Patterned 100 nm trenches with an aspect ratio of 3.5 are filled at a nominal current density of -6.6 mA/cm(2). A low acid copper plating bath is used with the accelerator bis(3-sulfopropyl)-disulfide (SPS) and one of three suppressor molecules: Poly(ethylene glycol) (PEG) 3350, poly(propylene glycol) (PPG) 725, and an ethylene-propylene-ethylene (EPE) oxide triblock copolymer at a molecular weight of 2000 g/mol. All suppressors result in superconformal filling, although the filling rates vary widely. EPE 2000 results in the most rapid filling, metallizing the features without voids in 5 s under some conditions. The superior performance of EPE 2000 is attributed to its high suppression strength, which is greater than either PEG 3350 or PPG 725 at the relevant plating potentials. EPE 2000 filling becomes more rapid as suppressor concentration decreases, down to 100 ppm, which is attributed to a strong correlation between EPE 2000 concentration and adsorption time. EPE 2000 performance is also improved as SPS concentration decreases, a result in contrast to literature observations on larger (500 nm) features. A simple expression is developed to demonstrate that the time scales of suppression, acceleration, and filling can account for this result.