Reagent for enhancing generation of chemical species

Abstract

A reagent that enhances acid generation of a photoacid generator and composition containing such reagent is disclosed.

Claims

1. A composition comprising: a reagent and a precursor, wherein the reagent enhances the generation of a chemical species from the Precursor; wherein the reagent generates an intermediate by a first exposure using a light the wavelength of which is shorter than or equal to 15 nm; wherein a product is formed from the intermediate by a first elimination and a second elimination; wherein the product is excited by a second exposure using a light of which wavelength is longer than or equal to 300 nm; wherein the reagent transmutes into the product acting as a photosensitizer or acts as an acid generation enhancer; and wherein the reagent has a moiety represented by chemical Formula (I): ##STR00005## where: each of M1 and M2 in chemical Formula (I) is a carbon atom; at least one of A, B, and C in chemical Formula (I) is hydrogen and the rest of A, B, and C in chemical Formula (I) is aryl; at least one of D and E in chemical Formula (I) is hydrogen and the rest of D and E in chemical Formula (I) is an aryl group; and F is selected from the group consisting of an organosilyl group, an organogermyl group, and an organotin group.

2. The composition of claim 1, wherein at least one of the aryl groups has at least one electron-donating group.

3. A method for manufacturing a device, the method comprising: applying a solution of the composition of claim 1 to a substrate such that a coating film containing the composition is formed on the substrate; exposing the coating film to at least one of a film electromagnetic ray and a first particle ray such that a first portion of the coating film is irradiated with the at least one of the first electromagnetic ray and the first particle ray while a second portion of the coating film is not irradiated with the at least one of the first electromagnetic ray and the first particle ray; and exposing the coating film to at least one of a second electromagnetic ray and a second particle ray.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) In the drawings, which illustrate what is currently considered to be the best mode for carrying out the disclosure:

(2) FIG. 1 shows fabrication processes of a device, such as an integrated circuit (IC), using photoresist including an AGE.

DETAILED DESCRIPTION

(3) The disclosure is further described with the aid of the following illustrative Examples.

EXPERIMENTAL PROCEDURES

Synthesis of 1,1,2-tris(4-methoxyphenyl) ethene

(4) 3.14 g of triphenylphosphine is dissolved in 10 mL of toluene. 2.00 g of 4-methoxybenzyl bromide is dissolved in 10 mL of toluene and the solution of 4-methoxybenzyl bromide is added dropwise to the triphenylphosphine solution through the top of the condenser.

(5) The mixture will warm up and a solid will precipitate. The mixture is stirred for 14 hours and the solid is removed by the filtration. Triphenyl (4-methoxyphenylmethyl) phosphonium bromide is washed with hexane.

(6) Triphenyl (4-methoxyphenylmethyl) phosphonium bromide is dissolved in a minimum amount of water in a round bottom flask. An equal amount of toluene is added to the water as the water is poured. 2 drops of phenolphthalein solution is added into the flask. 2.5 M NaOH is added to bring the mixture to the endpoint. The toluene layer is collected and dried. 4-4-methoxybenzylidene (triphenyl) phosphorane is obtained by evaporating toluene on a rotary evaporator.

(7) 0.50 g of 4,4′-dimethoxybenzophenone is placed into a 50-mL round bottom flask equipped with a stir bar. 20 mL of dichloromethane is added and stirred for 10 minutes in an ice bath. 0.8 g of the phosphorane is slowly added. After the addition, the mixture is stirred for another 5 hours and then warmed to room temperature. 1,1,2-Tris(4-methoxyphenyl) ethene is obtained by evaporating the dichloromethane.

Synthesis of 1,1,2-tris(4-methoxyphenyl)-2-triethylsilyl-ethane (Example)

(8) Hydrated chloroplatinic acid (1 g) is dissolved in 2.5 ml of glacial acetic acid. The solution is diluted with 3.6 ml of water and then heated to 70 degrees Celsius. Dicyanopentadiene (1 ml) is added and the mixture is stirred for 24 hours at room temperature. The crude product is filtered and recrystallized twice from THF. It yields 0.4 g of dicyclopentadienyl platinum (II) chloride (DPPC).

