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Variation of Silicon Wafer Strength and Edge Chipping Induced by Residual Stresses at the Brick Bonding Interface
R. Koepge, K. Buehler, A. Langhans, F. Kaule, E. Velispahic
Simulation, Residual Stress, Silicon, Wafer Strength, Edge Chipping, Brick Bonding, Adhesives
Silicon Materials and Cells
Subtopic: Feedstock, Crystallisation, Wafering, Defect Engineering
Event: 36th European Photovoltaic Solar Energy Conference and Exhibition
Session: 2CV.2.24
352 - 357
ISBN: 3-936338-60-4
Paper DOI: 10.4229/EUPVSEC20192019-2CV.2.24
0,00 EUR
Document(s): paper, poster


These days, the wafering of silicon with the usage of the diamond wire process is well established. The huge experience of wafer manufacturers has enabled many process optimizations over the last decade. But, in detail regarding the wafering costs there are some parameters or process peculiarities that are not optimized yet. This study presents an analysis of a new brick bonding adhesive that is compared to the established two compound resin bonding glue. The new hot melt glue was analyzed regarding the stress state at the bonding interface, the chipping potential at the wafer edges and the wafer strength. The residual stresses at the bonding layer are justified by performing a simplified experiment and FEM simulation to calculate the existing stress state caused by glue curing. The edge chipping was evaluated by the usage of an automatic algorithm that was able to quantify the chipping events at the wafer edges by image analysis. The final wafer strength was determined by mechanical testing and Weibull analysis. In this work, the application of hot melt bonding was tested and the consequences to the wafer properties were analyzed. Our conclusion is that the hot melt bonding shows the potential to substitute the current resin-based glue.