Method of manufacturing semiconductor device including laser treatment for contact plug

A method of manufacturing a semiconductor device, the method comprising:

• providing a substrate;
• forming an insulating layer on the substrate;
• etching the insulating layer to form an opening that exposes the substrate;
• forming a contact plug in the opening and on the insulating layer;
• forming a metal layer on the contact plug;
• and
• irradiating the metal layer with a laser,
• wherein the irradiating of the metal layer with a laser comprises removing a void or a seam in the contact plug by directly heating the metal layer, resulting in Indirectly heating the contact plug, and
• wherein the method further comprises forming an insertion layer between the contact plug and the metal layer to prevent reaction or interdiffusion therebetween, and the irradiating of the metal layer with a laser is performed in a state where the insertion layer and the metal layer are disposed on the contact plug.