Method of manufacturing a semiconductor device

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

• forming a first gate structure on a cell region of a substrate, the substrate including the cell region and a peripheral circuit region;
• forming a bit line structure on the first gate structure;
• forming a preliminary contact plug layer including amorphous silicon on the substrate;
• forming a reflective layer structure on the preliminary contact plug layer, the reflective layer structure including a first reflective layer having a first refractive index and a second reflective layer having a second refractive index, the second refractive index being greater than the first refractive index;
• forming a contact plug layer from the preliminary contact plug layer, the forming the contact plug layer including performing a melting laser annealing (MLA) process of irradiating a laser on the reflective layer structure so the amorphous silicon of the preliminary contact plug layer is converted into polysilicon;
• and
• forming a capacitor on the contact plug layer, wherein
• a reflective ratio of light on the peripheral circuit region of the substrate is greater than a reflective ratio of the light on the cell region of the substrate.

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

• forming a first gate structure on a cell region of a substrate, the substrate including the cell region and a peripheral circuit region;
• forming a bit line structure and a second gate structure on the cell region and the peripheral circuit region, respectively, of the substrate;
• forming a preliminary contact plug layer including amorphous silicon on the substrate to cover the bit line structure and the second gate structure;
• forming a reflective layer structure on the preliminary contact plug layer, the reflective layer structure including a first reflective layer having a first refractive index and a second reflective layer having a second refractive index, the second refractive index being greater than the first refractive index, and a thickness of a portion of the second reflective layer on the cell region of the substrate being different than a thickness of a portion of the second reflective layer on the peripheral circuit region of the substrate;
• performing a melting laser annealing (MLA) process that includes irradiating a laser on the reflective layer structure so that the preliminary contact plug layer is converted into a lower contact plug layer including polysilicon;
• planarizing the lower contact plug layer to form a lower contact plug;
• forming an upper contact plug on the lower contact plug;
• and
• forming a capacitor on the upper contact plug.