Surface-mount technology printed-circuit boards

Pricing as well as reliability considerations have led to an almost exclusive use of Si-based (i.e. Si and SOI) micro machined devices. Packaging and assembly has focused on ceramics (A1203, AIN, Low Temperature Co-fired Ceramics LTCC), Printed Circuit Board (PCB-) and Surface Mount Device (SMD-) technology and multichip modules (MCM s). 

The electronic unit of the LAPS device can be created on a double-sided printed circuit board with the help of surface-mounted technology to bring it as close as possible to the sensor chip. The integrated electronic unit enables an easy access to the different measurement spots and provides an amplified, filtered and easily measurable (converted) voltage signal (several V) with respect to the sensor signal (several pA). The electronic unit contains different blocks, which are described in Fig. 6.2. 

In order to miniaturize products and to improve productivity in the electronics industry, a method of soldering resinous electronic parts has been developed for affixing parts, such as connectors, switches, relays and coil bobbins to printed circuit board (PCB). This method is addressed as surface-mount technology. 

Microfluidic Boards Microfluidic board interconnection technologies seek to mimic the electronic printed circuit board for ease of use, reliability, and versatility. In microfluidic board technologies, the substrate contains the passive microfluidic channels and reservoirs, with active components (e.g., sensors, valves) mounted on top (e.g.. Ref. [2]) (see Fig. 1) similarly to electronic components mounted on a printed circuit board (PCB) or multichip modules (MCM) in surface-mount technologies (SMT). Electronic coimections between components are provided on top of the board, while fluidic interconnection is usually provided in the board material itself. Microfluidic circuit boards can be made from a variety of materials, including silicon, glass, and polymers, e.g., polydimethylsiloxane (PDMS), epoxy, or polymethyl methacrylate (PMMA). Microfluidic boards can be as simple... 

Bono, D., The Assessment of the Corrosivity of Soldering Flux Residues Using Printed Copper Circuit Board Tracks, Solder Surface Mount Technology, No. 2, June 1989, pp. 22-29. 

With the growing use of surface mount technology and related techniques such as chip-on-board, printed circuit board manufacturers are continually seeking new processes to enable production of boards with increased circuit densification and decreased circuit feature sizes. Consequently, line widths are now approaching those of early semiconductor devices, and this has in turn placed new demands on the resolution capabilities of the inner-layer and outer-layer photoresists used in the industry. 

In addition to wire harness connectors, printed circuit board-attached connectors, for automotive or electronic applications, also benefit from many of SPS s performance characteristics, including low viscosity, which helps to fill thin walls and heat resistance to maintain dimensional stability through lead-free reflow soldering operations (see Table 15.2). The trend toward miniaturization in automotive electronic control modules has increased the need for compact surface mount connector technology, as opposed to bulkier through-hole and wave-soldered alternatives. 

For nearly 30 years, SMT has remained the only dedicated resource for the surface mount technology industry. Recognized as the leader in comprehensive knowledge base for assembly of printed circuit boards, electronics and the materials critical to the process, readers represent the core and leadership of the surface mount industry. 

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