Semiconductor device and method for fabricating the same

A semiconductor device comprising:

• a substrate;
• a plurality of first lower lines disposed over the substrate and extending in a first direction;
• a plurality of first upper lines disposed over the first lower lines and extending in a second direction intersecting the first direction;
• a plurality of first memory cells disposed at intersection regions between the first lower lines and the first upper lines;
• a first insulating layer pattern filled between the first memory cells;
• and
• a second insulating layer pattern disposed over the first insulating layer pattern and filled between the first upper lines while having a higher etch resistance than the first insulating layer pattern.

A method for fabricating a semiconductor device, comprising:

• forming a tungsten layer;
• converting a first hydrophilic surface of the tungsten layer into a hydrophobic surface;
• forming a first portion of an ultra-low temperature oxide (ULTO) layer over the tungsten layer;
• performing plasma treatment to the first portion of the ULTO layer using a Group VIII inert gas;
• and
• forming a second portion of the ULTO layer.