MONOMER, POLYMER, POSITIVE RESIST COMPOSITION, AND PATTERNING PROCESS

Abstract

A polymer comprising recurring units derived from a polymerizable monomer having two structures of hydroxyphenyl methacrylate having a hydroxy group substituted with an acid labile group is used as base resin in a positive resist composition, especially chemically amplified positive resist composition. The resist composition forms a resist film which is processed by lithography into a pattern of good profile having a high resolution, minimal edge roughness, and etch resistance.

Claims

1. A monomer having the formula (1): ##STR00173## wherein R.sup.1 is hydrogen or methyl, R.sup.2 is hydrogen or a straight, branched or cyclic C.sub.1-C.sub.15 monovalent hydrocarbon group in which any constituent CH.sub.2 may be replaced by O, C(O), C(O)O or OC(O), R.sup.3 is each independently hydrogen, cyano, nitro, or a straight, branched or cyclic C.sub.1-C.sub.6 monovalent hydrocarbon group in which any constituent CH.sub.2 may be replaced by O, C(O), C(O)O or OC(O), R.sup.4 is each independently hydrogen or an acid labile group, X.sup.1 is a single bond, a C.sub.1-C.sub.12 linking group having an ester moiety, ether moiety or lactone ring, a phenylene group or naphthylene group, and m is an integer of 1 to 4.

2. The monomer of claim 1 wherein the acid labile group is t-butyl, t-pentyl, methylcyclopentyl, ethylcyclopentyl, methylcyclohexyl, ethylcyclohexyl, methyladamantyl, ethyladamantyl, t-butoxycarbonyl, t-pentyloxycarbonyl, or CR.sup.5R.sup.6OR.sup.7, wherein R.sup.5 and R.sup.6 are each independently hydrogen or a straight or branched C.sub.1-C.sub.4 alkyl group, R.sup.7 is a straight, branched or cyclic alkyl group or straight, branched or cyclic C.sub.2-C.sub.12 alkenyl group.

3. A polymer comprising recurring units (a) having the formula (A): ##STR00174## wherein R.sup.1 is hydrogen or methyl, R.sup.2 is hydrogen or a straight, branched or cyclic C.sub.1-C.sub.15 monovalent hydrocarbon group in which any constituent CH.sub.2 may be replaced by O, C(O), C(O)O or OC(O), R.sup.3 is each independently hydrogen, cyano, nitro, or a straight, branched or cyclic C.sub.1-C.sub.6 monovalent hydrocarbon group in which any constituent CH.sub.2 may be replaced by O, C(O), C(O)Oor OC(O), R.sup.4 is each independently hydrogen or an acid labile group, X.sup.1 is a single bond, a C.sub.1-C.sub.12 linking group having an ester moiety, ether moiety or lactone ring, a phenylene group or naphthylene group, m is an integer of 1 to 4, and a is a positive number in the range: 0<a1.0.

4. The polymer of claim 3 wherein the acid labile group is t-butyl, t-pentyl, methylcyclopentyl, ethylcyclopentyl, methylcyclohexyl, ethylcyclohexyl, methyladamantyl, ethyladamantyl, t-butoxycarbonyl, t-pentyloxycarbonyl, or CR.sup.5R.sup.6OR.sup.7, wherein R.sup.5 and R.sup.6 are each independently hydrogen or a straight or branched C.sub.1-C.sub.4 alkyl group, R.sup.1 is a straight, branched or cyclic C.sub.1-C.sub.12 alkyl group or straight, branched or cyclic C.sub.2-C.sub.12 alkenyl group.

5. The polymer of claim 3, further comprising recurring units (b) containing an adhesive group selected from the group consisting of hydroxyl, carboxyl, lactone ring, carbonate, thiocarbonate, carbonyl, cyclic acetal, ether, ester, sulfonic acid ester, cyano, amide, and OC(O)-G- wherein G is sulfur or NH.

