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APRIL 2025 I SMT007 MAGAZINE 55 Figure 8: Effect of board and substrate geometries on the X-ray dosage absorbed by DRAM. highlighting the importance of considering the board's material properties during inspec- tion. e study also examined the impact of inspection time on dosage, revealing a direct correlation: longer inspection times result in higher radiation exposure. is finding emphasizes the need to optimize inspection duration to minimize dosage without com- promising the thoroughness of the inspec- tion. Another critical factor discussed is the choice of filter material. Copper was identi- fied as the most effective filter for shielding radiation, significantly reducing dosage lev- els. However, this reduction in dosage comes at a cost, as the images produced with cop- per filters were of very poor quality due to the diminished X-ray penetration. Additionally, the paper explores the rela- tionship between material thickness and dosage, finding that this relationship fol- lows a decreasing exponential trend. As material thickness increases, the reduc- tion in dosage becomes marginal, indicat- ing diminishing returns with further thick- ness enhancements. is paper also investigated the radiation tol- erance of PCB assemblies housing BGAs with on-package memory. It was noted that there was no initial degradation of the performance of the DRAM observed even aer overexpo- sure to several times the recommended limit of DRAM exposure from manufacturer.