2.5/3D Packaging: Path Finding

2.5D/3D packaging technologies are revitalizing creativity in high technology products. We thought we knew what faster, better, lighter and smaller meant. 2.5D/3D packaging can revolutionize what we thought possible but it will require augmenting our current methods and tools. One key methodology to add would be Path Finding. Path Finding can ensure a design’s structural integrity early in the development process and avoids finding issues that
may be identified when it is too late to fix cheaply and quickly.

Path Finding tools allow designers to create a virtual prototype for a design’s physical structure. Path Finding tools can be applied to three failure mechanisms: mechanical (stress), thermal (heat) and electrical (power distribution, signal integrity) concerns and can include cost estimates as well. Each of these mechanisms must be accounted for in the physical structure of the design. To be useful, Path Finding tools must be used EARLY in the planning phase. Using a “post” implementation mentality similar to what is performed for Physical Verification (PV) is too late for these structural issues. Path Finding will never replace PV. Path Finding helps define how something should be implemented most reliable and cost-effective; this does not guarantee that the definition was implemented correctly.

This white paper, authored by Bill Martin, of E-Systems Design, discusses the importance of Path Finding in design of 2.5D and 3D packages. It explains the advantages chip and system designers gain by using path finding tools, and provides examples of path finding tools implemented in designing silicon interposers with TSVs. It is the first in a series on this topic.

(Republished with permission from the authors. This was article originally published in December, 2013 by the Global Semiconductor Association (GSA) in the March 2013 issue of GSA Forum.)