Abstract: A method for fabricating a fine pattern of a semiconductor device is provided. The method includes forming a base layer, a first mask pattern having identical features of a first width with inclined sidewalls and a second mask pattern having identical features of a second width in sequence on a substrate, wherein a smallest distance between any two adjacent inclined sidewalls is equal to the second width. The base layer is etched by using the first mask pattern as an etch mask to form first openings of the second width and a fill layer is formed covering the substrate. The second mask pattern is removed to form second openings in the fill layer and then the first mask pattern and the base layer are etched through the second openings to form third openings. The fill layer and the first mask pattern are removed to form a pattern of the base layer having identical features of a third width, wherein the third width of the features of the base layer pattern is equal to the second width.

Abstract: A method for forming a bit-line contact plug includes providing a substrate including a transistor which includes a gate structure and a source/drain at both sides of the gate structure; forming a conductive layer, a bit-line contact material layer and a hard mask layer; performing an etching process using the conductive layer as an etching stop layer to etch the bit-line contact material layer and the hard mask layer and forming the bit-line contact plug on the source/drain. A transistor structure includes a gate structure and a source/drain at both sides of the gate structure, a conductive layer covering part of the gate structure and connected to the source/drain, and a bit-line contact plug disposed on the conductive layer and directly connected to the conductive layer.

Abstract: A method for forming a bit-line contact plug includes providing a substrate including a transistor which includes a gate structure and a source/drain at both sides of the gate structure; forming a conductive layer, a bit-line contact material layer and a hard mask layer; performing an etching process using the conductive layer as an etching stop layer to etch the bit-line contact material layer and the hard mask layer and forming the bit-line contact plug on the source/drain. A transistor structure includes a gate structure and a source/drain at both sides of the gate structure, a conductive layer covering part of the gate structure and connected to the source/drain, and a bit-line contact plug disposed on the conductive layer and directly connected to the conductive layer.