Laser (UV) microvia application in cellular technology

In the past three years, microvia drilling using laser technology has become the dominant method of producing blind vias smaller than 150 m. The ablation characteristics of the materials used in the manufacture of PWBs can be divided into three categories: organics, glass, and metals. Organics are composed of resins and epoxies commercially available from a variety of vendors. Two types of resins that are typically used for microvia formation in the telecommunication applications are resin coated copper foil® (RCC or RCF) for subtractive PCB process, and thermal-curing resin (TCR) for additive PCB process respectively. This paper details the basics of UV YAG laser capabilities, alignment techniques, plating tests, reliability tests, manufacturable microvia design rules, and production experiences.