6. The polymer of claim 5 wherein the recurring unit (b) is a unit containing a phenolic hydroxyl group.

7. The polymer of claim 6 wherein the recurring unit containing a phenolic hydroxyl group is selected from recurring units (b1) to (b9) having the formulae (B1) to (B9): ##STR00175## ##STR00176## wherein R.sup.8 is hydrogen or methyl, R.sup.9 is C.sub.1-C.sub.4 alkyl, C(O)R.sup.9a, OC(O)R.sup.9a, C(O)OR.sup.9a, cyano or nitro group, X.sup.11 and X.sup.22 are each independently a single bond or C(O)OR.sup.10a, X.sup.33 and X.sup.44 each are C(O)OR.sup.10a, R.sup.9a is C.sub.1-C.sub.4 alkyl or C.sub.2-C.sub.4 alkenyl, R.sup.10a is a single bond or a straight, branched or cyclic C.sub.1-C.sub.10 alkylene group, Y.sup.1 and Y.sup.2 are each independently methylene or ethylene, Z is methylene, oxygen or sulfur, p is 1 or 2, b1 to b9 are numbers in the range: 0b1<1.0, 0b2<1.0, 0b3<1.0, 0b4<1.0, 0b5<1.0, 0b6<1.0, 0b7<1.0, 0b8<1.0, 0b9<1.0, and 0<b1+b2+b3+b4+b5+b6+b7+b8+b9<1.0.

8. The polymer of claim 3, further comprising recurring units of at least one type selected from recurring units (c1) to (c5) having the formulae (C1) to (C5): ##STR00177## wherein R.sup.11 to R.sup.15 are each independently hydrogen, C.sub.1-C.sub.30 alkyl, C.sub.1-C.sub.30 alkyl in which one or more or all carbon-bonded hydrogen atoms are substituted by halogen, C.sub.1-C.sub.5 alkoxy, C.sub.1-C.sub.8 alkanoyl, C.sub.2-C.sub.8 alkoxycarbonyl, C.sub.6-C.sub.10 aryl, halogen, or 1,1,1,3,3,3-hexafluoro-2-propanol group, Z is methylene, oxygen or sulfur, c1 to c5 are numbers in the range: 0c1 <1.0, 0c2<1.0, 0c3<1.0, 0c4<1.0, 0c5<1.0, and 0<c1+c2+c3+c4+c5<1.0.

9. The polymer of claim 3, further comprising recurring units of at least one type selected from sulfonium salt-containing recurring units (d1) to (d3) having the formulae (D1) to (D3): ##STR00178## wherein R.sup.112 is hydrogen or methyl, R.sup.113 is a single bond, phenylene, OR.sup.122, or C(O)Z.sup.22R.sup.122, Z.sup.22 is oxygen or NH, R.sup.122 is a straight, branched or cyclic C.sub.1-C.sub.6 alkylene, C.sub.2-C.sub.6 alkenylene or phenylene group, which may contain a carbonyl, ester, ether or hydroxyl moiety, L is a single bond or Z.sup.33C(O)O, Z.sup.33 is a straight, branched or cyclic C.sub.1-C.sub.20 divalent hydrocarbon group which may be substituted with a heteroatom, Z.sup.11 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, OR.sup.123, or C(O)Z.sup.44R.sup.123, Z.sup.44 is oxygen or NH, R.sup.123 is a straight, branched or cyclic C.sub.1-C.sub.6 alkylene, C.sub.2-C.sub.6 alkenylene or phenylene group, which may contain a carbonyl, ester, ether or hydroxyl moiety, M.sup. is a non-nucleophilic counter ion, R.sup.114, R.sup.115, R.sup.116, R.sup.117, R.sup.118, R.sup.119, R.sup.120, and R.sup.121 are each independently a straight, branched or cyclic C.sub.1-C.sub.20 monovalent hydrocarbon group which may contain a heteroatom, d1, d2 and d3 are numbers in the range: 0d10.5, 0d20.5, 0d30.5, and 0<d1+d2+d30.5.

10. A positive resist composition comprising the polymer of claim 3, and an organic solvent.

11. The resist composition of claim 10, further comprising a photoacid generator.

12. The resist composition of claim 10, further comprising a dissolution regulator.

13. The resist composition of claim 10, further comprising a basic compound and/or surfactant.

14. A pattern forming process comprising the steps of coating the positive resist composition of claim 10 onto a substrate, baking the coating to form a resist film, exposing the resist film to high-energy radiation, and developing the exposed resist film in a developer.

Description

EXAMPLE

[0167] Examples and Comparative Examples are given below for further illustrating the invention, but they should not be construed as limiting the invention thereto. All parts (pbw) are by weight. Mw is a weight average molecular weight as measured versus polystyrene standards by GPC using tetrahydrofuran (THF) solvent. IR spectroscopy was measured by NICOLET 6700 (Thermo Fisher Scientific Inc.) and .sup.1H-NMR spectroscopy by ECA-600 (JEOL Ltd.).

