The prevention of charge-induced corrosion of tungsten vias after metal etch has been stud-ied with several types of commonly used wet chemical solutions and two kinds of dielectric film materials, silicon dioxide and silicon oxynitride. It was found that one of the solutions, leaving essentially no polymer residue on metal lines, could effectively prevent corrosion of tungsten vias. Other solutions either produced minor residues or severe sidewall erosion on metal lines. This study has shown that the combination of wet treatment with oxynitride as the dielectric charge shielding film was as effective as other conventional methods for preventing tungsten vias corrosion. However, for metal lines capped with silicon dioxide, significant sidewall ero-sion, surface roughness, and polymer residue were observed. Chemical reaction mechanisms are proposed for the preservation of tungsten vias after metal etch.