Nurmi). Because processors are now embedded in SoCs and programmable devices, a system designer is not limited to chips available from major manufacturers. The theory is that a system built of specialized processors will be more efficient, and this book covers a wide range of such customized computer architectures. The book includes three main types of chapters. The first group consists of background information; the second focuses on stages of the processor design process; and the third includes examples of architecture types and experimental architectures, mostly from universities.