Stress-tailored figure correction of thin borosilicate glass by patterned excimer laser irradiation

Spatially homogeneous irradiation of borosilicate glass with an ArF excimer laser at fluences near or above the ablation threshold induces equibiaxial stress at the irradiated surface, causing the substrate to bend in a manner similar to that caused by a coated film. In contrast, patterned irradiation generates antibiaxial stress components, which, when appropriate parameters are selected, enable the decoupling of bending in two orthogonal directions. We demonstrate here that patterned irradiation can not only counteract stress introduced by a film but also pre-existing surface deformations. This approach yields figure-corrected samples with significantly improved planarity compared to the pristine substrates.