1、,Are There Economic Benefits in DFM ? - a Fabless Design House Perspective -Riko Radojcic Matt Nowak,What IS DFM to Qualcomm ?,DFM = everything that a designer can do to ensure that the product meets its performance, power and cost targets Tight design to process coupling for : Litho effects = to ge
2、t what you see in x-y plane CMP effects = to get what you see in z-plane Variability = to get what you simulate electrically Random effects = to get the yield that you modeled Act of God effects = to get the operating margins you need,DFM = everything that the foundry partner tells you to do ? DFM =
3、 everything that the EDA supplier says you can do ? DFM = everything that the DFM Start Ups say you should do ? DFM = everything that the designer thinks he should do ? DFM = business as before and hope for the best ?,So . ?,What is the Big Deal about DFM ?,Process windows are getting awfully tight
4、Ergo, need to tighten up the design : as always !,QUALCOMM Perspective,Why go to next generation of Technology ?,Higher Performance New features Cut-over as soon as possible Allow for de-bug, system integration Yield is Boss ! DFM very important,Lower Cost Existing (mostly) features Cut-over when co
5、st is better Allow for system re-qual time Die Size is Boss ! DFM desirable & optional,DFM seems to be the right thing to do, but Does it really make money for a Fabless COT House?,So, ARE there Economic Benefits in DFM ?,Dont Really Know : The commercial DFM space is fuzzy and confusing The economi
6、c value of a DFM technology is confusing The business case for DFM is unclear The relative benefit of a DFM methodology is unclear What we do know : DFM is done to Optimize Costs and is hence a Business Decision Any designer should be able to deal with the DFM trade offs,Need to Segment DFM Universe
7、,Segregate DFM activities into 4 types,Qualcomm has a different role with each bucket,Qualcomm role is that of a champion or a promoter Principal differentiator is accuracy.,Qualcomm role is that of a client Principal differentiator is use mode and integration.,For this segment need a 3 way relation
8、ship,Need to Monetize DFM Technical Value,DFM Design Decisions,Process Design Kit,EDA Tools,DFM is Design to Optimize vs. Pass Go-No Go Checks Function of process characteristics and maturity Function of design technology and trade off vs. other variables Function of product volume and ASP ramp,Need
9、 a DFM Business Case,Business Model for Sharing Costs and Benefits Foundry should reap the benefits for process improvements Fabless design house should reap some benefit for DFM improvements,Wafer Business,Die Business,Foundry,Fabless,The incremental COST of DFM is mostly on the Fabless side not en
10、tirely: foundry does more characterization,With Wafer Business the BENEFITS are mostly with Fabless side not entirely: foundry gets larger virtual capacity,With Die Business BENEFITS are mostly on the Foundry side not entirely fabless gets larger capacity,The challenge is a Business Case for DFM in
11、a Fabless House using a Die Priced Business Mode,1,2,3,4,Need a Metric for DFM Benefits,Yield or Project Cost is too Complicated Retroactive direct measurements Many compounding and confounding factors Feedback loops long & often cloaked in economic factors Need some Relative DFM “Score” Arbitrary n
12、ormalized number Simple and non controversial Not necessarily a direct measures of yield or cost but intuitively related to those Usable without a dedicated process-specific test chip Perhaps Use Separate Scores, as makes sense ? e.g. systematic vs. random vs. parametric phenomena,In fact Need Two D
13、FM Metrics,Match 2 kinds of costs “Cost of Design” measure the efficiency of implementing a given DFM optimization at various steps in the design flow e.g. routing, or (expensive) polishing, or (more expensive) OPC/RET “Cost of Si” measure the net effectiveness of a given DFM optimization e.g. perce
14、ntage of redundant vias,Being a high volume shop, these are the key metrics that Qualcomm is very sensitive to,These metrics are important to Qualcomm but will not make or break a product,DFM Metrics for Cost of Design ?,e.g. frequency of occurrence of undesirable constructs ? Bucketed in groups and
15、 Weighted by : Dimensions (e.g. at Design Rule vs. at DFM Guideline) Phenomenon (e.g. OPC unfriendly jog vs. notch vs. . )Or something like this ?,Even un-weighted numbers would be useful as it would allow comparing a design before and after some DFM transformation,DFM Metrics for Cost of Si ?,e.g.
16、frequency of occurrence of given features Bucketed in groups and Weighted by : Phenomenon (e.g. via vs. CA vs. ) Layout configuration (e.g. bordered vs. borderless via)Or something like this ?,Even un-weighted numbers would be useful as it would allow comparing a design before and after some DFM tra
17、nsformation,So, ARE there Economic Benefits in DFM ?,Cant Really Know and will not know until : The DFM buzz is clarified Need a clear definition of client-supplier relationships Tool ROI is clarified Need a way of estimating the benefits DFM cost vs. benefit is clarified Need ability to simulate and share benefit vs. time Process data and ownership is clarified Need standard Design Kits What we do know : We need DFM Score metrics We need Process Design Kits,
