Self-aligned trench formation
AssigneeMicron Technology, Inc.
InventorsWerner Juengling, Richard Lane
Life of this patent
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Abstract
Methods for forming a semiconductor device include forming self-aligned trenches, in which a first set of trenches is used to align a second set trenches. Methods taught herein can be used as a pitch doubling technique, and may therefore enhance device integration. Further, employing a very thin CMP stop layer, and recessing surrounding materials by about an equal amount to the thickness of the CMP stop layer, provides improved planarity at the surface of the device.
Claims32
A method of forming a device, the method comprising:
- forming a layer of polysilicon on a substrate;
- forming a first set of trenches in the substrate, wherein remaining portions of the polysilicon layer remain above the substrate in inter-trench regions between trenches of the first set;
- filling the first set of trenches with a filler material, wherein the filler material extends upward to at least a level adjacent the remaining portions of the polysilicon layer;
- selectively etching the remaining portions of the polysilicon layer from the inter-trench regions;
- forming spacers on sidewalls of the filler material in the inter-trench regions;
- and
- etching a second set of trenches into the substrate between the spacers.
A method of forming a device on a substrate, comprising:
- forming an etch stop layer on the substrate;
- etching a plurality of first trenches through the etch stop layer and the substrate;
- filling the first trenches with an isolation material that protrudes above the substrate;
- forming spacers on sidewalls of the protruding portion of the isolation material;
- etching a plurality of second trenches between the spacers;
- filling the second trenches with a second filler material;
- and
- planarizing the second filler material and stopping planarizing on the etch stop layer.
A method of forming an integrated circuit, comprising:
- forming a structure on a substrate, the structure comprising a structural material and an etch stop, the etch stop having an upper surface and a lower surface;
- planarizing the structure and stopping planarizing on the etch stop;
- selectively recessing the structural material to be approximately coplanar with the lower surface of the etch stop;
- and
- selectively removing the etch stop.
Dependencies are inferred from the claim text.