Abstract: Fan-out panel-level packaging （FOPLP） technology demonstrates significant advantages in heterogeneous chip integration and cost reduction, yet the increase in substrate size exacerbates the thermal stress warpage. Aimed at the heating and cooling processes of large-size glass substrates in vacuum chambers, a series of validation experiments were designed to investigate the effects of different pressure conditions （10^-3, 20, 100 and 10⁵ Pa） and N₂ gas flow assistance on the thermal behavior and temperature distribution of the substrates. The results show that under the same heating parameters and duration, the lower degas chamber pressure causes slower substrate heating rate and larger temperature difference between the center and the corner, while the opposite trend is observed during the cooling process. When the chamber pressure is approximately 100 Pa, the substrate surface provides the most stable heating condition. Introducing a low flow rate of N₂ at 100 Pa can improve the heating and cooling efficiency, and maintain the the edge and the center temperature difference at 5-10 ℃.

Key words: FOPLP, glass substrate, degas, N₂ flow assistance, thermal stress warpage