Synthesis of Monomers

Example 1-1

[0168] ##STR00128##

Example 1-1-1

Synthesis of Alcohol 1

[0169] In nitrogen atmosphere, a solution of Chloride 1 (203.1 g) and 1,2-dibromoethane (1.2 g) in THF (183 g) was added dropwise to a suspension of magnesium (28.1 g) in THF (30 g) at a temperature of 65-80 C. Stirring was continued at the temperature for 12 hours, obtaining Grignard reagent 1. The reaction solution was cooled to room temperature, to which a solution of ethyl formate (37.0 g) in THF (240 g) was added dropwise at a temperature of 20-40 C. Stirring was continued at the temperature for 3 hours. A 15 wt % ammonium chloride aqueous solution (1,300 g) was added dropwise to the reaction solution to quench the reaction. This was followed by ordinary aqueous workup and recrystallization from an ethyl acetate/n-hexane mixture, obtaining Alcohol 1 (138 g, yield 84%). It was analyzed by .sup.1H-NMR spectroscopy.

[0170] .sup.1H-NMR (600 MHz in DMSO-d.sub.6):

[0171] =7.24 (4H, d), 6.89 (4H, d), 5.73 (1H, d), 5.61 (1H, d), 1.24 (18H, s) ppm

Example 1-1-2

Synthesis of Monomer 1

[0172] Alcohol 1 (137 g), triethylamine (59.4 g) and 4-(dimethylamino)pyridine (1.5 g) were added to toluene (200 g). To the solution which was heated at an internal temperature of 40-50 C., Esterifying agent 1 (74.3 g) was added dropwise. The solution was stirred at 50 C. for 2 hours. The reaction solution was ice cooled, to which a saturated sodium hydrogencarbonate aqueous solution was added dropwise to quench the reaction. This was followed by ordinary aqueous workup and recrystallization from an ethyl acetate/methanol mixture, obtaining Monomer 1 (146 g, yield 87%). It was analyzed by IR and .sup.1H-NMR spectroscopy.

[0173] IR (D-ATR); =2976, 2930, 1709, 1637, 1605, 1505, 1365, 1290, 1238, 1174, 1157, 1107, 1014, 897, 859 cm.sup.1

[0174] .sup.1H-NMR (600 MHz in DMSO-d.sub.6):

[0175] 7.28 (4H, d), 6.93 (4H, d), 6.80 (1H, s), 6.17 (1H, s), 5.71 (1H, m), 1.92 (3H, s), 1.26 (18H, s) ppm

Example 1-2

[0176] ##STR00129##

[0177] In nitrogen atmosphere, 10 wt % hydrochloric acid (6.0 g) was added dropwise to a solution of Monomer 1 (10.0 g) in acetone (40 g) at a temperature of 20-30 C. Stirring was continued at the temperature for 4 hours. Ethyl acetate (50 g) was added to the reaction solution. This was followed by ordinary aqueous workup and recrystallization from an ethyl acetate/n-hexane mixture, obtaining Monomer 2 (3.3 g, yield 46%).

Example 1-3

[0178] ##STR00130##

Example 1-3-1

Synthesis of Alcohol 2

[0179] Alcohol 2 was obtained by the same procedure as in Example 1-1-1 aside from using Chloride 2 instead of Chloride 1. Yield 81%.

Example 1-3-2

Synthesis of Monomer 3

[0180] Monomer 3 was obtained by the same procedure as in Example 1-1-2 aside from using Alcohol 2 instead of Alcohol 1. Yield 86%.

Example 1-4

[0181] ##STR00131##

Example 1-4-1

Synthesis of Alcohol 3

[0182] Alcohol 3 was obtained by the same procedure as in Example 1-1-1 aside from using Chloride 3 instead of Chloride 1. Yield 81%. It was analyzed by .sup.1H-NMR spectroscopy.

[0183] .sup.1H-NMR (600 MHz in DMSO-d.sub.6):

[0184] =7.22 (4H, app d), 6.89 (4H, app d), 5.72 (1H, d), 5.59 (1H, d), 1.59-1.78 (8H, m), 1.36-1.47 (10H, m), 1.25-1.33 (2H, m), 1.17 (6H, s) ppm

Example 1-4-2

Synthesis of Monomer 4

[0185] Monomer 4 was obtained by the same procedure as in Example 1-1-2 aside from using Alcohol 3 instead of Alcohol 1. Yield 80%. It was analyzed by IR and .sup.1H-NMR spectroscopy.

