Abstract:
Circuit boards are manufactured by forming a substrate with a dielectric surface and laminating a metal foil onto the substrate. The metal foil is patterned to form a first wiring layer. A permanent photoimagable dielectric layer is formed over the wiring layer and via holes are formed through the dielectric layer over pads and conductors of the wiring layer. Holes are formed through the substrate and substrate surfaces including the photoimagable dielectric, walls of the via holes, and walls of the through holes subjected to an electroless copper plating process. The process includes seeding the surface, coating the surface with a first solution containing surfactant and electroplating in a second solution in which the level of surfactant is regulated by determining the surface tension and metering surfactant addition to the second solution depending on the determination of surface tension. The copper plating on the photoimagable dielectric is patterned to form an exterior wiring layer which is covered by solder resist with windows over lands around the through holes and surface mount connection pads of the exterior wiring layer to form a high density circuitized substrate. Surface mount components and/or pin in hole components are attached to the circuitized substrate with solder joints between terminals of the components and the lands and/or connection pads to form a high density circuit board assembly. One or more of the circuit board assemblies are mounted in an enclosure with a power supply, CPU, RAM, and I/O means to form an information handling system with increased performance due to shorter signal flight times due to the higher device density.
Abstract:
A process of fabricating a circuitized structure is provided. The process includes the steps of providing an organic substrate having circuitry thereon; applying a dielectric film on the organic substrate; forming microvias in the dielectric film; sputtering a metal seed layer on the dielectric film and the microvias; plating a metallic layer on the metal seed layer; and forming a circuit pattern thereon.
Abstract:
A process for making a circuitized substrate is defined wherein the substrate is treated with two different, e.g., additive and subtractive, metallization processes. The process is thus able to effectively produce substrates including conductive features, e.g., high density circuit lines and chip heat-sinking pads, of two different degrees of resolution in a cost effective and expeditious manner. The resulting product is also defined.
Abstract:
A PROCESS OF FABRICATING A CIRCUITIZED SUBSTRATE IS PROVIDED WHICH COMPRISING THE STEPS OF: PROVIDING AN ORGANIC SUBSTRATE (12) HAVING CIRCUITRY (14) THEREON; APPLYING A DIELECTRONIC FILM (16, 30) ON THE ORGANIC SUBSTRATE; FORMING MICROVIAS (18) IN SAID DIELECTRIC FILM; SPUTTERING A METAL SEED LAYER (20) ON THE DIELECTRIC FILM AND IN SAID MICROVIAS; PLATING A METALLIC LAYER (22) ON THE METAL SEED LAYER; AND FORMING A CIRCUIT PATTERN THEREON.(FIGURE 1 (E))