Methods for making semiconductor structures having high-speed areas and high-density areas
View Patent ↗Methods for making a semiconductor structure are discussed. The methods include forming openings in a high-density area and a high-speed area, and forming a metallization layer simultaneously into the high-density area and the high-speed area. The metallization layer includes a combination of substances and compounds that reduce vertical resistance, reduce horizontal resistance, and inhibit cross-diffusion.
1. A method for making a semiconductor structure in a substrate having an array area and a periphery area, the method comprising:
forming a transistor in the array area and a transistor in the periphery area;
forming a stopping layer over the transistors in the array area and the periphery area, the stopping layer having a characteristic to stop an etching process when consumed by the etching process;
forming over the stopping layer a nonconductive layer;
forming openings by etching the nonconductive layer and the stopping layer, the openings exposing a polycrystalline silicon layer of the transistor in the array area and the transistor in the periphery area; and
forming a metallization layer by filling the openings with conductive substances and compounds, the metallization layer forming a local interconnect layer for the transistor in the array area and forming a strapping layer for the transistor in the periphery area.
2. The method of claim 1 , wherein forming openings includes forming openings by a self-aligned contact (SAC) etching technique.
3. The method of claim 1 , wherein forming openings includes forming openings on gate structures in the high-density area to form contacts and forming openings on gate structures in the high-speed area so as to strap.
4. The method of claim 1 , wherein forming a metallization layer includes forming a metallization layer that includes over-gate routings in the periphery area, slot holes in the periphery area, and contact holes in the periphery area.
5. The method of claim 1 , wherein forming a metallization layer includes forming a silicide compound, forming a barrier layer, and forming a conductive layer.
6. A method for making a semiconductor structure in a semiconductor substrate having an array and a periphery, the method comprising:
depositing a nonconductive stack over a gate and source/drain of a memory cell in the array and over a gate of a transistor in the periphery, the nonconductive stack including a stopping layer and a nonconductive layer;
photolithographing to mark portions of the array and the periphery, the portions of the array including portions that are superjacent to the gate and source/drain of the memory cell in the array, the portions of the periphery includes portions that are superjacent to the gate of the transistor;
removing the portions of the array and the periphery that are marked to expose a polycrystalline silicon layer of the gate and source/drain of the memory cell in the array and to expose the gate of the transistor in the periphery; and
depositing simultaneously local interconnect materials into portions of the array and the periphery that were removed by the act of removing.
7. The method of claim 6 , wherein photolithographing includes photolithographing to mark portions of an array and a periphery, wherein a portion of the array includes local interconnect, and wherein a portion of the periphery includes gate straps, contact holes, contact slots, and local routing.
8. The method of claim 7 , wherein removing includes etching away the revealed portions of the array so as to open up selected areas of the portion of the array and the portion of the periphery, wherein etching includes etching using a dry etch technique.
9. The method of claim 8 , wherein depositing includes depositing simultaneously local interconnect materials, wherein the local interconnect materials include a combination of a substance to form a silicide, a barrier substance, and a substance to form a main conductive layer.
10. The method of claim 9 , wherein depositing includes depositing simultaneously local interconnect materials, wherein the local interconnect materials includes titanium, titanium nitride, and tungsten.
11. A method for making a semiconductor structure in a substrate having an array and a periphery, comprising:
photolithographing to mask portions of gates in the array and the periphery, the gates including a polycrystalline silicon layer;
dry-etching portions of the gates that are masked;
depositing over the gates a nonconductive stack having a stopping layer;
photolithographing portions of the array and the periphery that include the gates;
dry-etching the portions of the array and the periphery until stopped by the stopping layer to expose a portion of the polycrystalline layer of at least one of the gates in the array and the periphery; and
depositing simultaneously local interconnect materials into portions of the array and the periphery that are etched by the act of dry-etching.
12. The method of claim 11 , further comprising depositing a group of materials to form gate structures, wherein the group of materials include a combination of a gate oxide material, polycrystalline silicon, a conductive material, and a cap dielectric material, wherein the conductive material include a conductor material andlor a barrier material, and wherein the act of depositing a group of materials to form gate structures occurs before the act of photolithographing to expose gate structures in an array and a periphery.
13. The method of claim 12 , wherein photolithographing to mask portions of gates in an array and a periphery includes photolithographing to exhume contact in a portion of gate structures in the array and to open the portion of gate structures in the periphery so as to strap a conductive material to the portion of the gate structures in the periphery.
14. The method of claim 13 , wherein dry-etching includes dry-etching a portion of the conductive material and the cap dielectric material.
15. The method of claim 14 , further comprising stripping a resist that is formed by photolithographing, forming spacers, depositing a dielectric liner, and depositing borophosphosilicate glass.
16. The method of claim 15 , wherein dry-etching the portions of the array and the periphery that are exposed includes etching to remove a portion of the borophosphosilicate glass and a portion of the dielectric liner.
17. The method of claim 16 , further comprising depositing a substance to form a silicide compound, a barrier compound, and a conductive substance.
18. The method of claim 17 , further comprising planarizing using a chemical-mechanical planarization technique to planarize the conductive substance.
19. A method for forming a routing in a periphery area of a semiconductor structure, comprising:
forming from a nonconductive stack a first trench that superjacently abuts along a substantial length of a first gate stack in the periphery and further forming a second trench that superjacently abuts a second gate stack in the periphery, the first gate stack including a gate oxide layer, a polycrystalline silicon layer formed on the gate oxide layer, a conductive layer formed on the polycrystalline layer, and a gate cap layer formed on the conductive layer and second gate stack including a polycrystalline silicon layer, the nonconductive stack including a stopping layer that stops an etching process once etched away to define the bottom of the trenches and expose at least a portion of the polycrystalline silicon layer of the second gate stack; and
filling the trenches with a conductive stack to form the routing over the first gate stack and a conductive strap for the second gate stack, the first trench having a large cross-sectional area to decrease a horizontal resistance of the routing.
20. The method of claim 19 , further comprising forming the nonconductive stack by depositing the stopping layer over the gate stack and a dielectric layer over the stopping layer.
21. The method of claim 20 , wherein forming the trench includes photolithographing the nonconductive stack and etching the nonconductive stack until the act of etching is stopped when the stopping layer is consumed by the act of etching.
22. The method of claim 21 , wherein etching includes dry etching the nonconductive stack.
23. The method of claim 22 , wherein the conductive stack includes titanium.
24. A method for making semiconductor structures on a substrate having an array area and a periphery area, comprising:
forming from a nonconductive stack a number of openings to expose a number of semiconductor structures in the array area and in the periphery area, the nonconductive stack including a stopping layer to stop an etching process once etched away to define the bottom of each opening and expose a portion of a polycrystalline silicon layer for at least one of the semiconductor structures in the array area and in the periphery area; and
filling the number of openings with a conductive stack having the characteristic to reduce a vertical resistance of each semiconductor structure and a horizontal resistance of each semiconductor structure so as to increase the performance of each semiconductor structure.