Cmp polishing solution and polishing method

Abstract

The present invention relates to a CMP polishing liquid for polishing a substrate comprising at least a barrier metal, a metal film, and a silicon dioxide film or a substrate comprising at least a barrier metal, a metal film, a silicon dioxide film, and a low-k film, wherein: the polishing liquid contains abrasive particles, a metal oxide dissolving agent, an oxidizing agent, a water-soluble polymer, and an alkali metal ion; the surface potentials of the abrasive particles and the metal film upon polishing have the same sign and the product of the surface potential (mV) of the abrasive particles and the surface potential (mV) of the metal film is 250 to 10000; and pH is 7.0 to 11.0.

1 . A CMP polishing liquid for polishing a substrate comprising at least a barrier metal, a metal film, and a silicon dioxide film or a substrate comprising at least a barrier metal, a metal film, a silicon dioxide film, and a low-k film, wherein:
 the polishing liquid contains abrasive particles, a metal oxide dissolving agent, an oxidizing agent, a water-soluble polymer, and an alkali metal ion;   surface potentials of the abrasive particles and the metal film upon polishing have the same sign and a product of the surface potential (mV) of the abrasive particles and the surface potential (mV) of the metal film is 250 to 10000; and   pH is 7.0 to 11.0.   
     
     
         2 . The polishing liquid according to  claim 1 , wherein the abrasive particles form associated particles and an average secondary particle diameter of the associated particles is 120 nm or less. 
     
     
         3 . The polishing liquid according to  claim 1 , wherein a content of the abrasive particles is 1 to 20 mass %. 
     
     
         4 . The polishing liquid according to  claim 1 , wherein the abrasive particles comprise silica particles. 
     
     
         5 . The polishing liquid according to  claim 1 , wherein the metal oxide dissolving agent comprises at least one selected from the group consisting of citric acid, malonic acid, diglycolic acid, isophthalic acid, and methylsuccinic acid. 
     
     
         6 . The polishing liquid according to  claim 1 , the water-soluble polymer has a structure of the following formula (1):
   RO—X n —Y m —H  (1)
   wherein R represents an alkyl group, an alkenyl group, a phenyl group, a polycyclic phenyl group, an alkylphenyl group, or an alkenylphenyl group having 6 or more carbon atoms; X and Y represent an oxyethylene group and an oxypropylene group that optionally have a substituent on a side chain, respectively; n and m each represent an integer of 0 or more; and n+m is an integer of 4 or more.   
     
     
         7 . The polishing liquid according to  claim 1 , wherein the alkali metal ion is a potassium ion. 
     
     
         8 . A polishing method comprising a step of relatively moving a polishing platen and a substrate in a condition where the substrate is pressed against the polishing cloth, while the CMP polishing liquid according to  claim 1  is supplied onto the polishing cloth of the polishing platen, the substrate comprising at least a barrier metal, a metal film, and a silicon dioxide film or comprising at least a barrier metal, a metal film, a silicon dioxide film, and a low-k film.