Hardmask

Abstract

This invention provides a composition containing an organometallic compound having a chromophore moiety in the metal polymer backbone which allows a wider range of n/k values such that substrate reflectivity can be controlled under various conditions.

Claims

1. A method comprising: providing a substrate; coating a film of the composition comprising: an organometallic compound of the formula ##STR00009## wherein R.sup.2(C.sub.1-C.sub.20)hydrocarbyl; M.sup.1 is a Group 3 to Group 14 metal; G=R.sup.3.sub.b-Ch-R.sup.3.sub.b or Ch(OM.sup.1L.sup.1.sub.mOR.sup.2).sub.c; Ch=a chromophore moiety; R.sup.3 is a divalent linking group having from 1 to 12 carbon atoms; R.sup.4H, R.sup.2 or M(L.sup.1).sub.mOR.sup.2; L.sup.1 is a ligand; m refers to the number of ligands and is an integer from 1-4; a=an integer from 1 to 20; each b is independently an integer from 0 to 25; c=1 or 2; and an organic solvent on a surface of the substrate; curing the film under conditions sufficient to form a metal hardmask layer comprising the chromophore moiety; disposing a layer of a photoresist on the cured metal hardmask layer; and exposing the photoresist by to patterned radiation to form an image.

2. The method of claim 1 wherein M.sup.1 is chosen from titanium, zirconium, hafnium, tungsten, tantalum, molybdenum, vanadium, indium, germanium, gallium, thallium, and aluminum.

3. The method of claim 1 wherein each L.sup.1 is chosen from (C.sub.1-C.sub.20)alkoxy, (C.sub.2-C.sub.20)carboxyl, beta-diketonates, beta-hydroxyketonates, beta-ketoesters, beta-diketiminates, amindinates, guanidinates, or beta-hydroxyiminates.

4. The method of claim 1 wherein the chromophore moiety comprises one or more of an aromatic ring or an isocyanurate.

5. The method of claim 4 wherein the aromatic ring is chosen from phenyl, naphthyl, anthracenyl, or phenanthryl.

6. The method of claim 1 wherein the chromophore is an isocyanurate.

7. The method of claim 1 wherein the composition further comprises a surface treating polymer having a surface energy of 20 to 40 erg/cm.sup.2 and comprising a surface treating moiety chosen from hydroxyl, protected hydroxyl, protected carboxyl, or mixtures thereof.

8. The method of claim 1 wherein R.sup.3 comprises one or more atoms selected from the group consisting of oxygen, nitrogen, and sulfur.

9. The method of claim 1 wherein R.sup.3 is selected from the group consisting of (C.sub.2-C.sub.12)alkylene-O and (C.sub.2-C.sub.12)alkylidene-O.

10. The method of claim 1 wherein G is chosen from Ch, Ch-R.sup.3.sub.b, R.sup.a.sub.b-Ch, or Ch(OM.sup.1L.sup.1.sub.mOR.sup.2).sub.c.

11. The method of claim 1 wherein the chromophore moiety is substituted with one or more substituents selected from the group consisting of (C.sub.1-C.sub.6)alkyl, cyano, halo, nitro and SO.sub.3Y, where YH, ammonium or an alkali metal ion.

Description

EXAMPLE 1

(1) An organometallic oligomer comprising a chromophore moiety was prepared as follows. To a flask equipped with a Dean-Stark trap were added Ti(OR).sub.2(acac).sub.2 (R=n-butyl or isoporopyl, Tyzor AA-105, available from DuPont) and 0.33 equivalents of tris-(2-hydroxyethyl)isocyanurate (TCEIC). This mixture was heated at 120-130 C., stirred for 1-2 days and the distillate collected. The mixture was then cooled and quenched in heptane (500 mL). The precipitated solid was dried in vacuum to give 13 g of desired product, Polymer A, shown in Equation 1, below.

(2) ##STR00005##

EXAMPLE 2

(3) The procedure of Example 1 is repeated except that zirconium bis(acetylacetone)-bis(n-butoxide) (or Zr(acac).sub.2(OBu).sub.2) is reacted with 0.33 equivalents of TCEIC, to provide Polymer B.

EXAMPLE 3

(4) The procedure of Example 1 is repeated except that hafnium bis(acetylacetone)-bis(n-butoxide) (or Hf(acac).sub.2(OBu).sub.2) is reacted with 0.33 equivalents of TCEIC to provide Polymer C.

COMPARATIVE EXAMPLE 4

(5) The procedure of Example 1 was repeated except that TTCEIC was replaced with approximately 1 equivalent of diethylene glycol, to provide the Comparative Polymer 1, as shown in Equation 2.

(6) ##STR00006##

EXAMPLE 5

(7) Polymer A and Comparative Polymer were individually formulated in a mixture of 2-methyl-1-butanol and gamma-butyrrolactone (95/5 weight ratio) at 3.5 wt % solids and filtered through 0.2 m poly(tetrafluoroethylene) (PTFE) syringe filter. The obtained solutions were coated on a silicon wafer having a layer of AR26 Antireflectant (available from Dow Electronic Materials) at 1500 rpm and baked at 280 C. for 60 seconds. Next, a layer of a commercial photoresist (either 193 nm or 248 nm resist, available from Dow Electronic Materials) was spin coated on the surface of both Polymer A and Comparative Polymer. The n/k values of the obtained polymer films were measured using VUV-VASE (J. A. Woolam Co. Inc.), and substrate reflectivity was calculated using Prolith software from KLA-Tencor Co. under the condition indicated in Table 1.

