Production solution for the definition of blind microvias in high density interconnect PCBs

Citation

(2000), "Production solution for the definition of blind microvias in high density interconnect PCBs", Circuit World, Vol. 26 No. 2. https://doi.org/10.1108/cw.2000.21726bad.001

Production solution for the definition of blind microvias in high density interconnect PCBs

Keywords Printed circuit boards, Microvias, Shipley Ronal

DynaVia 2000, a photoimageable dielectric material just released by Shipley Ronal in Europe, offers manufacturers of high density PCBs a reliable solution for volume production of microvias. Blind microvias may be formed in DynaVia 2000 by either laser ablation or photo-definition.

About 8 percent of the worldwide PCB production currently includes some sort of high density interconnect (HDI) design. This figure is predicted to increase significantly over the next few years, with the development of ever smaller, lighter electronic equipment.

Developed by IBM for use in their SLC (Surface Laminar Circuit) designs which is used exclusively in the ThinkPad^® notebook computer, DynaVia 2000 is now available for the first time to other manufacturers as a production-proven, high-yield, cost-effective technology. Its excellent electrical characteristics, such as dielectric constant (<3.5) and loss tangent (0.026), combine with its superior elongation (28 percent) and peel strength (10.5-11.3 N/cm) providing a robust material for use in any build-up design.

The new material is applied over a copper, single-sided, double-sided or multi-layer board using conventional vacuum lamination techniques. Microvias are defined, and then the material is cured. Finally, external circuitry - such as pads, lands and conductor lines - may be added using a conventional semi-additive plating process such as Shipley's Circuposit 4000. If additional dielectric layers are required, the process is simply repeated for each layer.

DynaVia 2000 is highly versatile, offering the same high electrical and mechanical performance with both laser- and photo-definition processes. This versatility allows manufacturers to select the most cost-effective method of microvia manufacture at each stage of the development cycle, without having to re-qualify the dielectric material.

Typically laser drilling will be used for prototype designs, followed by photo-definition of production volumes. DynaVia carries a UL 94 V-0 material rating and is qualified to strict IBM internal requirements.

For further information, please contact: Shipley Ronal. Tel: +44 (0)124 7665 4420; Fax: +44 (0)124 7665 4458; E-mail: cmilton@shipley.com