[0186] IR (D-ATR): =2932, 2859, 1719, 1637, 1607, 1506, 1447, 1375, 1290, 1227, 1153, 1106, 1011, 964, 895, 848 cm.sup.1

[0187] .sup.1H-NMR (600 MHz in DMSO-d.sub.6):

[0188] =7.27 (4H, d), 6.93 (4H, d), 6.79 (1H, s), 6.17 (1H, s), 5.73 (1H, s), 1.91 (3H, s), 1.73-1.79 (4H, m), 1.57-1.64 (4H, m), 1.36-1.46 (10H, m), 1.25-1.32 (2H, m), 1.18 (6H, s) ppm

Example 1-5

[0189] ##STR00132##

Example 1-5-1

Synthesis of Alcohol 4

[0190] Alcohol 4 was obtained by the same procedure as in Example 1-1-1 aside from using Chloride 4 instead of Chloride 1. Yield 82%.

Example 1-5-2

Synthesis of Monomer 5

[0191] Monomer 5 was obtained by the same procedure as in Example 1-1-2 aside from using Alcohol 4 instead of Alcohol 1. Yield 85%.

Example 1-6

[0192] ##STR00133##

Example 1-6-1

Synthesis of Alcohol 5

[0193] Alcohol 5 was obtained by the same procedure as in Example 1-1-1 aside from using Chloride 5 instead of Chloride 1. Yield 87%.

Example 1-6-2

Synthesis of Monomer 6

[0194] Monomer 6 was obtained by the same procedure as in Example 1-1-2 aside from using Alcohol 5 instead of Alcohol 1. Yield 79%.

Example 1-7

[0195] ##STR00134##

Example 1-7-1

Synthesis of Ketone 1

[0196] In nitrogen atmosphere, Hydroxy-ketone 1 (10.0 g) and triethylamine (13.2 g) were mixed with acetonitrile (50 ml). Below 20 C., Protecting agent 1 (13.7 g) was added dropwise. Stirring was continued at room temperature for 4 hours. Water (30 ml) was added to the reaction solution to quench the reaction. This was followed by ordinary aqueous workup. The product was purified by silica gel column chromatography, obtaining Ketone 1 (16.6 g, yield 92%).

Example 1-7-2

Synthesis of Alcohol 6

[0197] A solution of Ketone 1 (16.0 g) in THF (15 g) was added dropwise to a suspension of sodium borohydride (1.3 g) in water (10 g) and methanol (30 g) at a temperature of 20-40 C. Stirring was continued at 40 C. for 2 hours. This was followed by ordinary aqueous workup. The product was purified by silica gel column chromatography, obtaining Alcohol 6 (13.7 g, yield 85%). It was analyzed by .sup.1H-NMR spectroscopy.

[0198] .sup.1H-NMR (600 MHz in DMSO-d.sub.6)%

[0199] =7.24 (4H, app d), 6.95 (4H, app d), 5.69 (1H, d), 5.59 (1H, d), 4.90 (2H, d), 3.24 (6H, s), 2.00 (2H, sept), 0.91 (12H, t) ppm

Example 1-7-3

Synthesis of Monomer 7

[0200] Monomer 7 was obtained by the same procedure as in Example 1-1-2 aside from using Alcohol 6 instead of Alcohol 1. Yield 86%. It was analyzed by IR and .sup.1H-NMR spectroscopy.

[0201] IR (D-ATR): =2962, 2929, 2875, 1717, 1637, 1610, 1509, 1471, 1391, 1291, 1239, 1206, 1154, 1096, 1004, 952, 901, 831 cm.sup.1

[0202] .sup.1H-NMR (600 MHz in DMSO-d.sub.6):

[0203] =7.31 (4H, app d), 7.00 (4H, app d), 6.77 (1H, s), 6.17 (1H, s), 5.73 (1H, m), 4.94 (2H, d), 3.24 (6H, d), 2.01 (2H, sept), 1.92 (3H, s), 0.93 (12H, t) ppm

Example 1-8

[0204] ##STR00135##

[0205] Monomer 8 was obtained by the same procedure as in Example 1-1-2 aside from using Esterifying agent 2 instead of Esterifying agent 1. Yield 81%.

Example 1-9

[0206] ##STR00136##

Example 1-9-1

Synthesis of Ketone 2

[0207] In nitrogen atmosphere, Hydroxy-ketone 1 (21.4 g) and triethylamine (10.1 g) were mixed with acetonitrile (200 ml). Below 20 C., Protecting agent 2 (10.0 g) was added dropwise. Stirring was continued at room temperature for 4 hours. Water (100 ml) was added to the reaction solution to quench the reaction. This was followed by ordinary workup. The product was purified by silica gel column chromatography, obtaining Ketone 2 (23.8 g, yield 63%).

