Disposable pillars for contact information
Sacrificial plugs for forming contacts in integrated circuits, as well as methods of forming connections in integrated circuit arrays are disclosed. Various pattern transfer and etching steps can be used to create densely-packed features and the connections between features. A sacrificial material can be patterned in a continuous zig-zag line pattern that crosses word lines. Planarization can create parallelogram-shaped blocks of material that can overlie active areas to form sacrificial plugs, which can be replaced with conductive material to form contacts.
1. A method comprising:
forming first and second lines, each of the first and second lines extending in a first direction;
forming third, fourth and fifth lines, each of the third, fourth and fifth lines extending in a second direction so that each of the third, fourth and fifth lines crosses over each of the first and second lines, the fourth line intervening between the third and fifth lines such that the third and fourth lines define a first gap there-between and the fourth and fifth lines define a second gap there-between;
filling the first and second gaps with first and second insulating blocks, respectively;
removing at least the fourth line to define a void, the void being surrounded by respective parts of the first and second lines and respective parts of the first and second insulating blocks; and
forming a conductive plug into the void.
2. The method of claim 1 , wherein the removing at least the fourth line is carried out such that the void exposes a part of a semiconductor substrate.
3. The method of claim 2 , wherein the removing at least the fourth line comprises removing the third and fifth lines simultaneously with the fourth line.
4. The method of claim 1 , wherein the forming conductive material comprises depositing a conductive material over the void, the first and second lines, and the first and second insulating blocks, and planarizing the conductive material to expose the first and second lines and the first and second insulating blocks.
5. The method of claim 1 , wherein each of the first and second lines comprises a conductive layer and an insulating layer covering top and side surfaces of the conductive layer.
6. The method of claim 5 , wherein each of the third, fourth, and fifth lines comprises an insulating material, and each of the insulating layer and the first and second insulating blocks is different in material than each of the third, fourth, and fifth lines.
7. The method of claim 6 , wherein each of the insulating layer and the first and second insulating blocks comprises a silicon nitride film.
8. The method of claim 5 , wherein each of the first and second lines is a word line.
9. A method comprising:
forming a plurality of interconnect lines over a semiconductor substrate apart from one another, each of the plurality of interconnect lines extending in a first direction and comprising a conductive layer and an insulating layer covering the conductive layer;
depositing a sacrificial layer over the plurality of interconnect lines;
patterning the sacrificial layer to form a plurality of sacrificial lines apart from one another, each of the plurality of sacrificial lines extending in a second direction to cross over each of the plurality of interconnect lines;
depositing an insulating material over the plurality of interconnect lines and the plurality of sacrificial lines;
planarizing the insulating material to expose each of the plurality of sacrificial lines while keeping the plurality of interconnect lines covered with respective portions of the insulating material;
removing a plurality of the sacrificial material lines to form a plurality of voids, each of the plurality of voids being defined by associated adjacent two of the plurality of interconnect lines and associated adjacent two of the respective portions of the insulating material; and
forming a plurality of conductive plugs in the plurality of voids, respectively.
10. The method of claim 9 , wherein the method further comprises forming a plurality of active areas in the semiconductor substrate, the plurality of active areas being separated from one another by trench isolation, and wherein each of the plurality of interconnect lines is formed to cross over selected one or ones of the plurality of active areas.
11. The method of claim 10 , wherein each of the conductive plugs is in contact with a corresponding one of the plurality of active areas.
12. The method of claim 10 , wherein the plurality of conductive plugs includes a plurality of sets of conductive plugs and each of the plurality of sets of conductive plugs is in electrical contact with a corresponding one of the plurality of active areas.
13. The method of claim 9 , wherein the insulating layer comprises a first material, wherein the insulating material comprises a second material, and wherein the sacrificial layer comprises a third material that is different from each of the first and second materials.
14. The method of claim 13 , wherein the each of the first and second materials comprises silicon nitride.
15. The method of claim 9 , wherein the forming a plurality of conductive plugs comprises depositing a conductive material over the plurality of interconnect lines and the respective portions of the insulating material and planarizing the conductive material to expose upper surfaces of the plurality of interconnect lines and the respective portions of the insulating material.
16. The method of claim 9 , wherein each of the interconnect lines is formed as a word line.
17. A method comprising:
forming a conductive layer over a substrate;
patterning the conductive layer to form a plurality of conductive lines apart from one another, each of the conductive lines being elongated in a first direction;
forming side wall layers on respective side surfaces of the conductive lines to form a plurality of interconnect lines;
forming a pattern over the plurality of interconnect lines and the substrate, the pattern comprising a plurality of sacrificial lines and a plurality of insulating lines that are disposed alternately, each of the plurality of sacrificial lines and the plurality of insulating lines being elongated in a second direction to cross over each of the interconnect lines; and
removing the plurality of sacrificial lines to form a plurality of voids, each of the voids being defined by the side wall layers of associated adjacent two of the plurality of interconnect lines and associated adjacent two of the insulating lines.
18. The method of claim 17 , further comprising forming a plurality of conductive plugs in the plurality of voids, respectively.
19. The method of claim 18 , wherein the method further comprises forming a plurality of active areas in the substrate prior to the forming a conductive layer over a substrate, and wherein each of the plurality of conductive plugs is in electrical contact with an associated one of the plurality of active areas.
20. The method of claim 18 , wherein the method further comprises forming a plurality of active areas in the substrate prior to the forming a conductive layer over a substrate, wherein the plurality of conductive plugs comprises a plurality of sets of conductive plugs, and wherein each of the plurality of sets of conductive plugs is in electrical contact with an associated one of the plurality of active areas.
21. The method of claim 20 , wherein the method further comprises forming a plurality of sets of capacitors, each of the plurality of sets of capacitors being in electrical contact with an associated one of the plurality of active areas.
22. The method of claim 18 , wherein each of the plurality of interconnect lines constitutes a word line.