Printed Circuit Design & Fab - November 2007 - (Page 26)

HDI DESIGN AND FAB density (typically, A=1 for ASICs) and provided in EQUATION 2 as: FPY Percentage (%) = 100 Exp{[(log CI)/A]B} Where: FPY = first-pass yield CI = complexity index A, B = Fabrication Capability Coefficients To determine the constants A and B in Equation 2, a fabricator must characterize his manufacturing process by selecting a number of printed circuits currently being produced (TABLE 2a) and having various complexity indexes, hopefully some low, medium and high. The first-pass yield (at electrical test without repair) of these printed circuits for several production runs is recorded (TABLE 2b). A statistical software program, such as Microsoft Excel, that has a model-based regression analysis is then employed to determine the FCC constants A and B, from this model, for the particular fabricator (TABLE 2c). Constant A determines the slope at the inflection of the yield curve, and constant B determines the X-axis location of the inflection (TABLE 2d). The confidence level in yield predictability is determined by the statistical margin of error in the calculation of A and B. Now Available! Printed Circuit Board Basics • 81 pages • ISBN 0-9743561-0-7 Conclusion The results in Table 1 show the improvements that blind and buried vias provide in layer and size reduction. The relative costs are taken from Table 1 by multiplying the RCI by the board size. Also important is the reduction in drilled holes since this is a major influence on the complexity index and FPY. When the relative costs are divided by FPY, the results are seen in Table 3. The more complex HDI via structures enable smaller boards with fewer layers and fewer drilled holes. TV1 has a 29.3% savings over the through-hole version, but TV2 is a 49.1% reduction; TV3 is a 58.0% reduction; and TV4 is the largest with a 62.9% reduction in cost. What isn’t taken into account here is the improvement in reliability that fewer through holes with a lower aspect ratio (due to thinner boards) provide. Microvias with their extremely low aspect ratio (AR < 1.0) are shown to be many times more reliable than through holes. PCD&F The fourth edition of Printed Circuit Board Basics: An Introduction to the PCB Industry by Dan Beaulieu ONLY $34.95 Order your copy of PCB Basics today! Finally there’s an easy-to-read handbook that explains the process and business of printed circuit board manufacturing in simple terms that anyone can understand! A must-read for those who are new to the industry and a valuable resource for those who work in the industry, Printed Circuit Board Basics: An Introduction to the PCB Industry is the perfect book to help your customers and employees understand the services your company provides to the PCB industry. Authored by Dan Beaulieu, a 30-year industry veteran and a founding partner of D.B. Management Group, and edited by Mike Buetow, editor-in-chief of Printed Circuit Design & Manufacture magazine, the fourth edition of Printed Circuit Board Basics contains: • An updated primer on single-sided, double-sided and multilayer PCB manufacturing processes; • A review of new technologies such as embedded components and microvias (HDI); • Updated PCB specifications; • A history of the industry; • Detailed, updated graphics – including over 45 color photos and illustrations; • An updated glossary of terms and definitions (twice the size of the glossary in previous editions); • And much more! REFERENCES 1. Printed Circuit Handbook 5th Edition, Coombs, McGraw-Hill, 2001, pp. 1.5 2. Printed Circuit Handbook 6th Edition, Coombs, McGraw-Hill, 2007, pp. 23.2 3. “Calculate Your Fabrication Capability Coefficient, Happy Thoughts, CircuiTree, Feb ” 15, 2006, BNP pp. 23.5 , 4. “The Need For Statistical Tools, Happy ” Thoughts, CircuiTree, Oct. 15, 2002, BNP , pp. 23.5 Order your copy of Printed Circuit Board Basics today for only $34.95 plus shipping and handling! To order, visit: pcdandf.com/cms/basics 26 HAPPY HOLDEN is a senior technologist with Mentor Graphics. He can be reached at happy_holden@mentor.com. NOVEMBER 2007 PRINTED CIRCUIT DESIGN & FAB http://pcdandf.com/cms/basics

Table of Contents Feed for the Digital Edition of Printed Circuit Design & Fab - November 2007

Printed Circuit Design & Fab - November 2007 Contents Our Line Market Watch Around the World Happenings ROI Packaging HDI Design and Fab Plating Design Tools Metric Design Productronica Product Preview Marketplace Ad Index The Signal Doctor

Printed Circuit Design & Fab - November 2007

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.