Here is the abstract you requested from the IMAPS_2012 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Rediscovering Multilayer Rigid-Flex with Z-interconnect Technology|
|Keywords: rigid-flex, Z-interconnect, embedded actives|
|Steadily increasing interest in rigid-flex stems from its unique promise to enable new applications for military and high-end electronics. Compared to traditional rigid substrates, rigid-flex has several advantages. First, rigid flex gives the ability to design circuitry to fit the physical space, rather than adjusting the physical space to fit the circuit board. Second, Rigid Flex circuit can save space and weight. Replacement of conventional substrates with rigid-flex structures allows for 3D interconnects that are formable, that is, can more readily assume the shape of the housing into which they are designed to be inserted, facilitating a more space-efficient package design. Rigid-flex allows designers to replace multiple substrates interconnected with connectors, wires, and ribbon cables with a single package offering improved performance, reliability, and a potential cost-effective solution However, processing and materials selection is critical in order to achieve high quality multilayer, rigid-flex structures. To date, there is no technology available which can economically produce high density multilayer rigid-flex with rigid or flex originating from any layer in the stack. In the present study, a novel strategy allowing for multi-layer rigid flex structures is reported. Specifically, metal-to-metal z-axis electrical interconnection among the flexible and rigid elements during lamination to form a single package rigid-flex structure is described. Conductive joints are formed during lamination using an electrically conductive adhesive (ECA). As a result, structures can be fabricated with multiple flexible elements at any arbitrary layer. The z-interconnect based rigid-flex structures offer many advantages over the more conventional structures, for example:a reduction in total processing steps,maximum possible metal layer counts, placement of rigid elements and flex elements in any layer, opportunity for multiple flex layers and ability to connect multiple multilayer rigid substrates Several classes of flexible materials, including polyimides, PTFE, liquid crystal polymer (LCP), have been used to develop high-performance rigid-flex packages. Rigid-flex packages with embedded passives and actives are also being investigated. Collectively, the results suggest that multilayer flexible packages and rigid-flex packages are attractive for a range of applications, not only where flexibility is required, but also in large-area microelectronics such as radiofrequency structures, medical devices, and aerospace and defense applications.|
|Rabindra Das, PRINCIPAL ENGINEER
Endicott Interconnect Technologies, Inc.