What does design for manfuacturing (DFM) mean to you? “More work to do!” “Someone else’s problem!” “Just more design constraints!” “The fab guys are expecting me to understand the process as well as design!”
I propose that we define DFM (design for mfg) as an attempt to trasfer a way of doing business that has been tried and tested in the manufacturing space for years, into the design space. The fabs have a long history of dealing with what I would call manufacturing for design (MFD). The basic mfg philosophy is that the only way we can ever hope to produce millions of chips from hundreds of designs with high yield is to measure, target and tighten variation in the manufacturing process.
For a fab guy everything begins with metrology (measure something). Someone once said that “You get what you measure.” They were right. With data you can understand the intrinsic distribution and ongoing trend that your process produces. Armed with data the fab tweeks the tools, flows, behaviors, etc. that tightens and centers the distribution and controls the trend over time.
I believe DFM can serve the same purpose in the design process. You will never improve the manufacturing robustness (quality) of you designs if you don’t measure something about the design that correlates to manufacturing robustness. With a good measurement in place it becomes a matter of tuning the design tools, flows, methods and behaviors to improve that metric.
I also don’t believe in the need to quantify the ultimate ROI before beginning this process. Measuring the quality of your design costs very little and understanding your own design quality variation will reveal low hanging ROI for improvement. The results of small initial steps will justify the next steps and so on and so on.
What do you think? Do you do DFM in your design flow? What kinds of things do you do? How did it get justified? Do you think it actually works?