Microscopic-scale trenches that were formed on silicon wafers were filled with polyamic acid (PM) and polyimide (PI) that consisted of the pyromellitic dianhydride (PMDA)-2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFDB) pair with the aid of supercritical carbon dioxide (scCO(2)) and 20mol% N,N-dimethylformamide (DMF) at 50 and 75 degrees C and at monomer concentrations of 2.0 x 10(-2)mol/dm(3) each. Most of the trenches were well filled with the polymer, which consisted mostly of PAA. Moreover, PAA and PI that consisted of the PMDA-4,4'-diaminodiphenyl ether (ODA) pair was also investigated at deposition temperatures ranging from 50 to 150 degrees C and at monomer concentrations of 2.0x 10(-2)mol/dm(3) each. The trenches were completely filled with PM and PI at 50 degrees C. Slight shrinkage of the deposited polymers inside the trenches was observed after thermal imidization.