METHOD FOR FORMING SEMICONDUCTOR DEVICE FOR REDUCING RESISTANCE OF CONTACT SURFACE OF PAD AND PLUG

摘要

PURPOSE: A method for forming a semiconductor device for reducing the resistance of a contact surface of a pad and a plug is provided to reduce power consumption and a process defect by broadening the width of the upper surface of a contact pad in contact with a contact plug and by increasing the contact surface. CONSTITUTION: A contact pad(13) is formed in a substrate. A lower interlayer dielectric is formed over the contact pad. Upper and side portions of a structure are formed of a passivation layer having etch selectivity with respect to the lower interlayer dielectric. An upper interlayer dielectric is formed over the structure. The upper interlayer dielectric is eliminated by a self-aligned etch process using an etch mask pattern and the structure so that a contact hole(125) exposing at least a part of the upper surface of the contact pad is formed. An isotropic etch process is performed by using an etch material having selectivity with respect to the lower interlayer dielectric so that the width of the contact hole in an interval of the lower interlayer dielectric is extended as compared with an interval defined by the structure. An insulation layer is formed over the substrate while the contact hole is not filled. The insulation layer is etched back to expose the contact pad to the bottom of the contact hole and to form a spacer on the sidewall of the contact pad. A conductive layer is stacked to fill the residual space of the contact hole.