Stacking for chip security
"With the new technology, the top sides of the chips are inside the 3-D stack and therefore not accessible to mechanical attacks, electrical probing or a lot of other physical attacks," says Wolfgang Gruber of Infineon Technologies, the German lead partner.
The Austrian partner Datacon developed the machinery to construct the 3-D chips. The project developed two versions of the 3-D stacking.
The first technology will be ready for production in 2004. This is a cost-efficient, two-layer technology called 'Solid Face to Face' (F2F), in which one or more chips are attached to a base chip by a soldering process. A demonstration chip card has been built with a large amount of memory capable of fulfilling requirements for future multi-application operating systems.
Work continues on a second version - a multi-layer technology based on F2F that will allow for wiring through a chip to the next chip, thus making stacks of three or more layers possible and further increasing the chip’s flexibility and security. This is due for production in 2007.
