METHOD FOR PLANARIZING SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for planarizing a semiconductor device is provided to perform a uniform planarization in a chemical mechanical polishing(CMP) process without a loss of a mask nitride layer of a word line, by depositing an oxide nitride layer as a buffer layer such that the oxide nitride layer has a polishing rate slower than that of a plug formation layer. CONSTITUTION: The plug formation layer and the buffer layer are sequentially formed on the entire surface of a semiconductor substrate(100) having a self-aligned contact hole formed in an interlayer dielectric(130). A T-type mask is formed on the buffer layer. The buffer layer in a portion except a contact plug formation portion is removed by using the T-type mask. The T-type mask is eliminated. A CMP process is performed to planarize the upper portion of the word line.