Herb, it looks like the momentum we expected has not yet materialized. Without a lower cost manufacturing alternative, 3D stacks will remain a play for bigger companies with the purse to fund the projects and more agile smaller players will be left out. Your line "how many IC designers were in the audience..." says a lot about the status of design engineers embracing and realizing the potential to develop products in 3D.
MP, Thanks for your frequent comments! My primary concern is that the packaging experts can only compare COMPONENT cost of 2.5/3D-ICs versus the traditional, and until now save approach of following Moore's Law. That's why we are stuck at this "cost problem".
In my 20+ years in the ASIC business I saw the real breakthrough of ASICs when 1) system designers realized the opportunity of increasing system speed, lowering power and boardspace and 2) worked, together with their IC designers and the ASIC design center engineers on re-architecting their systems and 3) last, but not least, convinced management to approve significant budgets to pay ASIC NREs.
As an eternal optimist, I am continuing to encourage our industry's decision makers to recall their experience with the transition from 7400 logic to ASICs and make the right decision again.
In a mega-panel moderated by Matt Nowak, a 3D stacking expert at Qualcomm, more than a dozen experts discussed a few technical and many business challenges related to interposers. They concluded the technology is ready but we need lower costs.
But here's the thing. If the technolgy is too expensive, it doesn't strike me as technology being ready. What needs to be done to lower cost?
It is nice to learn technology is ready and looking for lower cost for manufacturing. Is tihs porper time to test and qualify its quality and reliability so that they can be employed in value added items with high reliability requirement.
Since there is evolutionary change in process technology, it will take time to prove its reliability.
Cost is an excuse; thermal is the key problem so we can't stack two hot processors. By stacking DRAM on heat-sinked logic, maybe the DRAMs just warm up a little. Otherwise, just 2.5D can be expensive, but that's not a stopper.
There's a saying on Wall Street I think applies here;
"Those who know don't say, and those who say don't know."
TSV technology has been used for a while now, even down into commodity class consumer items. The answer to cost depends upon who you ask.
There's several high margin applications using DRAM that will begin the cost decline curve. Introduction of "cognitive computing intelligence and predictive analytics" machines is dawning - some say it is the next computer evolution - it requires novel and innovative use of memory to make responsive.
Slow motion development of 450mm and EUV is fanning the need for "micro-vertilization" of the volumetric foot-print.
Some manufacturers have learned how to stack devices, some have patents on using graphene heat spreaders. Like all things new, learning the trade will require time...,
Hi Junko, great to hear from you - it's MANY years since we discussed settop boxes at VLSI, together with Tim Vehling.
You are right: If the first impression is "too expensive", it can quickly turn off customers.
To answer your question "what can be done to lower cost, allow me to put COMPONENT COST into a larger context:
Component cost is rarely the only factor determinining the final decision of a technology user. Cost savings on the system-level and/or higher selling price of the system -- because of longer battery life, higher performance,lower cooling cost, smaller formfactor, lower development cost, shorter development time, etc --- can compensate in many applications the higher cost of component.
I also see RE-USABILITY becoming a decision criteria already, in favor of designs using interposers or 3D vertical stacking of die. As design teams work really had to migrate 28 nm SoCs to 16/14 nm FinFET process technology, they express serious worries about how much time and money it may take to migrate these designs to the next node, e.g. 10 nm!
Interposers and vertical die-stacking introduce us to DIE-level modularity and re-use. Just like the emergence of soft- and hard IP started to change SoC design at the end of the last millenium, this modularity will significantly impact SoC AND system design in this millenium, actually in this decade already.
And, in addition to these strategic considerations, equipment vendors, material suppliers, packaging- and test experts and others are continuing to work hard to reduce component input cost, increase throughput (units/hour) and manufactuting yields.
Let's not forget what we experienced with every new technology: Economies of scale further reduce unit cost.