Process for increasing feature density during the manufacture of a semiconductor device
A method used during the manufacture of a semiconductor device comprises the formation of a first patterned layer having individual features of a first density. Through the formation and etching of various layers, for example conformal layers and a spun-on layer, a second patterned layer results which comprises individual features of a second density, which is about three times the first density. An in-process semiconductor apparatus formed using the method, and a system comprising the semiconductor apparatus formed according to the method, is also described.
1. A method used to form a semiconductor device, comprising:
forming a patterned-first-support layer comprising a plurality of features over a layer to be etched, wherein each of the patterned-first-support layer features comprises first and second vertically oriented sidewalls;
after forming the patterned-first-support layer, forming a patterned-first-top-masking layer comprising a plurality of spacers, with each of the patterned-first-top-masking spacers being formed on a respective one of the vertically oriented sidewalls of a respective one of the patterned-first-support layer features;
prior to removing the patterned-first-support layer, forming a patterned-second-support layer comprising features, wherein each of the patterned-second-support layer features contacts a respective one of the patterned-first-top-masking layer spacers, and wherein each of a plurality of the patterned-second-support layer features is separated from an adjacent one of the patterned-second-support layer features by a gap;
prior to removing the patterned-first-support layer and the patterned-second-support layer, forming a patterned-second-top-masking layer which fills the gaps and comprises a plurality of spacers, wherein each of the plurality of patterned-second-top-masking layer spacers is separated from an adjacent one of the patterned-first-top-masking layer spacers by a respective one of the plurality of patterned-second-support layer features;
removing the patterned-first-support layer and the patterned-second-support layer; and
subsequent to removing the patterned-first-support layer and the patterned-second-support layer, etching the layer to be etched using patterned-first-top-masking layer and the patterned-second-top-masking layer as a mask.
2. The method of claim 1 further comprising:
forming an etch stop layer over the layer to be etched;
forming the patterned-first-top-masking layer and the patterned-second-top-masking layer on the etch stop layer;
patterning the etch stop layer using the patterned-first-top-masking layer and the patterned-second-top-masking layer as a pattern; and
etching the layer to be etched using the etch stop layer as a mask.
3. The method of claim 1 further comprising:
forming a bottom masking layer over the layer to be etched;
forming an etch stop layer over the bottom masking layer;
forming the patterned-first-top-masking layer and the patterned-second-top-masking layer on the etch stop layer;
patterning the etch stop layer using the patterned-first-top-masking layer and the patterned-second-top-masking layer as a pattern;
patterning the bottom masking layer using the pattern of the etch stop layer as a pattern;
etching the layer to be etched using the bottom masking layer as a mask.
4. The method of claim 3 further comprising trim etching the patterned bottom masking layer.
5. The method of claim 1 wherein forming the patterned-second-support layer comprises using a gas modulated etch process to form the patterned-second-support layer.
6. The method of claim 1 further comprising:
forming the plurality of patterned-first-support layer features to a first width;
forming the plurality of patterned-first-top-masking spacers to a second width which is about the same as the first width; and
forming the plurality of patterned-second-support layer features to a third width which is about the same as the first width, wherein a distance which spans each of the gaps is about the same as the first width.
7. The method of claim 6 wherein the first width, the second width, the third width, and the distance which spans each of the gaps is each about 33 nanometers.
8. A method used to form a semiconductor device, comprising:
forming a plurality of first-support features over a material to be etched, wherein each first-support feature comprises first and second vertically oriented sidewalls;
after forming the plurality of first-support features, forming a plurality of first-mask features, wherein a respective one of the first-mask features is formed on each vertically oriented sidewall of each first-support feature;
prior to removing the plurality of first-support features, forming second-support features, wherein each second-support feature contacts a respective one of the first-mask features, and wherein a plurality of the second-support features are each separated from an adjacent second-support feature by a gap;
prior to removing the plurality of first-support features and the plurality of second-support features, forming a plurality of second-mask features in the gaps, wherein each of the plurality of second-mask spacers is separated from an adjacent one of the first-mask features by a respective one of the plurality of second-support features;
removing the plurality of first-support features and the plurality of second-support features; and
subsequent to removing the plurality of first-support features and the plurality of second-support features, etching the material to be etched using a pattern of the plurality of first-mask features and the plurality of second-mask features as a mask.
9. The method of claim 8 , wherein:
forming a plurality of first-support features comprises forming a patterned-first-support layer;
forming a plurality of first-mask features comprises forming a plurality of spacers, wherein forming the plurality of spacers comprises forming a patterned-first-top-masking layer;
forming second-support features comprises forming a patterned-second-support layer;
forming a plurality of second-mask features comprises forming a patterned-second-top-masking layer which fills the gaps; and
wherein etching the material to be etched comprises etching a layer to be etched using the pattern of the patterned-first-top-masking layer and the pattern of the patterned-second-top-masking layer as the mask.
10. The method of claim 8 , further comprising forming an etch stop over the material to be etched, wherein the plurality of first-mask features and the plurality of second-mask features are formed on the etch stop, and wherein etching the material to be etched comprises patterning the etch stop using the pattern of the plurality of first-mask features and the plurality of second-mask features, wherein etching the material to be etched comprises using the patterned etch stop as a mask.
11. The method of claim 8 , wherein:
the plurality of first-support features are formed to a first width;
the plurality of first-mask features are formed to a second width which is about the same as the first width;
the plurality of second-support features are formed to a third width which is about the same as the first width; and
the gaps are formed to a fourth width which is about the same as the first width.
12. The method of claim 8 , wherein forming the plurality of first-mask features comprises forming a conformal mask layer and anisotropically etching the conformal mask layer to form spacers.
13. The method of claim 8 , wherein forming the second-support features comprises forming a conformal support layer and anisotropically etching the conformal support layer.
14. The method of claim 8 , wherein forming the plurality of second-mask features comprises:
depositing a blanket mask layer into each of the gaps, over the plurality of first-support features, over the plurality of first-mask features, and over the plurality of second-support features; and
removing the blanket mask layer from over the plurality of first-support features, from over the plurality of first-mask features, and from over the plurality of second-support features.
15. The method of claim 8 , wherein the plurality of first-mask features and the plurality of second-mask features comprise top-mask features, and further comprising:
forming a mask material over the material to be etched;
etching the mask material using the pattern of the top-mask features to transfer the pattern into the mask material; and
trim etching the mask material,
wherein etching the material to be etched using a pattern of the plurality of first-mask features and the plurality of second-mask features comprises etching the material to be etched using the trimmed mask material as a pattern.
16. The method of claim 8 , wherein the material to be etched comprises a semiconductor material.
17. The method of claim 8 , wherein the material to be etched comprises an etch stop material.
18. The method of claim 17 , wherein the etch stop material comprises one of an amorphous silicon and a low silane oxide.
19. The method of claim 8 , wherein the material to be etched comprises a layer of silicon nitride.
20. The method of claim 8 , wherein the plurality of first-support features comprise carbon, the plurality of first-mask features comprise tetraethyl orthosilicate (TEOS), the plurality of second-support features comprise a polymer formed using a gas modulated etch (GMODE) process, and the plurality of second-mask features comprise a silicon-containing polymer.