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AssigneeInternational Business Machines Corporation
InventorsAshwinkumar C. Bhatt, Brant S. Blomberg, Ross W. Keesler, Michael V. Longo, Eboney J. N. Smith
Estimating the term…
A hybrid photolithography process for printed circuit board patterning combines two types of photoresist applications to achieve superior protection of printed circuit board (PCB) ‘plated through holes’ (PTH). In a first step, electro-deposited (ED) photoresist (also known as “ED resist”) is applied to a fully copper plated PCB including the ‘plated through holes’ to protect the outer layers and the ‘plated through holes’ from copper etchant solution. In a second step, the electro-deposited photoresist is imaged (exposed) and patterned (developed). In a third step, after developing the circuit image, a layer of Dry Film resist is applied to the panel of the PCB on top of the developed electro-deposited (ED) photoresist. This Dry Film resist layer will ‘tent’ the plated through holes by adding an extra layer of protection to the plated through holes. In a fourth step, the dry film resist is then exposed and developed. At this point, the PCB is etched as normal and all subsequent processing remains unchanged.
A photolithography process for printed circuit board patterning, the printed circuit board being copper plated and including a set of copper plated outer layers and one or more copper plated through holes, comprising the steps of:
A method of patterning a printed circuit board, said board including copper plated external layers further including other circuitization features and one or more through holes each further including a copper plated internal barrel, comprising the steps of:
A method of manufacturing a printed circuit board, comprising the steps of:
Dependencies are inferred from the claim text.