Patternable low dielectric constant materials and their use in ULSI interconnection
View Patent ↗The present invention relates to ultra-large scale integrated (ULSI) interconnect structures, and more particularly to patternable low dielectric constant (low-k) materials suitable for use in ULSI interconnect structures. The patternable low-k dielectrics disclosed herein are functionalized polymers that having one or more acid-sensitive imageable functional groups.
1. A method of forming a patterned interconnect structure comprising:
(a) providing a structure including a cap layer atop a substrate;
(b) applying a patternable low-k composition comprising a functionalized polymer having one or more acid-sensitive imageable groups, wherein said functional polymer has a dielectric constant of less than 3.9 and said functionalized polymer is a caged silsesquioxane polymer including combinations thereof having the formula:
wherein each occurrence of R 1 is independently one or more acidic functional groups for base solubility; each occurrence of R 2 independently comprises at least one acid-sensitive imageable functional group for crosslinking; R 1 is not equal to R 2 ; m and n represent the number of repeating units; m is an integer; and n is zero or an integer greater than zero, wherein said acid-sensitive imageable functional group for crosslinking is selected from a linear or branched alkyl that is substituted with at least one of —OH, epoxide, and —F; a cycloalkyl which is substituted wit at least one of —OH, epoxide, and —F; a cyclo aromatic that is substituted with at least one of —OH, epoxide, and —F; or an arene that is substituted with at least one of —OH, epoxide, and —F onto said cap layer;
(c) forming via and/or line patterns in said paternable low-k composition;
(d) curing said patternable low-k composition to convert said composition into a patternable low-k material; and
(e) filling said via/or line patterns with at least a conductive material.
2. The method of claim 1 wherein each occurrence of R 1 independently comprises a linear or branched alkyl which is substituted with at least one of OH, —C(O)OH, and F; a cycloalkyl which is substituted with at least one of —OH, —C(O)OH and —F; an aromatic which is substituted with at least one of —OH, —C(O)OH, and —F; an arene that is substituted with at least one of OH, —C(O)OH and —F; or an acrylic that is substituted with at least one of —OH, —C(O)OH and —F.
3. The method of claim 1 wherein each occurrence of R 1 independently is one of the formula moieties:
4. The method of claim 1 wherein each occurrence of R 2 independently is one or more acid-sensitive functional groups for crosslinking.
5. The method of claim 1 wherein each occurrence of R 2 independently comprises one of the following:
wherein R 10 is any R 2 group and t is from 1 to 20.
6. The method of claim 1 wherein R 2 further comprises an acid-sensitive protecting group.
7. The method of claim 6 wherein said acid-sensitive protecting group comprises cyclic or branched aliphatic carbonyls, tertiary esters, or tertiary ethers.
8. The method of claim 7 wherein said R 2 is one of the following moieties:
wherein R 5 and R 6 cyclic or branched aliphatic carbonyls, tertiary esters, or tertiary ethers.
9. The method of claim 1 wherein said patternable low k composition further comprises a photosensitive acid generator and a solvent.
10. The method of claim 9 further comprising an acid sensitive crosslinking agent.