Ultra-thin electronic device package

Abstract

We report in this article a feasibility study of ultra-thin device packages. These packages combine thin integrated circuit chips, thin flex circuitry, and adhesive flip-chip technologies. Using this novel packaging concept, we constructed 512 kb SRAM memory modules that were less than 150 micron thick. Even more profound, the package was flexible enough to conform to nonplanar surfaces. This unique property can lead to new applications that would not be feasible otherwise and extend the reach of electronics into brand new areas. Two of these ultra-thin modules were stacked to construct a 3-D package with 1 Mbyte of memory capacity that is approximately 30 times thinner and 30 times lighter than a conventionally packaged device.Index Terms-Adhesive flip-chip bonding, flexible, packaging, thin IC, 3-D.

Flexible active electrode arrays with ASICs that fit inside the rat’s spinal canal

“…Several approaches have been proposed for the assembly of thin electronics on flexible substrates. These include flip chip bonding by means of reflow soldering, thermocompression processes (Banda et al 2008 ; Zhang et al 2009 ) and polymeric adhesives (Chen et al 2000 ), gold electroplating (Govaerts et al 2009 ), as well as conductive pastes (Marinov et al 2012 ).…”

Laser-assisted ultrathin die packaging: Insights from a process study

“…The flexible substrate requires not only small but also flexible bare dice. This can be achieved only if the thickness of the silicon is reduced to 50 lm or less [1,2] thus adding flexibility to the intrinsically fragile bare dice. For example, the allowable bend radius for a 25-lm thick silicon wafer is as small as 1 cm [3].…”

Realizing flexible bioelectronic medicines for accessing the peripheral nerves – technology considerations

“…Flip-chip bonding has been extensively used on flexible substrates in several variations, including reflow soldering and thermocompression processes for thin dice (50 μm) (Banda et al 2008;Zhang et al 2009), but dispensing the underfill without allowing the material to flow on top of the very thin die is challenging. Polymeric adhesives are also very popular for flip-chip bonding on flexible substrates (Lai and Liu 1999;Chen et al 2000;Lu and Chen 2010;Chiang et al 2006;Chuang et al 2010) as they can eliminate the need for underfill. The adhesive acts as the interconnection medium between the bumped chip and the substrate, while it at the same time protects the contacts and provides mechanical support.…”