Embedding capacitors and resistors into printed circuit boards using a sequential lamination technique

Embedding capacitors and resistors into printed circuit boards (PCBs) offers many benefits over surface mount technology (SMT) and through-hole packaging (PTH). These benefits include improvements in electrical performance and reliability, and potential cost reduction. Embedded devices also enable signal integrity at speeds over 1 GHz. Also, replacement of surface mounted discrete passives with an embedded passives layer allows for tighter component spacing, fewer holes and a larger routing area. All these are essential for board miniaturization. However, the goals of reliability improvement, space conservation, performance enhancement and solder joint reduction by using embedded passives can only be realized if the PCB fabricator can produce high quality boards in a practical production environment in a timely manner. This paper describes an investigation of the manufacturing of embedded resistors and capacitors on a prototype basis and the possibility of extending this technique to normal mass production. The proposed sequential lamination technique (SLT) was applied to form a PCB with embedded passives. Then, to verify the manufacturing capability, samples of integrated planar resistors and buried capacitors were fabricated on specially designed PCB test panels. The component readings are also presented in this paper.