Issue link: https://iconnect007.uberflip.com/i/490885
18 The PCB Magazine • April 2015 anylayer microvia boards yield improvement is essential due to long manufacturing process and fine feature sizes, so breakeven point can be reached. Leading edge smartphone boards have become difficult to produce without LDI. It offers significant benefit allowing individual scaling for panels reduction of the alignment related yield losses. In order to get the full benefit of LDI the dry - film and/or wet resist has to be matched with imaging technology for optimized yield. Re- cently there has also been significant improve- ment in the resist capability and productability. That might help to make the investment for LDI imaging process as there will always be a desire to use tried and tested technology when faced with a choice of some other, perhaps slower, more expensive, more problematic al- ternative. And still approximately 25% of new LDIs sold are used to image solder mask. DI in this particular application has the potential to bring enormous yield rewards, but is hampered by much lower throughput [6] . II. Summary A closer look at key ALV HDI manufactur- ing processes and their impact on cost and tech- nology benefits has to be taken in account when selecting the optimized process, and therefore, a major opportunity to meet the current and future needs of electronics packag- ing must be considered. The functionality in- crease and size reduction are not the only chal- lenges for HDI PCBs. The increasing operating frequencies with ultrathin constructions will play a more important role in near future end products. The role of the effective supply chain management is essential to have the materi- als and manufacturing solution ready on time. As minimized prototype cycles result in faster product launch in the market place. Subtractive process (foil or plating) ultimate- ly faces limitations of nominal thickness and thickness variation and is sensitive to conduc- tor spacing, thickness variation, and base foil roughness. Additive processes have fundamen- tally higher system resolution and superior con- ductor geometry but are complex to engineer/ control and might require capital investments. The conductor geometry of mSAP has superior signal integrity with lower loss and crosstalk due to straight sidewalls. There is no easy answer for manufacturing process selection as it depends on the product design features. Early involvement in design process is helpful for finding the most cost ef- fective solution. PCB Acknowledgment The authors would like to thank Chris Katz- ko for his timely support and contribution. This paper was originally presented at the 2014 Electronic Circuits World Convention. References 1. Joachim N. Burghartz, Editor, "Ultra-thin Chip Technology and Applications," Institut fur Mikroelektronik Stuttgart (IMS CHIPS) Allman- dring 30a, Germany, pp. 17, April 201. 2. Erkko Helminen, Tarja Rapala-Virtanen, "Miniaturization Influence on Electrical Func- tionality of High Density Printed Circuit Board" 'in press' ECWC13, 2014. 3. International Data Corporation (IDC), Worldwide Quarterly Smart Connected Device Tracker, 2013-Q3 edition, 2013 September 11; Smart Connected Device Market by Product Category. 4. T. Katahira, J. Scanlan, J. W. Park, K.S. Oh, "0.3 mm Pitch CSP/BGA Development for Mobile Terminals," International Micro- electronics and Packaging Society, IMAPS, November 11–15, 2007, San Jose, CA, USA, pp. 393–401. 5. Stephan Kunz, Schmoll-Maschinen GmbH, EIPC Winter Conference Geneva, Swit- zerland, January 30 & 31, 2014. 6. JPCA 2014 Show Technology Summary. Tarja rapala-Virtanen is in technology at TTM Technologies Inc., asia Pacific, China. erkko Helminen and Timo Jokela* are in technology/r&D with TTM Technologies Inc., asia Pacific, China/Finland* NExT-GENERATION ULTRA-THIN HDI PCB MANUFACTURING CHALLENGES continues FeAture