The compatibility of ALD and CVD metal deposition with mesoporous and microporous carbon-doped organosilicate glass (OSG) films was examined. Blanket film studies using TEM, TOF-SIMS, and positron lifetime spectroscopy demonstrate that ALD Wand TaN penetrate deep into the mesoporous film via the film's connected pore structure. In contrast, metal penetration into microporous OSG films was not observed. He and NH3 plasma pretreatments to the mesoporous OSG film surface did not seal the mesopores to ALD metal penetration, but the plasmas did damage the bulk of the mesoporous OSG film with varying severity. The results indicate that porosity, pore size, and/or pore structure regulate ALD/CVD precursor diffusion and that ALD metal deposition is a good probe of pore sealing strategies.