Method of manufacturing integrated deep and shallow trench isolation structures
View Patent ↗A method of forming an integrated deep and shallow trench isolation structure comprises depositing a hard mask on a film stack having a plurality of layers formed on a substrate such that the hard mask is deposited on a furthermost layer from the substrate, imprinting a first pattern into the hard mask to define an open end of a first trench, imprinting a second pattern into the hard mask to define an open end of a second trench, and etching into the film stack the first trench to a first depth and the second trench to a second depth such that the first trench and the second trench each define a blind aperture in the surface of the film stack.
1. A method of forming a semiconductor device including deep and shallow trench isolation structures, the method comprising:
providing a substrate with a semiconductor layer;
depositing a hard mask layer over the substrate semiconductor layer;
etching the hard mask layer in a first etch using a first mask pattern to form deep trench openings with blind ends terminating at the substrate semiconductor layer;
after the first etch, etching the hard mask layer in a second etch using a second mask pattern to form shallow trench openings with blind ends terminating in the hard mask layer, at least one shallow trench opening at least partially overlapping at least one deep trench opening;
after the second etch, etching the substrate semiconductor layer and partially etching the hard mask layer in a third etch to deepen the deep trench openings further into the semiconductor layer, and to remove portions of the hard mask layer remaining in the shallow trench openings but leave partially etched portions of the hard mask layer remaining at locations away from the shallow trench openings and deep trench openings;
after the third etch, etching the semiconductor layer in a fourth etch to deepen the shallow trenches and the deep trenches, with remaining partially etched portions of the hard mask acting to shield etching at locations away from the shallow trench openings and deep trench openings;
following the fourth etch, forming a layer of insulation material to simultaneously fill the deep trenches and shallow trenches; and
after filling the deep trenches and shallow trenches, planarizing to remove portions of the insulation material.
2. A method of forming a semiconductor device including deep and shallow trench isolation structures, the method comprising:
providing a film stack on a substrate; the substrate including a silicon layer formed over a buried first oxide layer, and the film stack including a second oxide layer formed over the silicon layer, and a nitride layer formed over the second oxide layer;
depositing a hard mask layer over the film stack;
forming a first layer of photoresist with a first pattern over the hard mask layer; the first pattern defining openings of deep trenches;
selectively etching the hard mask layer, nitride layer and second oxide layer through the patterned first layer of photoresist in a first etch to form the deep trench openings with blind ends terminating at or in the silicon layer;
following the first etch, removing the patterned first layer of photoresist;
following removing the patterned first layer of photoresist, forming a second layer of photoresist with a second pattern over the hard mask layer; the second pattern defining openings of shallow trenches, at least one shallow trench opening being defined to at least partially overlap at least one deep trench opening, and at least one deep trench opening not being overlapped by a shallow trench opening;
selectively partially etching the hard mask layer through the patterned second layer of photoresist in a second etch to form the shallow trench openings with blind ends terminating in the hard mask layer;
following the second etch, removing the patterned second layer of photoresist;
following removing the patterned second layer of photoresist, simultaneously etching the silicon layer and partially etching the hard mask layer in a third etch to deepen the deep trenches so that their blind ends terminate at or in the buried first oxide layer, and to remove portions of the hard mask layer remaining in the shallow trench openings but leave partially etched portions of the hard mask layer remaining at locations away from the shallow trench openings and deep trench openings;
following the third etch, selectively etching the second oxide layer and nitride layer from the shallow trench openings in a fourth etch to deepen the shallow trenches; the remaining partially etched portions of the hard mask acting to shield the second oxide layer and nitride layer from etching at locations away from the shallow trench openings and deep trench openings;
following the fourth etch, simultaneously forming an oxide liner on exposed surfaces of the silicon layer in the deep trenches and shallow trenches; and
simultaneously filling the oxide lined deep trenches and shallow trenches with oxide insulation filling material over the oxide liner.
3. The method of claim 2 , further comprising planarizing with chemical-mechanical polishing after filling the deep trenches and shallow trenches with oxide insulation filling material.
4. The method of claim 3 , wherein the second oxide layer comprises silicon oxide.
5. The method of claim 4 , wherein the nitride layer comprises silicon nitride.
6. The method of claim 4 , wherein the oxide insulation filling material comprises silicon oxide.