Kurzfassung Das Optimieren der mechanischen und tribologischen Eigenschaften keramischer Schichten basierte auf den Ergebnissen von Vorversuchen, in denen überwiegend Agglomeratpulver der Systeme Al2O3/TiO2 bzw. Al2O3/ZrO2 zur Anwendung gekommen sind. Das Erreichen der erforderlichen Oberflächenqualität der plasmagespritzten Schichten erfolgte durch eine Schleif- und Polierbearbeitung. Die Untersuchungsergebnisse der Haftfestigkeit und des gravimetrischen Verschleißes der Schichten zeigen, dass die Mischkeramiken Al2O3(70%)/TiO2(30%) und Al2O3(57,5%)/ZrO2(42,5%) die Favoriten für eine weiterführende Schichtoptimierung darstellen. Die Optimierung der Schichtstruktur und -eigenschaften beinhaltet im Schwerpunkt das weitere Homogenisieren der Schichtmorphologie bei gleichzeitiger Erhöhung der Adhäsion.

The optimization of mechanical and tribilogical properties of ceramic coatings is based on screening tests. There fore agglomerated powders of systems Al2O3/TiO2 and Al2O3/ZrO2 were used. After plasmaspraying the requested quality of surface will be reached by grinding and polishing. The coating systems Al2O3(70%)/TiO2(30%) and Al(2)o(3)(57,5%)/ZrO2 (42,5%) are favorized, based on evaluation of tensile and tribological test results. The further optimization is focussed on improving the homogenization of morphology and adhesion.

Cross correlation analysis of digitised grey scale patterns is based on - at least - two images which are compared one to each other. Comparison is performed by means of a two-dimensional cross correlation algorithm applied to a set of local intensity submatrices taken from the pattern matrices of the reference and the comparison images in the surrounding of predefined points of interest.Established as an outstanding NDE tool for 2D and 3D deformation field analysis with a focus oil micro- and nanoscale applications (microDAC and nanoDAC) the method exhibits an additional potential for far wider applications, that could be used for advancing homeland security.Cause the cross correlation algorithm in some kind seems to imitate some of the "smart" properties of human vision, this 'field-of-surface-related" method can provide alternative solutions to some object and process recognition problems that are difficult to solve with more classic "object-related" image processing methods. Detecting differences between two or more images using cross correlation techniques can open new and unusual applications in identification and detection of hidden objects or objects with unknown origin, in movement or displacement field analysis and in some aspects of biometric analysis, that could be of special interest for homeland security.

The growing application of advanced electronic packages under harsh environmental conditions, extreme temperatures especially in automotive applications is often a reason for damage, fatigue, and failure of entire components and systems. Consequently, their thermo-mechanical reliability is one of the most important preconditions for adopting these technologies in industrial applications. To prevent chips from being exposed to the external environment integrated circuits are usually encapsulated into packages. As a result, a microelectronic package is basically a compound of several materials with quite different Young's moduli and thermal expansion coefficients. Additionally, various kinds of inhomogeneity, residual stresses from several steps of the manufacturing Process contribute to interface delaminations, chip cracking, and fatigue of solder interconnects. This paper intends to investigate mixed mode interface delamination phenomena in micro components by using combined numerical investigations by means of nonlinear FEA and experimental investigations. It explains how experimental data were used as input for the quantitative evaluation of fatigue and fracture of microcomponents. Both numerical and experimental investigations provide the basis for understanding and evaluating failure mechanisms especially in solder joints, as well as several polymer material interfaces, and should support further applications for raising the thermo-mechanical reliability of advanced electronic packages.

