The Hiding Dies Project


 
Published Sat, 2007-10-20 18:21 
 
 


Disembowel a mobile phone and the most prominent components on the  circuit 
board are the microchips, mounted inside plastic casings with metallic  feet 
protruding from the sides. But such bulky chip packages, as they are known,  
could become a thing of the past thanks to a new technology that will help  
ensure electronic devices keep getting smaller and more powerful. 
A consortium led by the Technical University of Berlin has developed a  
commercially viable technique to embed active chips in Printed Circuit Boards  
(PCBs), opening the door to a new generation of electronic devices that can pack  
more features and functionality into a smaller space. 
Size is not the only advantage, however. Embedded chips are also more robust  
and reliable, have better radio frequency properties and displace heat more  
readily than their packaged counterparts. 
“Packaged chips, the things that look like black plastic beetles on a circuit 
 board, are an obstacle to further miniaturisation of devices such as mobile  
phones and PDAs,” explains Andreas Ostmann, a researcher at the Technical  
University of Berlin. “Several years ago we foresaw this problem facing the  
trend toward smaller, more compact and more reliable devices.” 
On sale within three years
That premonition led to the launch of the _Hiding Dies_ 
(http://www.hidingdies.net/)   project, an EU-funded initiative coordinated by Ostmann and 
involving commercial  partners such as Phillips and Nokia, among others. Over three 
and a half years,  the team developed and tested a method to embed chips in 
PCBs, creating  components that are not only remarkably small but also relatively 
cheap to  produce. The first products incorporating them are due to go on sale 
in less  than three years. 
“There are two ways to use the Hiding Dies technique: you can create chips  
that are integrated into the PCB or modular Systems in a Package (SIPs) in 
which  each integrated chip has a specific functionality,” Ostmann says. 
The microchips are around 50 micrometers thick, roughly the same width as a  
human hair, while the smallest module produced with the Hiding Dies technology 
 is around 100 micrometers. That compares with the minimum of 500 micrometers 
for  current chip packages. 
Their small size allows them to be stacked to pack more performance into  
devices without taking up more space, a form of 3D integration that is virtually  
impossible with packaged chips, while their close proximity to each other 
does  away with long interconnects. 
“Because the chips can be placed side by side inside the polymer of the board 
 the interconnects are much shorter and their radio frequency properties are  
greatly enhanced. This is important as modern devices are operating at higher 
 and higher frequencies,” Ostmann explains. 
Size is not the only asset
One spin-off from the Hiding Dies project has  been an initiative to use the 
embedded chips in a radar safety system in  vehicles. The system, a kind of 
adaptive cruise control that keeps cars a safe  distance apart, operates at 77 
gigahertz, well above the frequencies used in  most current wireless devices. 
The auto industry is one major, if unlikely, market for the embedded chips,  
not so much because of their small size but because of their reliability and  
robustness. In the harsh environment of a car, the long interconnects and  
soldering on packaged chips can be worn down by heat fluctuations and  
vibrations, eventually causing them to break and the chip and whatever function  it 
performed to fail. However, by sandwiching the chips inside the PCB they –  and 
the interconnects around them – are much better protected. 
“We’ve done heat tests and the chips passed without a problem,” Ostmann 
says.  The partners also performed drop tests – a common occurrence with mobile 
phones  – and devices continued to function. 
In fact, Ostmann foresees the chips being incorporated into a broad variety  
of everyday devices, from TVs and stereo systems to air-conditioning units and 
 kitchen appliances. “These chips could be used for smart power control to 
make  devices use electricity more efficiently,” Ostmann says. “For that, they 
are a  cost-effective solution compared to current techniques.” 
One project partner, AT&S, Europe’s largest PCB manufacturer, has already  
carried out several customer evaluations and is looking to start incorporating  
the chips into products in 2009. 
“Consumers initially probably won’t see much difference. The technology is  
deep inside. However, in the long run these chips will allow devices to become 
 smaller, more powerful and more robust,” Ostmann says.
Source: ICT  Results





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