Manufacturing method of connection structure

Abstract

A manufacturing method of a connection structure includes the following steps. A dielectric layer is formed on conductive structures. Openings are formed in the dielectric layer and expose the conductive structures. A tungsten nucleation layer is conformally formed on the dielectric layer and in the openings. A nitrogen-containing treatment is performed on the tungsten nucleation layer. A deposition process is performed to form a tungsten filling layer on the tungsten nucleation layer. An interfacial layer is formed between the tungsten nucleation layer and the tungsten filling layer by the deposition process. A fluorine concentration of the interfacial layer is higher than that of the tungsten filling layer. A chemical mechanical polishing (CMP) process is performed to remove a part of the tungsten nucleation layer and a part of the tungsten filling layer for forming connection structures. The interfacial layer is removed by the CMP process.