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AUGUST 2019 I PCB007 MAGAZINE 63 µm. Results are shown in Figure 6. As shown, no dimple was observed up to 90 x 60 µm via filling. However, larger vias—such as 100 x 80 µm—had a 4 µm dimple. Bath Life Study After the initial performance evaluation, a bath was aged up to 150 Ah/L. The volume of the bath was 8 L. The plating cycle for each plating was 15 ASF for 45 minutes, and addi- tive concentration was the same as tabulated in Table 1. During the aging, a test panel was plated at every 50 Ah/L, cross-sectioned, and evaluated under the microscope. The test board consist- ed of 60 x 35 µm vias and with various L/S for fine lines. Plating cycle was adjusted to ob- tain around 15 µm on the surface. Throughout the aging process, the lines showed Profile % in the range of 10–15% and occasionally 15– 20% consistent with the initial performance tests. R-value was between 1–2 with flat pad plating. Through-hole fill capability was tested using board thicknesses of 40 and 60 µm. Hole di- ameters were 40 and 50 µm, respectively, for the two boards. Results are shown in Figure 7. Plating cycle was 1.24 ASD for 60 minutes. As shown in Figure 7, the X-hole filling was excel- lent with Process I. Figure 6: Filling capability of different size vias 90 x 25, 80 x 35, 90 x 60, and 100 x 80 µm, respectively. Table 2: Bath aging test results profile % for 18/25, L/S, and R-value up to 150 Ah/L.