Laue microdiffraction evaluation of bending stress in Au wiring formed on chip-embedded flexible hybrid electronics

Au redistribution layers 10 to 100 mu m wide were fabricated on heterogeneously integrated advanced flexible hybrid electronics (FHE) substrates formed by a die-first approach based on fan-out wafer-level packaging. The formed Au metal wiring was meticulously studied for locally induced mechanical stress upon bending (bending radius, BR 20 mm) using Laue microdiffraction (L mu D) with synchrotron radiation. It was inferred from the L mu D data that upon bending the FHE substrate up to the BR of 20 mm, the Au metal wiring (10 mm long, 100 mu m wide, and 500 nm thick) experienced mechanical bending stress amounting to 250 similar to 300 MPa. The stress values obtained from the L mu D studies were close to the stress value of 350 MPa obtained by simulation.

Automated summary

The study examined the mechanical stress induced in Au metal wiring on FHE substrates up to a bending radius of 20 mm. Results showed that the stress experienced by the Au metal wiring was approximately 250 to 300 MPa, which closely matched the simulated value of 350 MPa.