Heavy polymer residue has been observed on the sidewall of thick metal during the process release. The thickness of metal line is more than 3 micron. This thick polymer residue on the aluminum metal sidewall is seen from tilt Scanning Electron Microscope (SEM) profile analysis. This polymer residue on the metal sidewall with chlorine (Cl2) trapped will result in metal corrosion. The focus on this paper is on the removal of this polymer residue on the thick metal sidewall. The experiments were run with splits of varying the chemical dispensing time and the rinsing time in the process. The success criteria are determined by passing the Defect Source Analysis (DSA) and tilt SEM profile analysis. These wafers are sent for electrical test, wet box test (corrosion test) and electrical sort test to ensure the reliability of the post metal cleaning condition.