Virtual versus Vertical

Both ASIC and COT designs need the designer to fix the foundry at the onset. This is because the library and the design rules needed for both are supplied by the target foundry. COT, however, does have the flexibility for changing the foundry at a later stage provided the process is compatible across multiple foundries – however it still needs some verification to avoid problems on silicon. Multiple sources especially where one needs backups and also an advantage for price negotiations have been in the picture.

DFM does change a lot of value propositions. COT’s have been less costly not just because foundries compete on price but also because the extra service of design implementation in an ASIC comes with it’s own price tag. With DFM, the boundary between design and manufacturing is getting blurred and hence not many will opt for the traditional COT approach. Foundries will (and are) moving up in the design value chain.

With DFM, there is an increased need for foundries to share process information so that it’s taken into account during the design phase. Foundries collaborating with EDA vendors for this result into tools handling the yield issues while making it as transparent to the designer as possible. Design flows were devised and verified with specific tools (from single or multiple EDA vendors/sources) to tackle various design issues and facilitate FTSS. Now the verification of these flows includes another variable – foundry. i.e. a designer will need to know which foundry’s data has been used to verify the design flow before he starts using it.

Going to the next technology node has had a triple advantage – reduced power, higher speed and reduced cost due to lower die size. But as we go from 90nm to 65nm and further below, this shrink is leading to only a speed advantage. Leakage, signal integrity & yield issues have reduced the other two advantages. So, we’ll see lesser designs migrating to or starting up in these new technos. And this is besides the high costs involved (for design, mask etc.). Foundries like TSMC are spending a lot of money to build new fabs to handle these advanced nodes’ designs. So, after having invested a fortune, they can not let them be empty. There will be an economical need for them to see their foundries operate at capacity. For this, they will need to facilitate new designs in these technos; and hence they will be compelled to either share more information/collaborate or do every thing on it’s own i.e. a one stop shop.