Circuits Assembly - March 2008 - (Page 22)

On the Forefront Embedded Components Get Real Buried parts are finding homes in everything from handhelds to servers and ATE gear. mbedded components – actives and passives – are receiving increased attention at trade shows and seminars worldwide. Indeed, it was one of the hot topics at the Tokyo-based InterNepcon show in late January. Advantages of embedded components include reduced size and weight, including smaller footprint, reduction in board thickness and fewer components. Embedding components frees space for additional parts within the same footprint and, in some cases, the subsequent elimination of SMT vias improves signal routing, the result of a shorter electrical path. For some structures, solder can be eliminated or reduced, resulting in a “green” product introduction. At the system level, placement cost is lower and inventory handling of formed components reduced. Embeddeds are not a new topic. Multilayer cofired ceramic technology has been used in electronics since the 1950s. The ability to embed passives in high- and low-temperature co-fired ceramic (HTCC/LTCC) substrates made multilayer ceramic technology an attractive option for computer, automotive, wireless and other applications. LTCC became popular in the 1990s for RF and wireless applications. Many early Bluetooth devices were fabricated in LTCC because the large number of passives required for the RF circuit could be embedded within the LTCC layers to reduce size, weight and cost. The technology to embed resistors and capacitors has been in use for more than 20 years. Applications, materials and processes to embed both actives and passives are new. Today’s primary applications using embedded resistors are defense/aerospace, network infrastructure and mobile communications. While several core defense and aerospace contractors have used the technology for years, a number of new companies have recently decided to shift to embedded resistors to resolve weight and reliability concerns. Network infrastructure applications such as switches are also a major adopter. Embedded capacitor applications include high-end servers, network infrastructure systems, data storage networks and ATE systems. Emerging applications include mobility devices such as GPS and base stations, as well as medical and military. Approximately 40 PCB fabricators offer embedded component technology, and the number is expected to increase. Mobile communication devices are one of the major products driving adoption of embedded E Figure 1. TCR resistors comprised of a resistive layer deposited onto Grade 3 ED copper foil in a proprietary roll-to-roll, vacuum metallization process (source: Ticer Technologies). E. Jan Vardaman is president of TechSearch International (techsearchinc.com); jan@techsearchinc. com. Her column appears bimonthly. Figure 2. Pull up/pull down embedded resistors (source: Ohmega Technologies). actives. The trend in mobile phone handsets continues to be smaller form factor with increased functionality. Embedded actives are used in several configurations. Some companies embed actives in the form of a flip-chip device or a wafer-level package on an innerlayer of the IC package or module substrate using a lamination process. For years, RF devices such as Bluetooth have been embedded, beginning with applications in PCBs for mobile phones. In Japan, Clover reports shipping more than one million embedded ICs with flip-chips in its cellphone boards since 2003. Casio has been circuitsassembly.com 22 Circuits Assembly MARCH 2008 http://techsearchinc.com http://circuitsassembly.com

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Circuits Assembly - March 2008 Caveat Lector Letters Industry News Market Watch Talking Heads Focus on Business On the Forefront Screen Printing What Drives the Crowd? Mastering ESD Control in Automated Handling Systems Beating the RoHS Heat Trade Secrets True to Its Roots The Road Abroad - Strategic Alliance or Greenfield Facility? Tech Tips Wave Soldering Test and Inspection Process Doctor Pb-Free Lessons Learned Getting Lean Materials World Equipment Advances Apex Product Preview Ad Index Assembly Insider Technical Abstracts

Circuits Assembly - March 2008

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