METHOD OF FORMING CONTACT PLUG OF SEMICONDUCTOR DEVICE TO SECURE CONTACT MARGIN AND REDUCE CONTACT RESISTANCE USING CONTACT HOLE WITH LARGE UPPER CD

摘要

PURPOSE: A method of forming a contact plug of a semiconductor device is provided to secure a contact margin and to reduce contact resistance between a contact plug and an upper metal part such as a bit line or a storage node electrode by obtaining a large upper CD(Critical Dimension) from a contact hole using a process of flowing a lower insulating layer. CONSTITUTION: A lower insulating layer(25) is formed on a semiconductor substrate(11) with gate electrodes. Contact holes for exposing selectively the substrate to the outside between the gate electrodes are formed in the lower insulating layer by performing a self-aligned etching process using a contact mask. An upper CD of each contact hole is increased by flowing the lower insulating layer using a heat treatment. A contact plug(29) is filled in the contact hole.