Buried parts are finding homes in everything from handhelds to servers and ATE gear.

Embedded 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 co-fired 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 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 shipping a power management module with an embedded IC in a WLP in its wristwatch for more than a year.

Digital tuners for mobile TV broadcasts represent a major growth area for embedded actives. Companies that make TV tuners include Alps, Mitsumi, Murata, Panasonic, Sharp and Sony. The goal is to make the tuners smaller, thinner and reduce power consumption; embeddeds are an increasingly popular way to achieve this goal.

Some SAW duplexers contain embedded ICs. Several companies, including Renesas, are considering use of an embedded logic device in the bottom package of the PoP.

Taiyo Yuden is shipping a DC-DC converter containing embedded components in a laminate substrate. DNP ships millions of modules per month containing embedded passives, and the company is starting to ship embedded actives. Camera modules are one of the largest volume applications.

Laminates are not the only substrate option. Interest is increasing in thin-film substrates with embedded passives. Technologies from NXP and STMicroelectronics are in mass production in high volumes. Murata owns SyChip, and its technology is expected to see greater adoption. Subcontractors such as STATSChipPAC have also entered the field.

Adoption concerns. Adoption of embedded components still raises some concerns. For many semiconductor makers, a substrate partner is key to successful commercialization. Embedding devices requires the substrate maker to embed components – requiring capital investment and implementation cost. Super-thin parts are required for embedding, and with die thinning comes handling and dicing issues, as well as concerns over post-lamination reliability. While embedding an active die in the form of a WLP is one solution to the known good die problem, there are still concerns about how to inspect and test the module or board after embedding. Concerns about cost also remain. However, much progress has occurred. While the typical assembly equipment does not support board thickness or work panel size, new equipment is being introduced. A number of organizations are working on issues. Casio now has 26 members in its embedded WLP consortium, including substrate makers, module users, and device makers. A number of companies are readying product introductions, and a variety of applications are expected during the next few years.

E. Jan Vardaman is president of TechSearch International (techsearchinc.com); jan@techsearchinc.com. Her column appears bimonthly.