Method for processing a substrate
A method for processing a substrate includes forming a first mask over a mask line and forming a patterned mask by patterning a mask layer using the first mask as an etch mask. The first mask extending over sidewalls of the mask line and the mask layer is under the mask line. The method further includes forming a pillar and a line under the pillar from a target layer with an etch process by using the patterned mask layer as another etch mask.
1 . A method for processing a substrate, the method comprising:
forming a first mask over a mask line, the first mask extending over sidewalls of the mask line;
forming a patterned mask by patterning a mask layer using the first mask as an etch mask, the mask layer being under the mask line; and
forming a pillar and a line under the pillar from a target layer with an etch process by using the patterned mask layer as another etch mask, the line surrounding the pillar in a top view.
2 . The method of claim 1 , wherein the pillar and the line comprise a conductive material.
3 . The method of claim 2 , wherein the conductive material comprises ruthenium.
4 . The method of claim 1 , wherein the first mask comprises a round shape in a top view.
5 . The method of claim 1 , wherein the first mask comprises a first material and the mask line comprises a second material, the second material being different from the first material.
6 . The method of claim 5 , wherein the first material is a nitride.
7 . The method of claim 5 , wherein the second material is an oxide.
8 . The method of claim 1 , wherein the line has curved sidewalls adjacent the pillar in the top view.
9 . A method for processing a substrate, the method comprising:
forming a tone inversion mask between portions of an upper hardmask;
forming a pillar mask over a line of the tone inversion mask;
removing the upper hardmask, the removal of the upper hardmask exposing portions of a lower hardmask layer;
transferring a pattern of the pillar mask and the tone inversion mask to the lower hardmask layer; and
etching a conductive layer under the patterned lower hardmask layer by using the patterned lower hardmask layer as an etching mask, the etching forming a line and a pillar over the line.
10 . The method of claim 9 , wherein the pillar mask extends over the portions of the upper hardmask.
11 . The method of claim 9 , wherein the line and the pillar comprise a same conductive material.
12 . The method of claim 11 , wherein the same conductive material is ruthenium.
13 . The method of claim 9 , wherein forming the pillar mask comprises:
depositing a pillar hardmask layer over the tone inversion mask and the upper hardmask;
patterning a pillar photoresist mask over the pillar hardmask layer; and
transferring a pattern of the pillar photoresist mask to the pillar hardmask layer with an etch process.
14 . The method of claim 13 , wherein the etch process used to transfer the pattern of the pillar photoresist mask to the pillar hardmask layer is also used to remove the upper hardmask.
15 . The method of claim 14 , wherein the pillar hardmask layer and the upper hardmask are a same material.
16 . The method of claim 13 , wherein forming the pillar mask further comprises measuring critical dimensions of the pillar mask with a scanning electron microscope.
17 . The method of claim 13 , wherein forming the pillar mask further comprises measuring the pillar mask for misalignment over the line of the tone inversion mask with a scanning electron microscope.
18 . The method of claim 13 , wherein forming the pillar mask further comprises trimming the pillar mask with a gas cluster ion beam.
19 . The method of claim 9 , wherein the line and the pillar are formed with a single etch process.
20 . A method for processing a substrate, the method comprising:
forming a pillar mask over a mask line, the mask line being over a hardmask layer, the hardmask layer covering a conductive layer;
forming a patterned hardmask by transferring a pattern of the pillar mask and the mask line to the hardmask layer;
removing a portion of the mask line, a remaining portion of the mask line being covered by the pillar mask;
removing the pillar mask;
etching the conductive layer using the remaining portion of the mask line and the patterned hardmask as a first etch mask;
removing a portion of the patterned hardmask, a remaining portion of the patterned hardmask being covered by the remaining portion of the mask line; and
forming a conductive pillar over a conductive line by further etching the conductive layer using the remaining portion of the patterned hardmask as a second etch mask, the conductive pillar being under the second etch mask.
21 . The method of claim 20 , wherein the conductive line and the conductive pillar are ruthenium.
22 . The method of claim 20 , wherein the conductive pillar is formed on a base portion of the conductive line, the base portion of the conductive line comprising a round shape in a plan view.
23 . The method of claim 20 , wherein etching the conductive layer using the remaining portion of the mask line and the patterned hardmask comprises forming a trench in the conductive layer.