Characterization and modeling of a typical curing material for photoresist films

• Published in: 2022 23rd International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE) pp. 1 - 7
• Main Authors: Peng, Chongnan, Morak, Matthias, Thalhamer, Andreas, Gschwandl, Mario, Fuchs, Peter, Tao, Qi, Krivec, Thomas, Antretter, Thomas, Celigueta, Miguel Angel
• Format: Conference Proceeding
• Language: English
• Published: IEEE 25-04-2022
• Subjects: Adaptation models; Curing; Imaging; Numerical models; Predictive models; Production; Semiconductor device measurement
• DOI: 10.1109/EuroSimE54907.2022.9758849

The photo imaging process is one of the most important advances in the production of printed circuit boards (PCBs). Especially, UV-curable resins are widely used in the semiconductor and microelectronics industries and are becoming increasingly popular due their options to modernize manufacturing processes, as the introduction of the Laser Direct Imaging (LDI). Compared to conventional UV exposure methods, the LDI process can generate patterns without mask film. This allows the production cycle to be significantly shortened, the alignment shift of the mask to be optimized and finer patters to be produced. To improve the efficiency as well as to reduce the need for field experiments to determine the most appropriate process parameters, a novel numerical simulation method is proposed. To this end a model is introduced which allows the calculation of the curing degree of the UV-resin as a function of the applied light intensity. Experimental investigations of the reaction kinetics of the photoreactive polymer serve as a basis for the formulation and calibration of the simulation models. Photo differential scanning calorimetry (photo-DSC) is used to determine the curing process and relevant parameters, such as the exothermic energy during the reaction. To ensure a realistic description of the photo imaging process by numerical methods, measurements of the curing degree are performed at different light intensities corresponding to real process conditions. Based upon the experimental results, a numerical material model is defined and implemented in a Finite Element Analysis (FEA), thus enabling the possibility to virtually assess and optimize the curing process of UV-reactive resins.