Intel's 45nm CMOS Technology

  Section 4 of 12  

45nm Design for Manufacturing

CO-OPTIMIZATION

Lithography, optical proximity correction process, and design requirements all need to be understood in defining a new technology. Co-optimization to balance requirements for all of these areas is needed to define a very manufacturable process and design. The different needs of each area must be balanced in the context of different constraints. The design groups want small die size for low cost, but they also want design work to be easy. Flexible design rules are needed to allow designers to optimize the product with minimum effort and area. Lithography engineers also want simple design rules but cannot allow unlimited flexibility. OPC engineers want layout to be very predictable so there are no hotspots that are caused by the use of unexpected combinations of rules. In the definition process, all of these different goals are considered to find an acceptable solution. The ability to consider all aspects of the problem from design to high-volume manufacturing, within an affordable envelope of multi-dimensional constraints, is the key to good DFM solutions.

Co-optimization is done from the beginning with a multi-disciplinary team that includes experts in design, lithography, OPC, and processing. We have design experts in the process development organization who closely interact with the process development engineers, and we also include representatives from the lead product designs and CAD tools' engineers in the definition process. The discussions between these experts start about four years before the technology begins production. There was a significant increase in the co-optimization work for the 45nm technology. More layout studies were done early in the definition process, and there was an increase in the modeling of design rules.

The goal of co-optimization is balancing the risk and difficulty between design and manufacturing. It may appear to designers that our solutions are not balanced, since design is more difficult on each new process. The reality is that the process and patterning choices are often limited. The lack of improvement in resolution of the lithography tools limits patterning options. DFM definition often has to make the choice that will have the least impact upon design. A solution with no impact is not possible, however. The need for low costs may result in changes in design rules for smaller die size or better yields to offset concerns about increased design effort. Judgment about manufacturability will take priority over concerns about increased work for designers.

  Section 4 of 12  

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