Patent ID: 8932479
Filing Date: 2015-01-13
Classification: C09G,C09K,H01L

Abstract:
1. A polishing liquid which is used for chemical mechanical polishing of a body to be polished in a planarization process for fabrication of a semiconductor integrated circuit, in which the body to be polished comprises at least a first layer comprising polysilicon or a polysilicon doped with an impurity element of P or B, and a second layer comprising at least one selected from the group consisting of silicon oxide, silicon nitride, silicon carbide, silicon carbonitride, silicon oxycarbide, and silicon oxynitride, wherein the polishing liquid comprises the following components (A), (B), and (C), has a pH of from 1.5 to 7.0, and selectively polishes the second layer with respect to the first layer: (A) colloidal silica particles having a negative ζ potential; (B) phosphoric acid or an organic phosphonic acid compound represented by the following Formula (1) or Formula (2): wherein, in Formula (1), a represents 1 or 2; R in Formula (2), R (C) an anionic surfactant having at least one group represented by the following Formula (I), Formula (II), Formula (III), or Formula (IV): wherein, in Formulae (I) to (IV), each X independently represents a hydrogen atom, lithium, sodium, potassium, or a quaternary ammonium cation, and wherein the polishing liquid is configured such that, when the second layer comprises silicon oxide and silicon nitride, the body is polished at a ratio represented by RR(silicon oxide)/RR(p-Si) in a range of from 1.5 to 200, and a ratio RR(silicon nitride)/RR(p-Si) in a range of from 1.5 to 200, RR(p-Si) indicating a polishing rate of the first layer, and RR(silicon oxide) and RR(silicon nitride) respectively indicating polishing rates of the silicon oxide and silicon nitride in the second layer.