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This paper aims to explain how the goals have been met to manufacture rigid‐flex printed circuit boards (PCBs) in equipment used for rigid PCBs by utilizing new materials and process combinations.

A discussion of the technology and applications.

The main drivers for PCB technology have been size reduction, increased resolution, improved high frequency performance together with increased reliability and cost savings. To reach higher packaging density at the PCB level, Aspocomp has developed the technology with embedded active and passive components. However, in higher packaging density applications, the PCB‐technology has to offer more flexibility to PCB‐designers in order to effectively utilize space inside the electronic devices. Different flexible PCB solutions are needed to achieve this goal.

For fabricators of rigid PCBs there are challenges in production to adopt the new industry requirements.

This paper is of value to those involved with or interested in PCB technology.

Higher packaging densities for the next generation of electronic devices require utilization of the inner space of a PWB for component placement. This will shift some added value assembly processes from the assembly houses backwards to the PWB fabricator. (Regardless of whether it is liked or disliked by the PWB fabricators). ASPOCOMP, as a leader in advanced PWB technology, is developing these technologies to meet the needs of key Original Equipment Manufacturers (OEMs). The paper describes the present experiences with this new technology and details where there are technology limits. Material suppliers will be challenged to provide better solutions than exist today. Sequential versus parallel PWB manufacturing processes will be reviewed and the requirements to meet the manufacturing and cost targets for the next generation of PWBs will be discussed.

Increasing packaging density and the requirement for high performance electronic devices are driving high density interconnect (HDI) printed wiring board (PWB) technology towards utilization of the inner space of a PWB for component placement. Aspocomp has been manufacturing HDI PWBs at Salo for more than 5 years. The main focus has been on higher packaging density and on accommodating the needs of future chip packages. In volume production, cost and performance have to be balanced. As a result, manufacturing and material yields, process automation, the cost of materials and added value technologies like embedded passives are key considerations in meeting the high volume requirements of the marketplace. This paper describes how these parameters have evolved over time and how it has been possible to achieve the stringent tolerances required in the manufacturing processes.

The purpose of this paper is to study fabrication of optical‐PCBs on panel scale boards in a conventional modern PCB process environment. It evaluates impacts on board design and manufacturing with the developed optical board verifiers outlining challenges and requirements for manufacturing low‐loss waveguide structures and optical building blocks. The study aims to expand the current knowledge in the field by adding results obtained by utilizing industrial production infrastructure and developed scalable manufacturing processes to fabricate optical‐PCBs and board assemblies in high‐volumes and low‐cost manner.

Impacts on board design and manufacturing were studied with the developed optical technology verifiers. One verifier is optical‐PCB with embedded waveguides, integrated i/o couplers and optical vias. Another verifier is large size PCB with optical layer. A system‐level optical board assembly with 12.5 Gb/s Tx/Rx devices on surface mounted ball grid array (BGA) modules is designed for optical link analysis. Fabricated optical structures on verifiers are evaluated of their physical characteristics utilizing optical, SEM, LSCM analysis methods. Performance testing is conducted using standard optical transmission measurement methods and equipment.

The paper provides empirical results about fabrication of multimode optical waveguides with conventional PCB process equipment. Results suggest that current coating and imaging equipments are capable of producing optical waveguide patterns with high resolution and size accuracy. However, fabricators would require larger process window and defect tolerance for processing optical materials to obtain low‐loss waveguides with sufficient yields.

Because of the limited amount of design variants in production verifiers evaluated in this paper, some impacts like effect of base material, board construction, optical layer location and beam coupling solution were not evaluated. Likewise, impacts on long‐term stability and cost were not addressed. These factors however require further investigation to address technical feasibility of optical PCBs technology prior commercial high volume production.

The paper includes implications for the development of a fabrication methods and testing procedures for optical polymer waveguide layers on PCBs.

This paper fulfils need to provide results on design, fabrication and characterization of optical PCBs and backplanes from industrial fabricator's perspective. The paper provides input for end‐user and developers to evaluate technical performance, robustness, and maturity of building blocks and supply chain to support polymer waveguide based technology for intra‐system optical links.