Many readers may be unaware of a new standard coming out of Si2’s DFM Coalition early next year — one that I have yet to mention before now, but one that has significant potential benefits across the supply chain. So, I will use this blog to introduce OPEX — the Open Parameters for EXtraction. Someone suggested OPEX could also be an acronym for ‘OPerational EXcellence’, and here’s why.
OPEX was created to address the growing risk that has already cost the industry in terms of failing chips, with multi-million dollar price tags, and even worse a significant impact on tape out schedules due to re-spins. The root problems include:
1. the inability to confirm the validity of process parameter changes and ECOs across disparate design teams scattered around the world, across varying design flows using different tools;
2. the inability to confirm the validity of derived process parameter data against the master source data;
3. a lack of synchronization to changes in EDA vendor parasitic formats that are required to keep up with advancing foundry processes, making the mapping between the formats difficult and error prone (these commercial format changes may occur several times each year);
4. no existing semantic standard for naming conventions, ranges and units, or for process parameters or inter-parameter relationships, leading to more confusion;
5. errors existing in translation among parasitic formats and difficulty in managing the maintenance of various translators (which are often not lossless)
To manage these growing risks, companies have resorted to using multiple experts to review details of how to map process parameter names, units, ranges, and relationships, and maintaining wasteful conversion utilities and regression suites, and also hire consultants and perform business process audits to find, repair, and improve change procedures involved with process parameters after costly chip failures. It’s not a pretty picture.
The DFMC member companies have defined a solution to this problem with OPEX:
1. “Input Once, Use Many” — the master “Golden Source” process parameter data must be open, unambiguous, and comprehensive, easy to encrypt, track, control, distribute, and access across both commercial tools and in-house utilities, and easy to access / use over the internet (“in the cloud”).
2. “Golden Structure” for all process parameter data — based on XML with XSD structured templates, it can auto-verify compliance to naming, units, ranges, and relationships upon data entry or conversion.
3. Provably-Correct Export to SQL, UML, Excel — OPEX is more than a “file format”, it is an open XML/XSD database schema complete with verification routines and format translation support through integration with XML editors, SQLite databases, multiple scripting languages, and MS-Excel.
4. Data Visualization — Using 2D and 3D graphing features of Excel, process parameter data can be easily viewed to find corner cases that design teams wish to avoid that may affect performance or yield.
5. Ensure Interoperability — OPEX has been created to be fully compatible and bi-directionally lossless, based upon the generous contributions of ITF, ICT, and MIPT from EDA leaders Synopsys, Cadence, and Mentor Graphics, respectively. OPEX does not compete with any existing parasitic format, it complements them with an open, standard database and enhances their value with design teams. This is analogous with how the LEF/DEF format complements, but does not compete with, the OpenAccess database.
OPEX has already been used in its “pre-release” state by several DFMC members on production chips because it is so complementary, and has been verified as lossless alongside vendor formats. DFMC members are also working with the Synopsys IMTAB, which advises on changes to the ITF format, to keep everything in-sync. OPEX is really an open XML / XSD standard, with data populated and manipulated using SQLite, scripts, MS-Excel analysis, XML editors, and import/export with commercial EDA formats.
Solutions like OPEX have great practical value because they truly represent a huge potential for cost / time savings, and are entirely complementary with current practice. If you are interested in learning more about OPEX and how you can start putting it to use, please contact Si2 — or one of the OPEX WG members.