Mask layout and method for forming vertical channel transistor in semiconductor device using the same
A method for forming a vertical channel transistor in a semiconductor memory device includes: forming a plurality of pillars over a substrate so that the plurality of pillars are arranged in a first direction and a second direction crossing the first direction, and so that each of the pillars has a hard mask pattern thereon; forming an insulation layer to fill a regions between the pillars; forming a mask pattern over a resultant structure including the insulation layer, wherein the mask pattern has openings exposing gaps between each two adjacent pillars in the first direction; etching the insulation layer to a predetermined depth using the mask pattern as an etching barrier to form trenches; and filling the trenches with a conductive material to form word lines extending in the first direction.
1. A method for forming a vertical channel transistor in a semiconductor memory device, the method comprising:
forming a plurality of pillars over a substrate, the plurality of pillars being arranged in a first direction and a second direction crossing the first direction, and each of the plurality of pillars having a hard mask pattern thereon;
forming an insulation layer to fill regions between the plurality of pillars;
forming a mask pattern over a resultant structure including the insulation layer, wherein the mask pattern has openings only exposing gaps between each two adjacent pillars of the plurality of pillars and covers the other portions in the first direction;
etching the insulation layer to a predetermined depth using the mask pattern as an etching barrier to form trenches; and
filling the trenches with a conductive material to form word lines extending in the first direction.
2. The method of claim 1 , wherein the openings have a width in the first direction greater by a predetermined value than the gaps.
3. The method of claim 2 , wherein the predetermined value is greater than 0 nm but not greater than approximately 20 nm.
4. The method of claim 1 , wherein a length of the openings in the second direction is smaller than a width of each of the plurality of pillars in the second direction.
5. The method of claim 1 , wherein the openings have a shape of a bar or a box.
6. The method of claim 1 , wherein the hard mask pattern is formed of a nitride, and the insulation layer is formed of an oxide.
7. The method of claim 1 , wherein forming the trenches further comprises using a carbon fluoride (CF)-based gas.
8. The method of claim 1 , wherein forming the trenches is performed at a temperature of at least approximately 40° C.
9. The method of claim 6 , further comprising performing a wet etching process on an oxide after forming the trenches.
10. The method of claim 1 , wherein each of the plurality of pillars comprises surround type gate electrodes surrounding lower portions of the plurality of pillars,
forming the trenches ends when the surround type gate electrodes are exposed.