Abstract: The present: invention addresses the problem of providing a silicon nitride etching liquid composition which is capable of selectively etching Si3N4 with a practical etching selectivity with respect to SiO2, while suppressing regrowth of SiO2, and which is also capable of suppressing pattern collapse of an SiO2 film in the production of a 3D nonvolatile memory cell. A silicon nitride etching liquid composition for producing a 3D nonvolatile memory cell, which contains phosphoric acid, one or more silane coupling agents and water, but which does not contain ammonium ions.

Abstract: The present: invention addresses the problem of providing a silicon nitride etching liquid composition which is capable of selectively etching Si3N4 with a practical etching selectivity with respect to SiO2, while suppressing regrowth of SiO2, and which is also capable of suppressing pattern collapse of an SiO2 film in the production of a 3D nonvolatile memory cell. A silicon nitride etching liquid composition for producing a 3D nonvolatile memory cell, which contains phosphoric acid, one or more silane coupling agents and water, but which does not contain ammonium ions.

Abstract: Disclosed is a silicon nitride etching liquid composition for manufacturing 3D nonvolatile memory cells, etc., which comprises phosphoric acid, a hydrolysate of a water-soluble silicon compound, and water.