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In this paper, the flight control system for sub-mini unmanned helicopter is discussed. The key technologies are introduced and some research work of Shanghai University about unmanned helicopter is presented. Sub-mini unmanned helicopters with the flight control system can perform aggressive maneuvers, its good performance and action as a flying robot and can be used in some particular circumstance
PZT transducer works on its nature frequency in the process of ultrasonic wire bonding. Its actual frequency characteristic needs to be investigated for best performance. A direct digital synthesizer (DDS) was used to sweep frequency for output transformerless (OTL) power amplifier. Actual input and output voltage of OTL power amplifier component was acquired and analyzed. The experiment shows that...
Smart card integrated circuits are never completely immune against any invasive attack (chemical, physical or energetic), and a hardware protection of the chip could be necessary. One solution consists in shielding the devices at the wafer level with a silicon structured cap (Sishelltrade). In order to increase security, this cap can also comport active functions. In this case electrical connections...
In this paper, a novel double-T-shaped microstrip resonator is presented, and its electromagnetic field distribution, resonant frequency and quality factor are computed and analyzed. A novel double-T-shaped microstrip bandstop filter is designed and its filter performance is simulated and analyzed as well. The results show that the filter has outstanding virtues such as wide bandwidth, high attenuation...
This paper presents the IP core design of PLC (programmable logic controller) microprocessor that includes a special Boolean process unit after analysing PLC programming language, instruction execution characteristics and current PLC disadvantage. The novel microprocessor based on RISC architecture for PLC accords with PLCs international standard and its systematic design requirement. It is successfully...
Compared to numerical methods, analytical solutions can offer a faster and more accurate procedure for obtaining the interfacial stresses in laminated structures. An analytical model for thermal stress analysis of multi-layered thin stacks on a thick substrate under isothermal loading is proposed in this paper. This analytical approach considers each layer as a beam-type plate with orthotropic material...
Anisotropic conductive adhesive (ACA) technology is one of the most important technologies for interconnect of electronics hardware. During the last 20 years, tremendous research and development effort has been spent on this. The purpose of this paper is to present ontology of the publications within the ACA technology since 1980. The following search fields are used for this study: ACA/ACF on glass,...
At present, solder joints are widely used to bond chips to their substrates for electronic connection and packaging. Good wettability is an essential requirement to form electronic interconnects. In this paper, an image acquisition system was used to observe time-dependent contact angle variation of 96.5Sn-3.5Ag lead-free BGA solder ball on Cu substrate. The wetting dynamics of the solder materials...
The formation and growth of intermetallic compounds (IMC) play a critical role in the solder joint reliability. In this study, joint assembly of high lead Sn-95Pb/Ni-Cu was employed to study the interfacial reaction and related IMC formation after aging at 150degC for 168, 500, 1000, 2000, and 3000 hrs, respectively. Special effort was focused on the investigation near the edge of solder joints. Field-emission...
With the rapid development of IC design methods and manufacturing technologies, the scale of IC is becoming lager and lager, and the design method of system on chip (SoC) has been widely adopted. In the design process of SoC, the test problem is viewed as the bottleneck of the SoC development; and it is a challenge to test the IP (intellectual property) cores which are embedded deeply in the SoC especially...
Along with the development of the multi-core system, the testability of circuit faces many new challenges. Relay wave propagation test of arrays (RWPA) has many advantages in single-chain and multi-chain boundary scan (BS) circuit. In this paper, the improved single-chain RWPA is tentatively applied to the multi-core BS architecture, to reduce the test time and increase the fault coverage. As an experiment,...
By applying vacuum physics to typical solder reflow vacuum packaging process of MEMS devices, the mathematical and physical model of the vacuum degree change of the cavity to be sealed in related with the gas absorption, desorption, penetration, flowage through little pipe and vapour pressure of materials was established and its arithmetic was ascertained with numerical simulation method. A software...
The versatile usages of smart cards with embedded display present a rigorous need in manufacturability and reliability. To increase the reliability and decrease the final cost, the work calls for co-design of the whole system which means that engineers have to consider the packaging scheme at the earliest stage of prototyping. Furthermore, the requirement of Chinese character based display requires...
This paper reviews sub 1.00mm ball pitch solder joint reliability (SJR) challenges under compressive loaded thermal cycling stressing. It focuses on different types of heat sinks and their compressive load effect on solder joint thermal fatigue performance. Heat sink configuration and compressive load applied was found to be important factors in determining failure region across ball grid array (BGA)...
When plastic packages undergo solder reflow after being subjected to moisture preconditioning, hygrothermal stresses are induced in the package. If these stresses are excessive popcorning failure will occur. It has been shown that popcorning failure is usually preceded by delamination of either the pad/encapsulant interface or the die-attach-layer/pad interface. Fracture mechanics methodology has...
With the further shrink of the IC dimension, the low K material has been widely used to replace the traditional SiO2 ILD in order to reduce the interconnect delay, the introduction of low k material into silicon imposed challenges on assembly wire bonding process which is further magnified with the shrink of the bond pad. In this paper, 44um fine pitch CMOS90 nm low k device is chosen to develop the...
This paper provides a review of the NAND and NOR flash memory technology and the market trend. Details on the market share and providers of NOR and NAND are included. Key considerations are focused on the various memory storage card formats, flash IC packaging and card assembly process. Manufacturing issues in the latest trend of further reducing the card size to mini- and micro-formats are discussed
The vibrations of chip and tool tip during thermosonic flip chip bonding were studied. By measure the vibration of the chip and tool tip with a Doppler laser vibration measure system, the "suddenly velocity decrease" of chip was elucited. It is noticed that this means the bonding strength formed in the bonding interface. By analyzing the vibration displacement and frequency of the chip and...
Nano-level smooth surfaces are used more and more in high and new technology production, and requirement of them is higher and higher. Traditional polishing methods keep the surface roughness from further reduction because of the existing of abrasive materials. Nano-machining polishing on metal materials with ice desk is an originality innovation polishing method. Polishing desk is made of ice desk...
Attachment of semiconductor devices to a package substrate is essential for providing electrical and structural connections as well as a heat dissipation path. The die-attach materials play a vital role in ensuring the system performance and reliability. As the electronics industry continues to integrate more functions in smaller packages, the electrical, thermal and mechanical properties of the existing...
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