Issue link: https://iconnect007.uberflip.com/i/1533904
54 SMT007 MAGAZINE I APRIL 2025 Figure 7: Reference test from Memtest86 showing the DRAM passing with no errors after an exposure of 350 rads. Figure 6: 2D X-ray images with various filter materials and thicknesses. exponential relationship between board thick- ness and dosage, suggesting that beyond a cer- tain thickness, increasing the thickness has a diminishing effect of reducing the dosage. e results from the functional test are shown in Figure 7. e BGA with on-pack- age DRAM was exposed in increments of 50 rad and, aer subsequent exposure, the per- formance was measured using the test setup shown in Figure 1. ere were no errors recorded by MemTest86 aer any of the exposures as shown in Figure 7. Even aer total exposure of 350 rads, MemTest86 gave no errors on the DRAM. e results indicate that even aer overexposure to three times the limit provided by DRAM manufacturer, no infant mortality failures were observed. However, the reliability of the DRAM over longer periods of usage may be reduced. Summary is paper outlines several mitigation strat- egies for minimizing radiation dosage during X-ray inspections, particularly in the context of printed circuit boards (PCBs). One key observation is that the PCB itself acts as an effective shield, significantly reducing radia- tion exposure. is relationship is shown in Figure 8. is protective effect was clearly demonstrated in the experimental results,