(9) In a three-necked flask, 0.2 g of Triethylhydrosilane and 0.2 g of 1,1,2-Tris(4-methoxyphenyl) ethane is dissolved in dry toluene under the protection of nitrogen. DPPC in dichloromethane is added to the mixture. The mixture is heated to reflux 50 hours. The mixture is added to methanol and the precipitate is collected. 0.08 g of 1,1,2-tris(4-methoxyphenyl)-2-triethylsilyl-ethane is obtained by drying the precipitate.

(10) Synthesis of Resin A

(11) A solution containing 5.0 g of alpha-methacryloyloxy-gamma-butylolactone, 6.03 g of 2-methyladamantane-2-methacrylate, and 4.34 g of 3-hydroxyadamantane-1-methacrylate, 0.51 g of dimethyl-2,2′-azobis(2-methylpropionate), and 26.1 g of tetrahydrofuran is prepared. The prepared solution is added for 4 hours to 20.0 g of tetrahydrofuran placed in flask with stirring and boiling. After the addition of the prepared solution, the mixture is heated to reflux for 2 hours and cooled to room temperature. Addition of the mixture by drops to a mixed liquid containing 160 g of hexane and 18 g of tetrahydrofuran with vigorous stirring precipitates the copolymer. The copolymer is isolated by filtration. Purification of the copolymer is carried out by vacuum drying following two washings by 70 g of hexane and, thereby 8.5 g of white powder of the copolymer is obtained.

(12) ##STR00002##

(13) Preparation of Samples for Evaluation (Evaluation Samples)

(14) Evaluation Sample 1 is prepared by dissolving 300 mg of resin A, 36.7 mg of 4,4′-di-(t-butyphenyl)iodonium nonafluorobutanesulfonate as a photoacid generator, and 15.0 mg of coumarin 6 as an indicator in 2000 mg of cyclohexanone.

(15) Evaluation Sample 2 is prepared by dissolving 6.0 mg of Example 1, 300 mg of resin A, 36.7 mg of 4,4′-di-(t-butyphenyl)iodonium nonafluorobutanesulfonate as a photoacid generator, and 15.0 mg of coumarin 6 as an indicator in 2000 mg of cyclohexanone.

(16) Evaluation of Efficiency of Acid Generation

(17) Each of coating films is formed on 4-inch quartz wafers by spin-coating of Evaluation Samples 1 and 2. Each of the coating films is exposed to electron beams of which volumes are 0, 10, 20, 30, and 40 microC/cm.sup.2 output by an electron beam lithography apparatus. Subsequent to the electron-beam exposures, the efficiencies for each of the coating films is obtained by plotting absorbances at 534 nm, which are assigned to quantities of protonated coumarin 6 generated by the respective volumes of electron beams.

(18) Table 1 shows the relative acid-generation efficiencies for the Evaluation Samples 1 and 2. In Table 1, the acid-generation efficiency for Evaluation Sample 1 is used as a benchmark. As shown in Table 1, the acid-generation efficiency is improved by the addition of Example 1. In other words, Example 1 functions as an Acid Generation Enhancer (AGE).

(19) TABLE-US-00001 TABLE 1 The relative acid-generation efficiencies for Samples 1 and 2. Relative acid-generation efficiency Evaluation 1.0 Sample 1 Evaluation 1.3 Sample 2

(20) As understood from the results, a reactive intermediate having reducing character is considered to enhance the efficiency of acid generation.

(21) Evaluation of Sensitivity

(22) Before applying Evaluation Sample 2 to an Si wafer, hexamethyldisilazane (HMDS, Tokyo Chemical Industry) is spin-coated at 2000 rpm for 20 seconds on the surface of the Si wafer and baked at 110 degrees Celsius for 1 minute. Then, the Evaluation Sample 2 is spin-coated on the surface of the Si wafer that has been treated with HMDS at 4000 rpm for 20 seconds to form a coating film.

