Organic polymeric antireflective coatings deposited by chemical vapor deposition
An improved method for applying organic antireflective coatings to substrate surfaces and the resulting precursor structures are provided. Broadly, the methods comprise chemical vapor depositing (CVD) an antireflective compound on the substrate surface. In one embodiment, the compound is highly strained (e.g., having a strain energy of at least about 10 kcal/mol) and comprises two cyclic moieties joined to one another via a linkage group. The most preferred monomers are [2.2](1,4)-naphthalenophane and [2.2](9,10)-anthracenophane. The CVD processes comprise heating the antireflective compound so as to vaporize it, and then pyrolizing the vaporized compound to form stable diradicals which are subsequently polymerized on a substrate surface in a deposition chamber. The inventive methods are useful for providing highly conformal antireflective coatings on large substrate surfaces having super submicron (0.25 μm or smaller) features.
1. A method of forming a precursor for use in manufacturing integrated circuits comprising the steps of:
providing a quantity of an antireflective compound and a substrate having a surface onto which said compound is to be applied, said antireflective compound having the formula
wherein:
each R is individually selected from the group consisting of alkyl groups; and
each X is individually selected from the group consisting of hydrogen, the halogens, nitro groups, amino groups, acetamido groups, substituted and unsubstituted cyclic and heterocyclic groups, and COR 1 , where R 1 is selected from the group consisting of hydrogen, substituted and unsubstituted phenyl groups, substituted and unsubstituted alkyl groups, cinnamoyl, naphthoyl, acryloyl, methacryloyl, furoyl, and thiophenecarbonyl groups; and
subjecting said antireflective compound to a chemical vapor deposition process so as to deposit said antireflective compound in a layer on said substrate surface, said antireflective compound layer deposited on said substrate surface absorbing at least about 90% of light at a wavelength of from about 150-500 mm.
2. The method of claim 1 , further including the step of applying a photoresist layer to said antireflective compound layer.
3. The method of claim 2 , wherein said antireflective compound layer has a thickness after said depositing step, and said thickness will change by less than about 10% in solvents utilized in said photoresist layer.
4. The method of claim 2 , further including the steps of:
exposing at least a portion of said photoresist layer to activating radiation;
developing said exposed photoresist layer; and
etching said developed photoresist layer to an etching process.
5. The method of claim 1 , wherein at least one of said cyclic moieties is heterocyclic or aromatic.
6. The method of claim 5 , wherein said cyclic moieties are selected from the group consisting of benzene, naphthalene, anthracene, phenanthrene, pyrene, pyridine, pyridazine, pyrimidine, pyrazine, thiazole, isothiazole, oxazole, isooxazole, thiophene, furan, and pyrrole.
7. The method of claim 1 , wherein the strain energy of said antireflective compound is at least about 10 kcal/mol.
8. The method of claim 1 , wherein said substrate comprises a silicon wafer.
9. The method of claim 1 , wherein said chemical vapor deposition process comprises the steps of:
(a) subjecting said antireflective compound to a sufficient temperature and pressure to form said antireflective compound into a vapor;
(b) cleaving the resulting vaporized compound; and
(c) depositing said cleaved compound onto said substrate surface.
10. The method of claim 9 , wherein said subjecting step (a) is carried out at a temperature of from about 35-160° C. and a pressure of from about 2-50 mTorr.
11. The method of claim 9 , wherein said cleaving step (b) comprises breaking a bond between two of the atoms of each R.
12. The method of claim 9 , wherein said cleaving step (b) comprises pyrolizing said antireflective compound.
13. The method of claim 12 , wherein said pyrolizing step comprises heating said antireflective compound to a temperature of from about 580-700° C.
14. The method of claim 9 , wherein said depositing step (c) comprises subjecting said cleaved compound to a temperature of from about 20-25° C.
15. The method of claim 1 , wherein the antireflective compound layer deposited on said substrate surface will be subjected to light of a predetermined wavelength and has a k value of at least about 0.1 at said predetermined wavelength.
16. The method of claim 1 , wherein the antireflective compound layer deposited on said substrate surface has a percent conformality of at least about 85%.
17. The method of claim 1 , wherein said substrate comprises raised features and structure defining contact or via holes, and said subjecting step comprises depositing a quantity of said antireflective compound in a layer on said features and said hole-defining structure.