The present invention relates to a liquid additive for etching silicon nitride and silicon oxide layers, a metal ink including the same for forming silicon solar cell electrodes and a method for manufacturing silicon solar cell electrodes. More particularly, it relates to a liquid additive including metal nitrate, metal acetate, or hydrates thereof and a metal ink for forming silicon solar cell electrodes, mixed with the liquid additive and a metal. Further, it relates to a method for manufacturing silicon solar cell electrodes comprising a one-step non-contact printing for etching of a silicon nitride layer or silicon oxide layer and forming electrodes.