(23) The prebake of the coating film is performed at 110 degrees Celsius for 60 seconds. Then, the coating film of the Evaluation Sample 2 is exposed to electron beam (EB) output from an EB radiation source. After the EB exposure, an irradiation of the coating film with a UV light is carried out at an ambient condition. After the UV light exposure, a post-exposure-bake (PEB) is carried out at 100 degrees Celsius for 60 seconds. The coating film is developed with NMD-3 (tetra-methyl ammonium hydroxide 2.38%, Tokyo Ohka Kogyo) for 60 seconds at 25 degrees Celsius and rinsed with deionized water for 10 seconds. The thickness of the coating film measured using film thickness measurement tool is approximately 150 nm.

(24) A sensitivity (E.sub.0 sensitivity) is evaluated by measuring the doses to form a pattern constituted by 2-micrometer lines where the thickness of the coating film is not zero and 2-micrometer spaces where the thickness of the coating film is zero using 30 keV electron beam lithography (EBL) system JSM-6500F (JEOL, beam current: 12.5 pA, <1E-4 Pa) with Beam Draw (Tokyo Technology) and the UV exposures using FL-6BL (bright line is mainly from 320 nm to 380 nm, Toshiba).

(25) Even if the UV exposure is carried out without a mask, 2-micrometer spaces are formed in the parts of the coating film that have been exposed to the EB source. This indicates that a product functioning as a photosensitizer for the UV light is generated in the parts exposed to the EB irradiation because the PAGs and the PAG moiety used for the evaluation exhibit little absorbance in a range from 320 nm to 380 nm.

(26) TABLE-US-00002 TABLE 2 The doses for E.sub.0 light by an EB and UV exposure for Evaluation Sample 2 Total dose for E.sub.0 EB dose UV dose [μC/cm.sup.2] [mJ/cm.sup.2] Evaluation 23 0 Sample 2 15 500 5 2000

(27) Table 2 shows the dose sizes corresponding to E.sub.0 sensitivities measured for the Evaluation Sample 2 containing Example 1. Table 2 indicates that the doses of the EB exposure decreases with increase of the doses of the UV light exposure.

(28) A diarylmethyl radical is formed from Example 1 of Evaluation Sample 2 by the EB exposure and the diarylmethyl radical is oxidized to form a corresponding ethene through an elimination of triethyl silyl group. The ethane, 1,1,2-tris(4-methoxyphenyl) ethane (TA), can be excited by the UV light and function as sensitizer to enhance acid generation of the PAG. Typically, such ethane can be excited by a UV light of which wavelength is equal to or longer than 300 nm.

(29) Further photoreaction of 1,1,2-tris(4-methoxyphenyl) ethene (TA) forms a corresponding dihydrophenanthrene (TMDHP), which is to be oxidized easily in the presence of oxygen or oxidizer to form a corresponding phenanthrene (TMPH). The phenanthrene derivative can also be used as photosensitizer. In other words, an irradiation of a longer-wavelength light can be carried out in the atmosphere.

(30) ##STR00003## ##STR00004##

(31) FIG. 1 shows fabrication processes of a device, such as an integrated circuit (IC), using a photoresist including Example 1 as AGE obtained by the processes by the above procedures.

(32) A silicon wafer is provided. The surface of the silicon wafer is oxidized by heating the silicon wafer in the presence of oxygen gas.

(33) A solution of a chemically amplified composition (CAR) including the AGE, resin A, and a PAG is applied to the surface of an Si wafer by spin-coating to form a coating film. The coating film is prebaked.

(34) An irradiation of the coating film with a EUV light (or an electron beam) is carried out after prebake of the Si wafer.

(35) After the EUV irradiation of the coating film, an irradiation of the coating film with a light of which wavelength is equal to or longer than 300 nm is carried out. Such light can excite an ethene derivative generated from the AGE.

(36) Development of the coating film is performed after the prebake. The coating film and the silicon wafer are exposed to plasma. After that, the remaining film is removed.

(37) An electronic device such as integrated circuit is fabricated utilizing the processes shown in FIG. 1. The deterioration of the device due to the irradiation with a light is suppressed, compared to existing photoresists since times for irradiation of the coating film is shortened.