Last week, Deca Technologies unstealthed. I found out through an article in the San Jose Mercury News. Deca is an independent subsidiary of Cypress Semiconductor. I zipped to the Deca Web site (once I located it), and found this quote by Cypress President and CEO TJ Rodgers from the Deca press release announcing the company’s coming-out party:
“Despite this breathtaking progress, there is an economic problem preventing the full integration promised by Moore’s Law: advanced semiconductor chips are becoming so specialized that they can’t be integrated into one chip. For example, due to process incompatibilities, there are no microprocessors available today with integrated DRAM. The process for one type of chip, for example, a 0.35-micron RF chip, may cost $0.02 per square millimeter—making it horribly uneconomical to integrate an RF block onto a microprocessor wafer costing $0.10 per square millimeter. Today’s systems contain very different chips made in different processes, in different fabs, and even in different countries. They therefore cannot be integrated on silicon and must be connected on PC boards, an ancient technology with 500-micron dimensions and a host of reliability problems.”
This is a precise and clear explanation and justification for interposer-based 2.5D IC assembly with the best, most concise economic explanation I’ve seen for selecting 2.5D assembly over monolithic ICs.
In fact, the press release drives this home with the two paragraphs that follow:
“We want to use the dense, reliable silicon interconnect inherent in Moore’s Law to integrate the dissimilar chips used in today’s systems, but we face an economic barrier because the interconnect on silicon chips is 1,000 times more expensive than the interconnect on PC boards.
“We could enable a new silicon-based interconnect paradigm if we could make silicon interconnect wafers for $10, just what silicon solar wafers cost today. The problem of mapping solar technology onto Moore’s Law is straightforward, but difficult, and we believe DecaTech has the answer.”
There you have it. Low-cost silicon interposer technology is Deca’s stated objective. This one’s worth watching.
EDA360 Insider 
Steve, I have been preaching this message that the industry will see many more 2.5D products before 3DIC starts to ship in large volumes. It is simply the physical/geometrical challenges of the PCB world which is stuck at 3mil/3mil pitch & line width rules for a number of years now (though there are some houses going smaller than this, as an exception to the rule).
Just curious on the cost metric -if a logic die costs $0.02 as compared to $0.10 for a RF die cited in the example, what is the cost target / range for the interposer normalized to mm^2? It would be interesting to know this metric…
Dr. MP Divakar