Example 1-9-2

Synthesis of Alcohol 7

[0208] A solution of Ketone 2 (18.0 g) in THF (30 g) was added dropwise to a suspension of sodium borohydride (1.1 g) in water (10 g) and methanol (30 g) at a temperature of 20-40 C. Stirring was continued at 40 C. for 2 hours. This was followed by ordinary aqueous workup. The product was purified by silica gel column chromatography, obtaining Alcohol 7 (15.8 g, yield 83%).

Example 1-9-3

Synthesis of Monomer 9

[0209] Monomer 9 was obtained by the same procedure as in Example 1-1-2 aside from using Alcohol 7 instead of Alcohol 1. Yield 81%.

Example 1-10

[0210] ##STR00137##

[0211] Monomer 10 was obtained by the same procedure as in Example 1-1-2 aside from using Esterifying agent 3 instead of Esterifying agent 1. Yield 76%.

Example 1-11

[0212] ##STR00138##

[0213] Monomer 11 was obtained by the same procedure as in Example 1-2 aside from using Monomer 10 instead of Monomer 1. Yield 43%.

Example 1-12

[0214] ##STR00139##

[0215] Monomer 12 was obtained by the same procedure as in Example 1-4-2 aside from using Esterifying agent 4 instead of Esterifying agent 1. Yield 82%.

Example 1-13

[0216] ##STR00140##

[0217] Monomer 13 was obtained by the same procedure as in Example 1-1-2 aside from using Esterifying agent 5 instead of Esterifying agent 1. Yield 74%.

Example 1-14

[0218] ##STR00141##

[0219] Monomer 14 was obtained by the same procedure as in Example 1-1-2 aside from using Esterifying agent 6 instead of Esterifying agent 1. Yield 70%.

Example 1-15

[0220] ##STR00142##

Example 1-15-1

Synthesis of Alcohol 8

[0221] Alcohol 8 was obtained by the same procedure as in Example 1-1-1 aside from using ethyl acetate instead of ethyl formate. Yield 73%.

Example 1-15-2

Synthesis of Monomer 15

[0222] Monomer 15 was obtained by the same procedure as in Example 1-1-2 aside from using Alcohol 8 instead of Alcohol 1 and Esterifying agent 7 instead of Esterifying agent 1. Yield 86%.

[0223] Monomers 1 to 15 synthesized in Examples 1-1 to 1-15 are shown below by their structure.

##STR00143## ##STR00144## ##STR00145## ##STR00146## ##STR00147##

Synthesis of polymers

Example 2-1

Synthesis of Resist Polymer 1

[0224] In nitrogen atmosphere, Monomer 1 (24.0 g), 4-hydroxyphenyl methacrylate (16.0 g), dimethyl 2,2-azobisisobutyrate (0.35 g), and 4-mercaptoethanol (0.36 g) were dissolved in methyl ethyl ketone (55.7 g). With stirring at 80 C. in nitrogen atmosphere, the solution was added dropwise to methyl ethyl ketone (18.6 g) over 4 hours. At the end of dropwise addition, stirring was continued at 80 C. for 2 hours. The polymerization solution was cooled to room temperature and added dropwise to n-hexane (400 g). A solid precipitate was filtered and vacuum dried at 50 C. for 20 hours, obtaining a polymer in white powder solid form. The polymer, designated Resist Polymer 1, had the structure shown below. Amount 36.4 g, yield 91%.

Resist Polymer 1

[0225] (a=0.40, b=0.60, Mw=9,100)

##STR00148##

Examples 2-2 to 2-20 and Comparative Examples 1-1 to 1-3

Synthesis of Resist Polymers 2 to 20 and Comparative Polymers 1 to 3

[0226] Resist Polymers 2 to 20 and Comparative Polymers 1 to 3 were prepared by the same procedure as in Example 2-1 except that the type and amount of monomers were changed. A ratio of monomers incorporated is on a molar basis.