(8) TABLE-US-00001 TABLE 1 Film stack Resist FT = 95 nm Polymer to be FT = 0~100 nm, n/k varied evaluated AR 26 bottom FT = 80 nm, n(193) = 1.695, layer k(193) = 0.628 Si Illumination ArF immersion exposure at 1.35NA, dipole-35Y, o/i = 0.98/0.86, X-polarization 39 nm 1:1 L/S, binary mask

(9) Table 2 summarizes the n/k values and minimum reflectivity. By incorporating TCEIC, n-value was increased from 1.69 to 1.85, and the minimum reflectivity was reduced from 3.3% to 2.1%.

(10) TABLE-US-00002 TABLE 2 193 nm Photoresist 248 nm Photoresist n k R % (FT) n k Polymer A 1.846 0.536 4.6% (19 nm) 1.849 0.271 Comparative 1.695 0.502 5.0% (36 nm) 1.913 0.606 Polymer

EXAMPLE 6

(11) A 5 L three-necked flask was equipped with a reflux condenser, a mechanical stirrer and an inlet adapter. To this reactor was added 400 g of Hf(OBu).sub.4 (0.85 mol) and 2.3 L of anhydrous tetrahydrofuran (THF), and this mixture was stirred vigorously using a mechanical stirrer. To this stirred mixture was added a solution of 700 mL of anhydrous THF and pentane-2,4-dione (170 g, 1.7 mol) over 6 hours via a Scilog pump. The reaction mixture was stirred overnight at room temperature. The reaction mixture was then reduced to dryness under vacuum. 800 mL of anhydrous ethyl acetate was added and the mixture was stirred vigorously at room temperature for several hours. This solution was filtered through a fine frit to remove any insoluble material. The solvent was removed from the filtrate under vacuum and a pale white solid (Hf(acac).sub.2(OBu).sub.2) was obtained (288.5 g, 65% yield), which was used without further purification.

COMPARATIVE EXAMPLE 7

(12) A 2 L three-necked flask was equipped with a reflux condenser, a mechanical stirrer and a thermocouple. To this flask was added anhydrous ethyl acetate (1.3 L) solution of Hf(acac).sub.2(OBu).sub.2 from Example 6 (288.5 g, 0.55 mol), and ethylene diglycol (55.5 g, 0.52 mol), and the reaction mixture was refluxed at 80 C. for 16-18 hours. Next, the solution was cooled to 25 C. and then filtered through a fine frit to remove any precipitated solid (94 g). The filtrate was reduced in volume and then quenched into 10 volume of heptane with stirring overnight. The solid was collected and washed with heptane three times (31 L). The white powder was dried under strong vacuum for 2 hours, yielding 135 g of a white polymer, Comparative Polymer 2, as shown in Equation 3.

(13) ##STR00007##

EXAMPLE 8

(14) To a 500 mL three-necked flask was equipped with a mechanical stirrer, condenser, inlet stopper, and a gas inlet was added 50 g of Hf(OBu).sub.4 (0.106 moles) and 150 mL of anhydrous THF under a blanket of N.sub.2. A solution of pentane-2,4-dione (2 equivalents) and 50 mL of anhydrous THF was added via a Scilog pump over 6 hours, and the reaction mixture stirred over night. The THF was removed under reduced pressure and the resulting white solid was triturated with 400 mL of anhydrous ethyl acetate for 2-3 hours to dissolve all solids. The reaction mixture was then transferred to a 500 mL three-necked flask and 1,4-dimethanol benzene was added. The reaction mixture was heated to reflux while removing 100 mL ethyl acetate, and held at reflux for 18 hours. The reaction mixture was then cooled to room temperature and then concentrated to 100-150 mL and then quenched into 10 volume of heptanes yielding a free flowing solid which coagulated into a gummy solid. This was allowed to stand in heptanes while the gummy material was manipulated. The gummy material eventually became free flowing and was left stirring overnight. The solids were collected, washed with heptanes, and then vacuum dried at 40 C. overnight to yield 41 g of product, Polymer D, as shown in Equation 4.

(15) ##STR00008##

EXAMPLE 9

(16) The procedure of Example 5 was repeated except that Polymer D, Comparative Polymer 2, and a 1:1 blend of Polymer D and Comparative Polymer 2 were used. The data are shown in Table 3, which clearly shows that Polymer D itself, and in combination with Comparative Polymer 2, provides reduced reflectivity.

(17) TABLE-US-00003 TABLE 3 193 nm 248 nm n k R % (FT) n k Comparative Polymer 2 1.912 0.074 1.46% 1.689 0.014 (17 nm) Polymer D 1.819 0.469 3.41% 1.795 0.127 (24 nm) Blend of Comparative 1.862 0.298 0.48% 1.771 0.089 Polymer 2 and Polymer D (24 nm)