Dealing with silicon-package interactions

by Bob Haavind, Editorial Director, Solid State Technology

Chip design, foundry/fab, and packaging partners must work in concert to reduce risk on new technology offerings, according to Mike Barrow, SVP, flip chip technologies, Amkor, at the ConFab packaging panel session called “Think Outside the Fab.” Packaging technologies are about to explode on us, he believes, as a daunting number of new packaging options will become available over the next few months.

By giving the packaging group early access to advanced silicon, chip and package interaction (CPI) solutions can be achieved that are market-ready upon silicon node release, according to Barrow. He pointed out that package and laminate design are in the critical path, and need to be co-designed with the silicon to deliver cost-effective solutions.

Barrow went into some detail on the package-silicon interactions. For example, low-k material interface adhesion and stresses must be dealt with collaboratively early in the technology design phase. It is also important for new foundry/package materials and process developments to be worked on in parallel, not serially, to keep the project moving forward.

Chip and package interactions are very complex, as Barrow illustrated with a case in which there was electrical pass after assembly even though delamination of metal and the interlayer dielectric (ILD) was found. To co-design the package and laminate along with the silicon, a complete suite of design services should be available prior to tape-out, he said, to enable a more robust solution as margins shrink. Market success, Barrow emphasized, depends on optimizing silicon, mask, and package revisions.

He illustrated parallel design paths (see Figure) that will help decrease time-to-market. During package selection, including bump/ball distribution and layer assignments, package routing can be designed. This can be followed by power grid analysis and confirmation of electrical performance. The pre-defined IP layout must be checked for timing data and connectivity, and thermal performance must be checked. The finished package must pass thermal and mechanical evaluation, and mechanical performance must be confirmed.

Barrow also showed an illustration of a complete package portfolio to provide the best fit to application and cost, supported by turnkey packaging capabilities, which he said can enable a system solution. Another important factor, he suggested, is defining clear ownership in each stage of the supply chain for issue resolution. — B.H.


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