THROUGH SUBSTRATE VIAS

摘要

Through substrate vias (TSVs) are provided after substantially all high temperature operations needed to form a device region (26) of a first thickness (27) proximate the front surface (23) of a substrate wafer (20, 20') by: (i) from the front surface (23), forming comparatively shallow vias (30, 30') of a first aspect ratio containing first conductors (36, 36') extending preferably through the first thickness (27) but not through the initial wafer (20) thickness (21), (ii) removing material (22") from the rear surface (22) to form a modified wafer (20') of smaller final thickness (21') with a new rear surface (22'), and (iii) forming from the new rear surface (22'), much deeper vias (40, 40') of second aspect ratios beneath the device region (26) with second conductors (56, 56') therein contacting the first conductors (36, 36'), thereby providing front-to-back interconnections without substantially impacting wafer robustness during manufacturing and device region area. Both aspect ratios are desirably about < 40, usefully < 10 and preferably < 5.