Conventional chip carrier

Figure 2. Conventional chip carrier. This example with a lid is for hermetic applications. (Reproduced with permission from Ref. 4. Copyright 1988 BPA [Technology and Management, Ltd.].)...

With the conventional technology, ICs are mounted individually in plastic or ceramic single-chip packages (SCPs), such as dual-in-line packages (DIPs) or chip carriers, and the SCPs are interconnected on printed wiring boards (PWBs). The number of pins on SCPs has increased significantly, and line widths on PWBs, like IC feature sizes, have followed a historical downward trend (2). However, the basic SCP-on-PWB approach has remained predominant. 

The requirements for advanced military MLBs are shown in Table I. One of the major problems of using leadless ceramic chip carriers in advanced avionics (VHSIC and VLSI) applications is the mismatch between the CTE of alumina chip carriers (6.4 ppm/°C) or silicon (3 ppm/°C) and conventional glass/epoxy substrates (12 to 17 ppm/°C). This mismatch results in work-hardening and cracking of solder joints which attach the devices to the substrate. 

Applications and uses electrical and electronic parts (connectors, sockets, chip carriers), mechanical parts, food containers, automotive underhood parts, and chemical processing, household cookware for conventional and microwave ovens. 

ACAs have been investigated as replacement for SnPb solder in surface mount (SM) attachment for fine pitch applications. The key attractive advantage is the cost effectiveness of using ACA to bond fine pitch SM components. A limitation of ACAs is the need to cure imder a contact pressin-e. The concept of using an ACA as a solder replacement on rigid chip carriers ntiUzing conventional SMT... 

Rather than witnessing radical breakthroughs, the market has seen a steady improvement in the availability of software and hardware tools that provide for the effective combination of the best features of conventional test systems and increased availability of test systems dedicated to specialty markets, in particular the small-format laminated chip carrier prodnct type. 

Single Inline Memory Module (SIMM) Individual RAM chips are soldered or surface mounted onto small narrow circuit boards called carrier modules, which can be plugged into sockets on the motherboard. These carrier modules are simple to install and occupy less space than conventional memory modules. 

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