Resist Polymer 2

[0227] (a=0.40, b=0.60, Mw=8,300)

##STR00149##

Resist Polymer 3

[0228] (a=0.40, b=0.60, Mw=9,300)

##STR00150##

Resist Polymer 4

[0229] (a=0.40, b=0.60, Mw=9,800)

##STR00151##

Resist Polymer 5

[0230] (a=0.35, b=0.65, Mw=9,300)

##STR00152##

Resist Polymer 6

[0231] (a=0.35, b=0.35, c=0.30, Mw=8,600)

##STR00153##

Resist Polymer 7

[0232] (a=0.35, b=0.35, c=0.30, Mw=8,500)

##STR00154##

Resist Polymer 8

[0233] (a=0.35, b=0.35, c=0.30, Mw=8,500)

##STR00155##

Resist Polymer 9

[0234] (a=0.20, b=0.20, c=0.30, d=0.30, Mw=8,600)

##STR00156##

Resist Polymer 10

[0235] (a=0.20, b=0.20, c=0.30, d=0.30, Mw=8,800)

##STR00157##

Resist Polymer 11

[0236] (a=0.20, b=0.20, c=0.30, d=0.30, Mw=8,500)

##STR00158##

Resist Polymer 12

[0237] (a=035, b=0.10, c=0.30, d=0.25, Mw=8,500)

##STR00159##

Resist Polymer 13

[0238] (a=0.30, b=0.20, c=0.40, d=0.10, Mw=10,600)

##STR00160##

Resist Polymer 14

[0239] (a=0.30, b=0.20, c=0.40, d=0.10, Mw=11,100)

##STR00161##

Resist Polymer 15

[0240] (a=0.30, b=0.20, c=0.35, d=0.15, Mw=10,900)

##STR00162##

Resist Polymer 16

[0241] (a=0.30, b=0.55, c=0.15, Mw=10,200)

##STR00163##

Resist Polymer 17

[0242] (a=0.10, b=0.10, c=0.70, d=0.10, Mw=13,000)

##STR00164##

Resist Polymer 18

[0243] (a=0.15, b=0.15, c=0.30, d=0.25, e=0.15, Mw=11,000)

##STR00165##

Resist Polymer 19

[0244] (a=0.15, b=0.15, c=0.30, d=0.25, e=0.15, Mw=12,100)

##STR00166##

Resist Polymer 20

[0245] (a=0.15, b=0.15, c=0.30, d=0.25, e=0.15, Mw=11,700)

##STR00167##

Comparative Polymer 1

[0246] (a=0.40, b=0.60, Mw=6,800)

##STR00168##

Comparative Polymer 2

[0247] (a=0.20, b=0.20, c=0.30, d=0.30, Mw=8,000)

##STR00169##

Comparative Polymer 3

[0248] (a=0.15, b=0.15, c=0.30, d=0.25, e=0.15, Mw=11,300)

##STR00170##

Preparation of Resist Composition

Examples 3-1 to 3-23 and Comparative Examples 2-1 to 2-3

[0249] Positive resist compositions (R-1 to R-23, R-24 to R-26) were prepared by dissolving a polymer (Resist Polymers 1 to 20, Comparative Polymers 1 to 3), a photoacid generator, quencher, and water-repellent polymer in a solvent in accordance with the recipe shown in Table 1, and filtering through a Teflon filter having a pore size of 0.2 m. The solvent contained 0.01 wt % of a surfactant KH-20 (Asahi Glass Co., Ltd.).

[0250] The components in Table 1 are as identified below.

Acid Generators:

[0251] PAG1 to PAG3 of the following structural formulae

##STR00171##

Quenchers: Q-1, Q-2 of the Following Structural Formulae

[0252] ##STR00172##

Organic Solvents:

[0253] propylene glycol monomethyl ether acetate (PGMEA) cyclohexanone (CyH)

