Polishing of transition metals
The invention provides compositions useful in the polishing of transition metal-containing surfaces typically found on microelectronic devices. In one aspect, the invention provides a composition comprising: a liquid carrier; titania abrasive particles, wherein the particles are at least partially coated with alumina or amorphous silica to provide coated titania abrasive particles; wherein the coated titania abrasive particles have an average diameter of about 50 nm to about 250 nm; and a corrosion inhibitor. The invention, the compositions are advantageously utilized to polish microelectronic device substrates having transition metal-containing surfaces thereon. In certain embodiments, the surfaces are chosen from molybdenum and ruthenium-containing films and show markedly improved selectivity relative to thermal oxide.
1. A composition comprising:
a liquid carrier;
titania abrasive particles, wherein the particles are at least partially coated with alumina or amorphous silica to provide coated titania abrasive particles;
wherein the coated titania abrasive particles have an average diameter of about 50 nm to about 250 nm; and
a corrosion inhibitor, wherein the pH is about 2 to about 5.
2. The composition of claim 1 , wherein the coated titania abrasive particles are coated with alumina.
3. The composition of claim 1 , wherein the coated titania abrasive particles are coated with amorphous silica.
4. The composition of claim 1 , wherein the corrosion inhibitor is a cationic surfactant.
5. The composition of claim 4 , wherein the corrosion inhibitor is chosen from benzalkonium chloride and benzalkonium bromide.
6. The composition of claim 1 , further comprising at least one oxidizing agent.
7. The composition of claim 6 , wherein the oxidizing agent is chosen from hydrogen peroxide and periodic acid.