A process integration engineer introduced a RF passive device module to a $0\mathrm{.}5$ micron standard CMOS process technology that utilized three layers of DC sputtered aluminum metallization in an n$-$well process $($p$-$substrate$).$ The module was incorporated just prior to the end of the CMOS process after the final Al deposition was completed. The RF passive device utilized an iron ferrite layer to produce a very high inductance spiral wound coil that was connected to the circuitry through $2\mathrm{.}0$ micron deep vias to the Al metallization by $20$ micron diameter contacts in order to pass relatively high currents $($milliamps to tens of milliamps$).$ The technology required one $60$ minute $1100$C anneal to make the inductor itself function properly.

The Fe layer was $3$ microns thick.

The Al metallization layers were each $1$ micron thick.

The poly gate layer was $0\mathrm{.}3$ microns thick.

The feature sizes were all $1$ microns for the metal lines, $0\mathrm{.}5$ microns for contacts and poly, and $2$ microns minimum for the Fe layer.

S$/$D junctions were all $0\mathrm{.}3$ microns deep and the n$-$well was $5$ microns deep.

The interlayer dielectric isolation between the metallization layers, ILD$0$ through ILD$2,$ were all $2$ microns thick deposited phosphorus$-$doped silicon dioxide $($PSG$).$

The technology integration didn$$t work. Describe and provide a brief analysis of $4$ potential reasons why this integration failed and how you could resolve them.