TABLE-US-00001 TABLE 1 Acid Resist Resin generator Quencher Solvent composition (pbw) (pbw) (pbw) (pbw) Example 3-1 R-1 Resist Polymer 1 PAG-3 Q-2 PGMEA(1,000) (100) (20.0) (1.4) CyH(2,000) 3-2 R-2 Resist Polymer 2 PAG-3 Q-2 PGMEA(1,000) (100) (20.0) (1.4) CyH(2,000) 3-3 R-3 Resist Polymer 3 PAG-3 Q-2 PGMEA(1,000) (100) (20.0) (1.4) CyH(2,000) 3-4 R-4 Resist Polymer 4 PAG-3 Q-2 PGMEA(1,000) (100) (20.0) (1.4) CyH(2,000) 3-5 R-5 Resist Polymer 5 PAG-3 Q-2 PGMEA(1,000) (100) (20.0) (1.4) CyH(2,000) 3-6 R-6 Resist Polymer 6 PAG-3 Q-2 PGMEA(1,000) (100) (20.0) (1.4) CyH(2,000) 3-7 R-7 Resist Polymer 7 PAG-3 Q-2 PGMEA(1,000) (100) (20.0) (1.4) CyH(2,000) 3-8 R-8 Resist Polymer 8 PAG-3 Q-2 PGMEA(1,000) (100) (20.0) (1.4) CyH(2,000) 3-9 R-9 Resist Polymer 9 PAG-3 Q-2 PGMEA(1,000) (100) (20.0) (1.4) CyH(2,000) 3-10 R-10 Resist Polymer 10 PAG-3 Q-2 PGMEA(1,000) (100) (20.0) (1.4) CyH(2,000) 3-11 R-11 Resist Polymer 11 PAG-3 Q-2 PGMEA(1,000) (100) (20.0) (1.4) CyH(2,000) 3-12 R-12 Resist Polymer 12 PAG-3 Q-2 PGMEA(1,000) (100) (20.0) (1.4) CyH(2,000) 3-13 R-13 Resist Polymer 13 Q-2 PGMEA(1,000) (100) (1.4) CyH(2,000) 3-14 R-14 Resist Polymer 14 Q-2 PGMEA(1,000) (100) (1.4) CyH(2,000) 3-15 R-15 Resist Polymer 15 Q-2 PGMEA(1,000) (100) (1.4) CyH(2,000) 3-16 R-16 Resist Polymer 16 Q-2 PGMEA(1,000) (100) (1.4) CyH(2,000) 3-17 R-17 Resist Polymer 17 Q-2 PGMEA(1,000) (100) (1.4) CyH(2,000) 3-18 R-18 Resist Polymer 18 Q-2 PGMEA(1,000) (100) (1.4) CyH(2,000) 3-19 R-19 Resist Polymer 19 Q-2 PGMEA(1,000) (100) (1.4) CyH(2,000) 3-20 R-20 Resist Polymer 20 Q-2 PGMEA(1,000) (100) (1.4) CyH(2,000) 3-21 R-21 Resist Polymer 6 PAG-1 Q-2 PGMEA(1,000) (100) (15.0) (1.4) CyH(2,000) 3-22 R-22 Resist Polymer 6 PAG-2 Q-2 PGMEA(1,000) (100) (20.0) (1.4) CyH(2,000) 3-23 R-23 Resist Polymer 20 Q-1 PGMEA(1,000) (100) (1.4) CyH(2,000) Comparative 2-1 R-24 Comparative Polymer 1 PAG-3 Q-2 PGMEA(1,000) Example (100) (20.0) (1.4) CyH(2,000) 2-2 R-25 Comparative Polymer 2 PAG-3 Q-2 PGMEA(1,000) (100) (20.0) (1.4) CyH(2,000) 2-3 K-26 Comparative Polymer 3 PAG-3 Q-2 PGMEA(1,000) (100) (20.0) (1.4) CyH(2,000)

EUV Lithography Test

Examples 4-1 to 4-23 and Comparative Examples 3-1 to 3-3

[0254] A silicon-containing undercoat material (SHB-A940 by Shin-Etsu Chemical Co., Ltd.) was coated onto a silicon substrate of diameter 4 inches and heated at 220 C. for 60 seconds to form a resist undercoat of 35 nm thick. The resist composition (R-1 to R-23, R-24 to R-26) was spin coated onto the coated substrate and pre-baked on a hot plate at 110 C. for 60 seconds to form a resist film of 30 nm thick. Using an exposure tool (NA 0.3, Pseudo-PSM mask), the resist film was exposed to EUV.

[0255] Immediately after the exposure, the resist film was baked (PEB) on a hot plate at the temperature shown in Table 2 for 60 seconds and puddle developed in a 2.38 wt % TMAH aqueous solution for 20 seconds to form a positive pattern.

[0256] Resolution is a minimum size at the exposure dose (sensitivity) that provides a 1:1 resolution of a 20-nm line-and-space pattern. The 20-nm L/S pattern was measured for roughness (LWR) under SEM.

[0257] The resist composition is shown in Table 2 together with the sensitivity and resolution of EUV lithography.

