Semiconductor device and manufacturing method thereof

A method for manufacturing a semiconductor device, comprising:

• forming a layer stack over an etch stop layer, the layer stack comprising in order from the etch stop layer:
• a first layer;
• a second layer;
• and
• a third layer,
• wherein the first layer is made of a material selected from the group consisting of silicon oxide, silicon nitride, SiOC, titanium oxide, and titanium nitride,
• the second layer is made of a material selected from the group consisting of silicon oxide, silicon nitride, titanium oxide, and titanium nitride,
• the third layer is made of a material selected from the group consisting of amorphous silicon, amorphous carbon, aluminum oxynitride, silicon oxide, silicon nitride, aluminum oxide, silicon oxycarbide, and SiCOH,
• the first layer and the second layer are made of different materials, and
• the second layer and third layer are made of different materials;
• patterning the first layer to expose a portion of the second layer thereby forming a plurality of first lines extending in a first direction;
• patterning the second layer to form an opening extending in a second direction perpendicular to the first direction exposing a portion of the first layer;
• forming a fourth layer over exposed portions of the first layer and second layer, and over sidewalls of the third layer,
• wherein the fourth layer is made of a material selected from the group consisting of a silicon oxide, aluminum oxide, titanium oxide, silicon nitride, titanium nitride, silicon oxynitride, silicon oxycarbide, and silicon carbonitride, and
• the third layer and the fourth layer are made of different materials;
• exposing an upper surface of the second layer;
• removing the first lines;
• patterning the second layer and the first layer to form second lines extending along the first direction and third lines extending along the second direction.

A method for manufacturing a semiconductor device, comprising:

• forming a hard mask layer overlying a device layer of a semiconductor device,
• forming a mandrel underlayer over the hard mask layer,
• wherein the mandrel underlayer comprises a silicon oxide, silicon nitride, titanium oxide, titanium nitride, or combinations thereof;
• forming a first mandrel layer over the mandrel underlayer,
• wherein the first mandrel layer comprises amorphous silicon, amorphous carbon, or aluminum oxynitride;
• forming a second mandrel layer over the first mandrel layer,
• wherein the second mandrel layer comprises a silicon oxide, silicon nitride, aluminum oxide, silicon oxycarbide, or SiCOH;
• patterning the first mandrel layer and second mandrel layer to form a plurality of lines extending in a first direction exposing the mandrel underlayer;
• forming a plurality of openings in the mandrel underlayer extending in a second direction perpendicular to the first direction;
• forming a spacer layer over the mandrel underlayer and the second mandrel layer,
• wherein the spacer layer comprises a silicon oxide, aluminum oxide, titanium oxide, silicon nitride, titanium nitride, silicon oxynitride, silicon oxycarbide, silicon carbonitride, or combinations thereof, and
• wherein the spacer layer fills the plurality of openings in the mandrel underlayer;
• removing portions of the spacer layer to expose an upper surface of the mandrel underlayer and an upper surface of the second mandrel layer;
• removing the second mandrel layer and the first mandrel layer;
• and
• patterning, by using remaining portions of the spacer layer as a mask, the mandrel underlayer and the hard mask layer, to form a hard mask pattern with first hard mask pattern lines extending along the first direction and second hard mask pattern lines extending along the second direction.