Milkyway Library
Milkyway is a Synopsys library format that stores all of circuit files from synthesis through place and route all
the way to signoff. Most Synopsys tools can read and write in the Milkyway format including Design Compiler,
IC Complier, StarRCXT, Hercules, Jupiter & Prime Time
The Milkyway database consists of libraries that contain informa on about your design. Libraries contain
informa on about design cells, std cells, macro cells and so on. They contain physical descripons and also
logical information
Milkyway provides 2 types of libraries that we can use (i) reference lib and (ii) design lib. Ref lib contains std cells and hard (or) so macro cells which are typically created by vendors. Ref lib contains physical info such as routing directions and the placement unit le dimensions which is the width & height of the smallest instance that can be placed. A design lib contains a design cell which contains reference to multiple reference libraries (std cells & macro cells).
The most commonly used Milkyway views are CEL & FRAM. CEL is the full layout view and FRAM is the
abstract view for place and route operations.
FRAM view:
Synopsys tool IC Complier use “FRAM” view as PnR abstract. FRAM view is a cell view that has only the PINs and metal and via blockages defined.
This makes sure that the interconnection on between the PINs can be routed automatically and that the routing tool will not route over existing metal/via areas thus ruling out any shorts.
Cadence EDI tools use LEF views which again has only the PINs and blockages defined