Es wird eine Methode zur Untersuchung von Grenzflächenfestigkeit und Delaminationsprozessen sowie zur Beschreibung von Rissentstehung und Rissfortschritt in Verbundmaterialien vorgestellt. Mit dem optischen Messverfahren UNIDAC (Universal Deformation Analysis by Correlation) können lokale Verformungen und Verformungsfelder erfasst und beschrieben werden. Die bei mechanischer Belastung der Proben auftretenden Veränderungen werden mit einer optischen Technik erfasst und die bei unterschiedlichen Laststufen aufgenommenen digitalisierten Bilder mittels eines geeigneten Korrelationsalgorithmus „verglichen”. Damit kann sowohl das Deformationsverhalten des Materials als Ganzes sowie einzelner Bereiche des Verbundes und seiner Komponenten beschrieben und Aussagen über das Verhalten der Grenzschichten bei Belastung abgeleitet werden. Die lokalen Verschiebungsfelder innerhalb einzelner Komponenten werden getrennt erfasst und der Rissfortschritt kann direkt verfolgt werden. Die vorgestellten Ergebnisse beruhen auf der Kombination zwischen dem UNIDAC-Verfahren und dem Dreipunktbiegetest. Aus den Messwerten können weitere Werkstoffkenngrößen abgeleitet werden.

The growing use of advanced electronic packages under harsh environmental conditions including extreme temperatures is often a reason for damage, fatigue and failure of entire components and systems. Therefore, their thermo-mechanical reliability is becoming one of the most important preconditions for adopting it in industrial applications. Various kinds of inhomogeneity, residual stresses from several steps of the manufacturing process as well as the fact that microelectronic packages are basically compounds of materials with quite different Young's moduli and thermal expansion coefficients contribute to interface delamination, chip cracking and fatigue of solder interconnects. This paper intends to contribute to the investigation of mixed mode interface delamination phenomena in micro components by using combined numerical investigations by means of nonlinear FEA, several fracture mechanics concepts and experimental investigations using a gray scale correlation method. Interfacial fracture toughness tests commonly utilized are investigated in order to check their characteristics and, in particular, efficiency.

Electrodeposition processes were proposed for the fabrication of micro-electro-mechanical systems (MEMS) long time ago. Patterned layers of nickel, nickel alloys, gold alloys, silver and copper are used to realize micro switches, relays, valves, pumps, coils and gyroscopes. The metal layers have to meet the highest requirements on homogeneity, as well as on mechanical, electric or magnetic characteristics. The application of microelectroplating has to cope with specific effects influencing the electroplating conditions in the micrometer range. So, many efforts concentrate on the control and standardisation of microelectroplating processes. The suitability and application of electroplating methods will be exemplified by two concepts of a microrelay assigned for current loads of up to several amperes. The development of these microrelays is object of the project “MikroRel”, partially funded by the German ministry for education and research (BMBF).

CSP and FC assemblies from mechanical point of view are typically rakish compounds of silicon, polymeric materials, ceramics and metals. While ceramics and silicon show a mainly elastic behavior, metals and polymerics show a plastic, viscoelastic and/or viscoplastic behavior which is often highly depend on the temperature. Additionally, polymeric material come with a glass transition temperature which is often inside the temperature range of interest. Unfortunately, the most damaging thermomechanical characteristic of polymerics is the much higher thermal expansion coefficients compared to that of silicon, ceramics or metals. These special qualities in combination with various kinds of inhomogeneities and shape owed stress singularities lend to interface delaminations, chip cracking and fatigue of solder joints and in contrast to the goal of the often complex structure, to a thermo-mechanical reliability lower than expected, While life time estimations due to the thermal fatigue of solder joints (typically based on Coffin-Manson type equations) become more and more reliable, the evaluation of the fracture behavior of different material interfaces is of a much lower quality. Therefore, this is an obstacle for comprehensive thermo-mechanical reliability investigations of electronic packages today.Consequently, the contribution shows the use of non-linear finite element simulations with respect to the non-linear, temperature and rate dependent behavior of different materials used, tile application of fracture mechanics concepts (energy release rate, integral fracture approaches, mode-mixity examinations) in combination with experimental investigations. For these purpose, bending specimens consisting of several materials interfaces widely used in FC assemblies have been investigated in particular. In order to evaluate the different approaches used some results have been compared to micrographs from growing interface delaminations by using micro deformation measurements on the basis of a gray scale correlation method applied to micrographs, in particular.

