Microelectronics International

Pryputniewicz, Ryszard J.; Rosato, David; Furlong, Cosme

2003 Microelectronics International

doi: 10.1108/13565360310455463

Integrity of surface mount technology SMT components depends on their response to temperature changes caused by operating conditions. Temperature induced differential thermal expansions lead to strains in the interconnection structures of active devices. To evaluate these strains, temperature profiles of the interconnected components must be known. In this paper, a methodology for developing thermal models of SMT components is presented using thermal analysis system TAS and its application is demonstrated by simulating thermal fields of a representative package. Then, thermomechanical deformations of the package are measured quantitatively using stateoftheart laserbased optoelectronic holography OEH methodology.

Tian, Zhengrong; Free, Charles; Aitchison, Colin; Barnwell, Peter; Wood, James

2003 Microelectronics International

doi: 10.1108/13565360310455472

The trend in wireless and mobile communications for broader bandwidth microwave circuitry, coupled with high packaging density and low cost fabrication has triggered investigations of new circuit configurations and technologies that meet these requirements. We have addressed these issues through the study of multilayer microwave structures using advanced thickfilm technology. The techniques described employ several layers of metal sandwiched by thickfilm dielectric. This leads to an efficient solution for system miniaturisation. The significance of this work is that it shows the multilayer approach to microwave structures, coupled with new thickfilm technology, offers a viable and economic solution to achieve highdensity, highperformance microwave circuits.

Bell, Patrick; Hoivik, Nils; Bright, Victor; Popovic, Zoya

2003 Microelectronics International

doi: 10.1108/13565360310455481

A frequency tunable halfwave resonator at 3GHz is presented with a microelectromechanical systems MEMS variable capacitor as the tuning element. The capacitor is fabricated using the multiuser MEMS process MUMPs technology provided by JDSCronos, and transferred to an alumina substrate by an inhouse developed flipchip process. This capacitor is electrostatically actuated. The resulting CV response is linear with a slope of 0.05pFV for a wide range of actuation voltages. The MEMS device has a capacitance ratio of 31 for 070V bias, with a Qfactor of 140 measured at 1GHz. A halfwave tunable microstrip resonator with bias lines is designed to include this MEMS device, which exhibits linear tuning over 180MHz 6 percent centered around 3GHz with a constant 3dB bandwidth of 160MHz over the entire tuning range. The power consumption of the MEMS device was measured to be negligible.

Carchon, G.J.; De Raedt, W.; Beyne, E.

2003 Microelectronics International

doi: 10.1108/13565360310455490

High Q onchip inductors and low loss onchip interconnects and transmission lines are an important roadblock for the further development of Sibased technologies at RF and microwave frequencies. In this paper, inductors are realized on standard Si wafers 20.cm using MCMD processing. This consists of realizing two low K dielectric layers BCB and a thick Cu interconnect layer. Inductors with 5m lines and spaces are demonstrated for a 5m thick Cu layer, hereby leading to a very compact and high performance inductors Qfactors in the range of 25 to 30 have been obtained for inductances in the range of 1 to 5nH. It is also shown how the Qfactor and resonance frequency vary as a function of the inductor layout parameters and the thickness of the BCB and Cu layers. The realized 50 CPW lines lateral dimension of 40m have a measured loss of only 0.2dBmm at 25GHz.

Zheng, Yulan; Atkinson, John; Zhang, Zhige; Sion, Russ

2003 Microelectronics International

doi: 10.1108/13565360310455508

Novel thick film strain gauges have been constructed using a zaxis orientation on insulated stainless steel for a variety of force sensing applications. These devices exhibit high gauge factor and good thermal stability compared with conventional xaxis devices and offer other mechanical advantages due to their mode of operation. The work reported here investigates the characteristics of different types of stainless steel substrate and different types of insulating material used in the construction of the sensors. Both ferritic and austenitic steels have been investigated, together with different resistive and insulative compositions. The temperature coefficient of resistance of the devices has been shown to be a complex function of device thickness, surface area and the difference between the thermal coefficients of expansion of the various materials employed.

Rooney, Daniel T.; Todd Castello, N.; Cibulsky, Mike; Abbott, Doug; Xie, Dongji

2003 Microelectronics International

doi: 10.1108/13565360310455517

The mechanical integrity of solder joint interconnects in PWB assemblies with micro BGA, chip scale, and LGA packages are being questioned as the size and pitch decrease. Threepoint cyclic bend testing provides a useful tool for characterizing the expected mechanical cycling fatigue reliability of PWB assemblies. Cyclic bend testing is useful for characterizing bending issues in electronic assemblies such as repetitive keypad actuation in cell phone products. This paper presents the results of threepoint bend testing of PWB assemblies with fine pitch packages. The methodology of materials analyses of the metallurgy of solder interconnects following mechanical bending and thermal cycle testing is described.

Lalinsky, T.; Hak, S.; Mozolov, .; Burian, E.; Krn, M.; Tomka, M.; kriniarov, J.; Drzk, M.; Kostic, I.; Matay, L.

2003 Microelectronics International

doi: 10.1108/13565360310455526

A new micromachining technology of mechanically fixed and thermally insulated cantilevers, bridges and islands was developed to be used for design of GaAs heterostructure based microelectromechanical systems MEMS devices. Based on the micromachining technology, two different MEMS devices were designed and analyzed. The first one was micromechanical thermal converter MTC and the second one was a micromechanical coplanar waveguide MCPW. The basic electrothermal as well as microwave properties of the MEMS devices designed are investigated. The results obtained are also supported by simulation. The advantages of the fixed micromechanical structures in the field of design of new MEMS devices are discussed.

Wang, Y.L.; Carroll, A.F.; Smith, J.D.; Cho, Y.; Bacher, R.J.; Anderson, D.K.; Crumpton, J.C.; Needes, C.R.S.

2003 Microelectronics International

doi: 10.1108/13565360310455535

Substrates with high thermal conductivity continue to be in great demand for their ability to enable smaller and denser high power circuits. BeO has been used for this purpose for many years with thick film materials. However, due to health and environmental concerns with BeO, many manufacturers feel compelled to switch to alternative substrates. This paper will discuss a thick film system consisting of conductors, dielectric, and resistors developed specifically for use with the most likely alternative, AlN substrates. This system will soon find broad use in applications such as power resistors for telecom, optoelectronic submounts, and highpower automotive applications.

Lakeman, Charles D.E.; Fleig, Patrick F.

2003 Microelectronics International

doi: 10.1108/13565360310455544

As the number of passive components in electronic circuits increases, new methods for fabricating passives are under development to optimize utilization of board space. In this paper, we will describe the performance capabilities of TPL's microcontact printing CP process to fabricate nearnetshape structures with feature sizes ranging from 100 microns to the submicron scale. Like thick film processes, this novel process is compatible with a broad materials base, making a large range of materials properties available. Unlike thick film, however, this novel process employs powderfree inks that can be patterned with high resolution. It is anticipated that this process will enable integration of passive components that show thin film performance at thick film cost. Emphasis in this paper will be placed on processing conditions, and materials properties to demonstrate the feasibility of this process for passive device fabrication.