TABLE-US-00002 TABLE 2 PEB Resist temp. Sensitivity Resolution LWR composition ( C.) (mJ/cm.sup.2) (nm) (nm) Example 4-1 R-1 85 32 20 3.9 4-2 R-2 75 35 21 3.9 4-3 R-3 85 27 19 3.6 4-4 R-4 90 29 19 3.8 4-5 R-5 85 26 19 3.8 4-6 R-6 85 34 19 3.6 4-7 R-7 30 31 18 3.6 4-8 R-8 70 32 20 3.6 4-9 R-9 75 28 19 3.6 4-10 R-10 75 29 20 3.3 4-11 R-11 70 27 20 3.3 4-12 R-12 80 34 19 3.1 4-13 R-13 80 31 18 2.9 4-14 R-14 80 30 18 2.8 4-15 R-15 80 29 17 3.0 4-16 R-16 80 26 19 3.2 4-17 R-17 85 36 24 3.9 4-18 R-18 75 28 17 3.3 4-19 R-19 75 26 17 3.4 4-20 R-20 75 25 17 3.5 4-21 R-21 85 36 20 3.0 4-22 R-22 85 35 19 3.3 4-23 R-23 75 28 19 3.4 Comparative 3-1 R-24 85 36 25 4.3 Example 3-2 R-25 75 33 28 4.5 3-3 R-26 75 30 23 4.0

EB Writing Test

Examples 5-1 to 5-4 and Comparative Examples 4-1 to 4-3

[0258] Using a coater/developer system Clean Track Mark 5 (Tokyo Electron Ltd.), the positive resist composition (R-1 to R-23, R-24 to R-26) was spin coated onto a silicon substrate of diameter 6 inches and pre-baked on a hot plate at 110 C. for 60 seconds to form a resist film of 100 nm thick. Using a system HL-800D (Hitachi Ltd.) at a HV voltage of 50 kV, the resist film was exposed imagewise to EB in a vacuum chamber.

[0259] Using Clean Track Mark 5, immediately after the exposure, the resist film was baked (PER) on a hot plate at the temperature shown in Table 3 for 60 seconds and puddle developed in a 2.38 wt % TMAH aqueous solution for 30 seconds to form a positive pattern.

[0260] Resolution is a minimum size at the exposure dose (sensitivity) that provides a 1:1 resolution of a 120-nm line-and-space pattern. The 120-nm L/S pattern was measured for roughness (LWR) under SEM.

[0261] The resist composition is shown in Table 3 together with the sensitivity and resolution of EB lithography.

TABLE-US-00003 TABLE 3 PEB Resist temp. Sensitivity Resolution LWR composition ( C.) (C/cm.sup.2) (nm) (nm) Example 5-1 R-1 90 29 80 5.9 5-2 R-10 90 31 75 5.4 5-3 R-17 95 32 70 4.8 5-4 R-20 90 31 65 4.3 Comparative 4-1 R-24 90 29 90 7.2 Example 4-2 R-25 85 30 85 6.9 4-3 R-26 85 27 80 6.6

Dry Etching Test

Examples 6-1 to 6-4 and Comparative Examples 5-1 to 5-2

[0262] Each polymer, 2 g, was thoroughly dissolved in 10 g of cyclohexanone, and passed through a filter having a pore size of 0.2 m, obtaining a polymer solution. The polymer solution was spin coated onto a silicon substrate and baked to form a polymer film of 300 nm thick. Using a dry etching instrument TE-8500P (Tokyo Electron Ltd.), the polymer film was etched with CHF.sub.3/CF.sub.4 gas under the following conditions.

TABLE-US-00004 Chamber pressure 40.0 Pa RF power 1000 W Gap 9 mm CHF.sub.3 gas flow rate 3 ml/min CF.sub.4 gas flow rate 30 ml/min Ar gas flow rate 100 ml/min Time 60 sec

[0263] The difference in polymer film thickness before and after etching was determined, from which an etching rate per minute was computed. The results are shown in Table 4. A smaller value of film thickness difference, i.e., a lower etching rate indicates better etch resistance.

TABLE-US-00005 TABLE 4 CHF.sub.3/CF.sub.4 gas etching Resin rate (nm/mm) Example 6-1 Resist Polymer 1 92 6-2 Resist Polymer 5 90 6-3 Resist Polymer 10 96 6-4 Resist Polymer 17 91 Comparative 5-1 Comparative Polymer 1 96 Example 5-2 Comparative Polymer 2 104

[0264] It is evident from Tables 2 and 3 that the resist compositions using the inventive polymers show satisfactory resolution, sensitivity and edge roughness. These polymers have good dry etch resistance as demonstrated by a smaller difference in film thickness before and after etching in Table 4.

[0265] Japanese Patent Application No. 2015-137416 is incorporated herein by reference.

[0266] Although some preferred embodiments have been described, many modifications and variations may be made thereto in light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described without departing from the scope of the appended claims.