Kao, Yu-LinYu-LinKaoWang, Lon A.Lon A.Wang2026-04-242026-04-242026-02-1621563950https://www.scopus.com/record/display.uri?eid=2-s2.0-105030466466&origin=resultslisthttps://scholars.lib.ntu.edu.tw/handle/123456789/737498Selective laser scanning enables spatially localized tuning of polyimide (PI) thermomechanical properties to mitigate thermally induced stress and warpage in advancedd 3DIC and optoelectronic packaging, without changing the global material selection. Laserprocessed PI films are characterized and the resulting property changes are incorporated into a 2D planestrain finiteelement model. The representative coupon/model has an inplane span of 10 mm and a total thickness of 50 μm (47 μm Si with 3 μm PI). Local modification is applied only in 1 mm corner patches to target highstress regions, while the remaining PI remains pristine. Using a minimalconstraint (freewarpage) boundary condition and meshobjective evaluation metrics (warpage and nearcorner areaaveraged stress), the localized modification reduces warpage and mitigates stress concentration; solder fatigue trends are assessed via inelastic strainenergy density per cycle (Darveaux).falseadvanced packagingco-packaged optics (CPO)finite element method (FEM)laser modificationpolyimidethermomechanical stresswarpagejournal article10.1109/tcpmt.2026.36652962-s2.0-105030466466