Search results

A review of state‐of‐the‐art technology pertinent to tape automated bonding (for fine pitch, high I/O, high performance, high yield, high volume and high reliability) is presented. Emphasis is placed on a new understanding of the key elements (for example, tapes, bumps, inner lead bonding, testing and burn‐in on tape‐with‐chip, encapsulation, outer lead bonding, thermal management, reliability and rework) of this rapidly moving technology.

This paper discusses the increasing activity being directed towards microminiature multichip module packaging. It shows new substrate materials that are being investigated, including multilayer thin‐film ceramics and silicon wafers. Wire bonding, tape‐automated bonding (TAB), and flip device termination techniques are covered. Particular attention is given to the use of multichip modules for advanced data processing applications.

As requirements for system performance and density increase, more attention is being given to chip‐on‐board (COB) packaging techniques. COB is ‘surface mount packaging taken to the extreme’ as it involves the direct mounting of bare semiconductor die to printed circuit board substrates. In this paper, the ‘thermal resistance’ of a single COB package is proposed. An analytical model for this resistance is developed for a multilayer board configuration using a combination of Fourier transform and adjoint‐solution techniques. Parameters in the model include the chip and board geometric parameters, individual layer unit conductances, and top and bottom surface film coefficients. A series of curves are developed from the model. These curves may be used in the initial design process to determine, for example, required film coefficients and the efficacy of adding thermal planes to the board. The model is also used to test the adequacy of the ‘effective series conductivity’ of a multilayer board.

The need for better performance, safety and comfort is the driving force behind the dramatic growth in car electronics. The key to success depends mainly on system reliability and cost which in turn are related to the choice of technological approach. The basic topics to be investigated are, on the one hand, system architecture and, on the other, the implementation techniques involved. Large scale integration of a consistent portion of the system will be necessary but other factors such as interconnections, packages and so on must also be taken into account. The variety of boards, components and assembly techniques currently available are just adequate for present needs, but for the 1990s the continuously increasing complexity of automotive electronic systems will probably necessitate better use of what is available and possibly new ideas.

This paper deals with the design of PCBs, using the dielectric properties of solder mask as an insulation layer to protect boards and components; the elimination of selective solder filling of component holes; the protection of via holes during soldering, and the preparation of artwork, with particular attention to design tolerances using dry film solder mask. Future prospects in PCB design, employing dry film solder mask, are also discussed.

A three‐dimensional (3D) package consisting of a stack of three silicon chips was conceptually designed. A finite element simulation of this 3D package was conducted in order to compare the fatigue lives of the solder joints with those in a typical single flip chip package when subjected to a cyclic thermal loading. It was found that the proposed design of the 3D package was feasible in terms of its mechanical deformation response to the thermal cycle.

The opportunity for mutual benefit across Europe to develop low‐cost MCM technologies arose from recognition of the scientific skills and design and prototyping capabilities in organic and inorganic circuits in countries of Central Europe. As a result, the leading research institutions and small/medium‐size enterprises of Hungary, Romania and Slovenia together with relevant institutions of the UK and Belgium proposed and received approval for a European Union INCO‐Copernicus project “Cheap multichip models” to establish fast prototyping low cost multichip module (MCM) technology facilities. The project commenced in May 1997.

The purpose of this paper is to determine arsenic, cadmium and lead contents of rice imports and to estimate their impact on these heavy metal intakes in Qatar.

In total, 30 rice samples imported from various countries (Vietnam, Thailand, India, Pakistan, the USA, Australia, the UK and Lebanon) were analyzed for arsenic, cadmium and lead contents with plasma optical spectrometer. These heavy metal intakes from rice were estimated for Qatar population based on the per capita consumption of rice as per 2018 rice consumption data.

In all rice samples, mean concentrations of arsenic, cadmium and lead were 1.11 mg/kg, 19.7 µg/kg and 131.3 µg/kg, respectively. Average arsenic, cadmium and lead contents were the highest in rice imported from Thailand (1.25 mg/kg), Vietnam (30 µg/kg) and India (178.3 µg/kg), respectively. Estimated arsenic, cadmium and lead intakes through rice consumption by Qatari population were 225.7, 4 and 26.7 µg/day, respectively.

In all rice imports, arsenic content is approximately 5.5 times higher than the maximum allowable concentration (MAC), whereas the cadmium and lead levels are within the MAC. Because these heavy metals are linked to health, all Middle Eastern countries that import rice from Thailand, Vietnam and India should monitor the metal contents in their food supply on a regular basis.

The study here responds to the view that the crucial problem in strategic management (research) is firm heterogeneity – why firms adopt different strategies and structures, why heterogeneity persists, and why competitors perform differently. The present study applies complexity theory tenets and a “neo-configurational perspective” of Misangyi et al. (2016) in proposing complex antecedent conditions affecting complex outcome conditions. Rather than examining variable directional relationships using null hypotheses statistical tests, the study examines case-based conditions using somewhat precise outcome tests (SPOT). The complex outcome conditions include firms with high financial performances in declining markets and firms with low financial performances in growing markets – the study focuses on seemingly paradoxical outcomes. The study here examines firm strategies and outcomes for separate samples of cross-sectional data of manufacturing firms with headquarters in one of two nations: Finland (n = 820) and Hungary (n = 300). The study includes examining the predictive validities of the models. The study contributes conceptual advances of complex firm orientation configurations and complex firm performance capabilities configurations as mediating conditions between firmographics, firm resources, and the two final complex outcome conditions (high performance in declining markets and low performance in growing markets). The study contributes by showing how fuzzy-logic computing with words (Zadeh, 1966) advances strategic management research toward achieving requisite variety to overcome the theory-analytic mismatch pervasive currently in the discipline (Fiss, 2007, 2011) – thus, this study is a useful step toward solving the crucial problem of how to explain firm heterogeneity.

Developments in the social neurosciences over the past two decades have rendered problematic the main knowledge elicitation techniques currently in use by strategy researchers, as a basis for revealing actors’ mental representations of strategic knowledge. Extant elicitation techniques were advanced during an era when cognitive scientists and organizational researchers alike were preoccupied with the basic information of processing limitations of decision makers and means of addressing them, predicated on an outmoded conception of strategists as affect-free, cognitive misers. The need to adapt these techniques to enable the investigation of the emotional content and structure of actors’ mental representations is now a pressing priority for the advancement of theory, research, and practice pertaining to several interrelated areas of strategic management, from dynamic capabilities development, to upper echelons theory, to strategic consensus formation. Accordingly, in this chapter, we report the findings of two studies that investigated the feasibility of adapting the repertory grid, a robust method, widely known and well used in strategic management, for this purpose. Study 1 elicited a series of commonly mentioned strategic issues (the elements) from a sample of senior managers similar in composition to the sample recruited to the second study. Study 2 participants evaluated the elements elicited in Study 1 in relation to a series of researcher-supplied bipolar attributes (the constructs), based on the well-known affective circumplex model of human emotions. In line with expectations, a series of vector-based multivariate analyses revealed a number of interesting similarities and variations among participants in terms of the basic structure and emotional salience of the issues under consideration.