CircuiTree - September 2008 - (Page 44)

coordinate package design and chip design. As chip complexity and package complexity grew, these methods became too cumbersome: Excel spreadsheet ﬁles several hundred MB large turned the process into an obstacle rather than an aid. industry integration standards, the tools still work together. The codesign tools act as the glue or integration provider between the EDA environments for chip, package, and PCB. Organizational Convergence In a design ﬂow such as the one described previously, the boundaries between chip design, package design, and PCB design become fuzzy. Each designer needs to have some understanding of the other two disciplines. In the traditional ﬂow, there are often brick walls between the groups, while in the modern co-design ﬂow, the design effort becomes one of constant collaboration where solutions to design issues often require arbitration between all disciplines. This challenges the traditional organization: who should be responsible for each part and who is responsible for the complete system? Who should have the authority to drive a change of a chip I/O conﬁguration? These are very important questions. As a system has to be codesigned, it’s no good if the package engineer can’t be allowed to impact the chip design and equally bad if the PCB designer isn’t allowed to impact the package design. On the other hand, the chip designer has chip design knowledge the package engineer lacks, so the I/O changes proposed may not make sense to the chip designer or even appear risky or destructive. It is easy to see how the traditional organization has conﬂicts of who is in charge, as each team is measured on its respective piece. The solution is to let the design teams converge toward a system group with a common manager owning all three disciplines and, more importantly, where the success of the designed system is used as a measure of the entire team. Figure 1 Huge Excel Spreadsheets Were Used to Bridge the Gap Between Chip and Package Design Still Failing to Cover the PCB Side of the Equation Design tools that bridge chip design, package design, and PCB design are now needed to manage the process. While chip-package codesign tools for single chip packages have existed for some time, what is needed here is a tool that also spans into co-designing the PCB and that supports multichip packages such as SiP or SoP, and even PoP. Figure 2 shows such a tool where chip, package, and board interconnects are part of the optimization process. Conclusion So, has package and PCB converged? There is clearly both a technology and a methodology convergence and successful corporations are building cross discipline organizations. PCB design, when driven by strong market drivers, will undertake advanced packaging technology to increase density and performance. There is just no other way to go. In some cases the package is bypassed or merged with the PCB, making the PCB a form of super package. As the consumer market continues to drive technology, we will see a continued development and use of advanced board substrates. The same is true for package technology, so will the two ever completely converge? (Or merge?) It’s hard to make predictions, especially predictions about the future, but it seems as there will continue for the foreseeable future to be a need to have boards and packages separate. The technology to completely merge the two clearly exists but the market demands are such that the ﬂexibility of keeping package and PCB still wins. New tools are available to help manage the chip-package-PCB design space and to help bridge the knowledge gaps to avoid stretching designers too thin. We also see organizational changes applied as a means to allow (maybe force?) chip, package, and PCB designers to cooperate as a team to design modern, high-performance, multi-technology systems. Converged indeed! ■ Per Viklund is director of IC Packaging & RF, Mentor Graphics, Systems Design Division. Email: per_viklund@mentor.com Figure 2 Chip-Package-PCB Co-Design Takes Both Chip-Package and PCB Into Account to Calculate an Optimal Solution These tools have the ability to support the design process extremely early in the design ﬂow and let each team supply its data and run various what-if scenarios in a virtual prototyping ﬂow before actual design data is available. Chip, package, and PCB are separate domains and design teams need to pick the tool that is best suited for each discipline rather than a single vendor. Consequently, we often see chip design teams using a mix of tools from all the major suppliers. Using 44 September 2008 • circuitree.com http://circuitree.com

Table of Contents Feed for the Digital Edition of CircuiTree - September 2008

CircuiTree - September 2008 Contents My Line Industry Review Tech Talk Flexible Thinking New Halogen-Free Materials: Their Time Has Finally Arrived Asian Section IPC Issues PCB and Package Convergence Ask the Flexperts Market Outlook IPCA Showcase Technical Product Spotlights Classified Ads Upcoming Events Ad Index

CircuiTree - September 2008

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