Cracking in various interfaces is a significant concern for yield loss and reliability of advanced packages. There are many reasons for interface damage, for example, low adhesion due to incompatible interfaces or due to contamination. Delamination at the encapsulant-substrate or chip-substrate interfaces can lead to cracking of the electrical interconnents.To assess the integrity of the interface, the following information is necessary: the interfacial adhesion, a pertinent simulation model, and an estimate of the maximum length of a permissible initial crack.In this paper a method is discribed to investigate the interface strength and the process of delamination and to pursue crack initiation and crack propagation. The 3-point-bending-test is combined with the optical measuring procedure DAC (Deformation Analysis by Correlation), a method of digital image processing. Digitized images of the specimen under different bending load steps are compared by a correlation algorithm. This allows to determine and to evaluate the local displacements and displacement Welds.The investigations of local displacements and displacement fields by optical methods in combination with a Finite Element Analysis lead to a better understanding of crack intiation and crack propagation and consequently to detailed knowledge about package stability.

This paper deals with the combination between material testing and the optical measuring procedure UNIDAC (Universal Deformation Analysis by Correlation). This method can be used to present and describe the deformation without special preparations of the specimen surface. It will be presented at an example of investigation with an elastomer, a paper and a fibre material.

An improved understanding of material behaviour under mechanical and/or thermal load depends on more detailed information from testing devices. Demands exist in particular for obtaining directly displacement and strain fields from testing equipment. For this purpose experimental methods and computer codes have been developed. Structured images are recorded in situ from test specimens at different load states. Subsequent optical or computer correlation treatment leads to in-plane deformation fields. Advantages of the approach are simple experimental equipment and the possibility to apply the method to high temperature problems. Furthermore, transient processes can be recorded on TV tape and processed afterwards. Results from fracture mechanics studies, from static, moderately dynamic and impact loaded specimens and also from composite material analysis are reported. The down scaling capability of the computer-based correlation method is demonstrated by displacement field measurements on microelectronics specimens within electron microscopes.

The technology of surface acoustic wave (SAW) devices allows the integration of signal processing and sensor functions within one product. In the past, SAW sensors have been operated at room temperature or 100/spl deg/C-200/spl deg/C at most, material-related problems become obvious if one attempts to increase this operating temperature to a value as high as 1000/spl deg/C. First experimental results are presented based on a variation of the metallization and the use of diffusion barriers. It is expected that the use of these specially tailored materials with particular functional properties will lend to a considerable improvement of the lifetime and reliability of SAW sensors and the development of devices resistant to high temperatures as well as high pressures and chemically aggressive environments. The high-temperature characteristics of such novel devices are investigated by finite-element simulation and by experimental deformation analysis. Which assembly, interconnection, and packaging techniques are applicable at 1000/spl deg/C are also discussed.

AbstractSiC‐Barriereschichten auf Kohlenstoffasern lassen sich durch thermische Zersetzung von Methyltrichlorsilan abscheiden. Der Einfluß der CVD‐Parameter auf deren Struktur und Zusammensetzung wird anhand der Ergebnisse von oberflächenanalytischen und elektronenmikroskopischen Untersuchungen dargestellt. Bei der Herstellung von faserverstärktem Al kommt es infolge von chemischen Reaktionen und Segregationen zur Bildung von unerwünschten Phasen an der Grenzfläche zwischen Matrix und Faser. die die Stabilität der Barriereschichten negativ beeinflussen.

SiC barrier layers on carbon fibers can be deposited by thermal decomposition of methyl trichlorosilane.The influence of the CVD parameters on their structure and composition is presented by the results of surface-analytical and electronmicroscopical investigations. During the preparation of fiber reinforced Al chemical reactions and segregation effects result in the formation of undesirabled phases at the interface between matrix and fiber.The stability of the barrier layer is negativly influenced by it.

Ceramic materials (SiC, TiC, TiB2) are deposited by chemical vapour deposition on carbon fibres for the reinforcement of aluminium. Coated fibres are then combined with aluminium by vacuum plasma spraying. The tensile strength of the coated fibres is measured and characterized by the Weibull distribution. Interface structure and the initial fibre surface are characterized by electron microscopy and microanalysis. It is found that the best chemical compatibility and strength are obtained with a dual coating of pyrolytic carbon and SiC.