Inorganic capping layers in advanced photosensitive polymer based RDL processes: processing and reliability

In this work, thin inorganic ALD-deposited capping layers are integrated into polymer-based redistribution layer (RDL) processes with 2–4
$\mu \mathrm{m}$
line/space. The primary objective of enhanced reliability is shown, with secondary process improvements detailed. Impact and respective mitigation on Lithography process reviewed and the introduction of the capping etch are further detailed.