Low pH barrier slurry based on titanium dioxide

A method of chemically-mechanically polishing a substrate, which method comprises:

• (i) contacting a substrate comprising at least one layer of ruthenium with a polishing pad and a chemical-mechanical polishing composition comprising:
• (a) an abrasive consisting of (A) particles consisting of titanium dioxide having a rutile structure and (B) particles consisting of titanium dioxide having an anatase structure, wherein an x-ray diffraction pattern of the particles has a ratio of X/Y of about 0.5 or more, wherein X is an intensity of a peak in an x-ray diffraction curve representing a d-spacing of about 3.24 Å, and Y is an intensity of a peak in an x-ray diffraction curve representing a d-spacing of about 3.51 Å, and
• (b) water,
• (ii) moving the polishing pad and the polishing composition relative to the substrate, and
• (iii) abrading at least a portion of the ruthenium to polish the substrate.