Polishing method

A polishing method comprising the steps of:

• preparing a substrate which has silicon nitride as a stopper, a wiring metal, a barrier metal and an insulating material, and has at least a portion of the wiring metal, at least a portion of the barrier metal, and at least a portion of the insulating material to a direction of a surface subjected to polishing from the stopper;
• supplying a CMP slurry in between the surface subjected to polishing of the substrate and a polishing pad, and thereby polishing the wiring metal, the barrier metal and the insulating material that are positioned to the direction of the surface subjected to polishing from the silicon nitride;
• and
• stopping polishing, before the silicon nitride is exposed and the silicon nitride is completely removed,
• wherein the CMP slurry contains:
• (A) a copolymer of (a) a monomer that is anionic and does not contain a hydrophobic substituent, and (b) a monomer containing a hydrophobic substituent;
• (B) an abrasive grain;
• (C) an acid;
• (D) an oxidizing agent;
• and
• (E) a liquid medium,
• the component (B) has a zeta potential of +10 mV or more in the CMP slurry, and
• the component (A) has a copolymerization ratio between (a) and (b), wherein ((a):(b)) is 25:75 to 75:25 as a molar ratio, and
• a pH is 5.0 or less.

A polishing method comprising the steps of:

• preparing a substrate which has silicon nitride as a stopper, a wiring metal, a barrier metal, and an insulating material, has at least a portion of the wiring metal, at least a portion of the barrier metal, and at least a portion of the insulating material to a direction of a surface subjected to polishing from the stopper, and has a section in which the silicon nitride, the insulating material, the barrier metal, and the wiring metal are laminated in this order on the direction of the surface subjected to polishing;
• a first polishing step of removing at least a portion of the wiring metal positioned to the direction of the surface subjected to polishing from the silicon nitride, and thereby exposing a portion of the barrier metal;
• and
• a second polishing step of removing by CMP at least a portion of the barrier metal and a portion of the insulating material that are positioned to the direction of the surface subjected to polishing from the silicon nitride, thereby exposing the silicon nitride, and stopping polishing before the silicon nitride is completely removed,
• at least the second polishing step including supplying a CMP polishing liquid in between the surface subjected to polishing of the substrate and a polishing pad,
• wherein the CMP slurry contains:
• (A) a copolymer of (a) a monomer that is anionic and does not contain a hydrophobic substituent, and (b) a monomer containing a hydrophobic substituent;
• (B) an abrasive grain;
• (C) an acid;
• (D) an oxidizing agent;
• and
• (E) a liquid medium,
• the component (B) has a zeta potential of +10 mV or more in the CMP slurry, and
• the component (A) has a copolymerization ratio between (a) and (b), wherein ((a):(b)) is 25:75 to 75:25 as a molar ratio, and
• a pH is 5.0 or less.