PHOTOSENSITIVE COMPOUND, PHOTOACID GENERATOR AND RESIST COMPOSITION CONTAINING THE PHOTOSENSITIVE COMPOUND, AND METHOD FOR MANUFACTURING DEVICE USING THE RESIST COMPOSITION

Abstract

A photosensitive compound which can be suitably used for a resist composition having superior sensitivity with respect to light of short wavelength such as KrF and the like, especially to extreme ultraviolet or electron beam, superior resolution and depth of focus in lithography, and can suppress LER (line edge roughness) in fine pattern, a resist composition using the photosensitive compound, and a manufacturing method of a device is provided. A photosensitive compound including a divalent Te atom is provided.

Claims

1. A photoacid generator comprising a photosensitive compound containing a divalent Te atom.

2. The photoacid generator of claim 1, wherein the photosensitive compound comprises: a skeleton selected from the group consisting of an onium salt skeleton, a diazomethane skeleton, an imide skeleton and an oxime skeleton; and the skeleton comprises a Te atom containing group represented by the following formula (1);
*TeR.sup.1 (1) where in the formula (1), each of R.sup.1 independently represents either one of a substituent group selected from the group consisting of: a linear, branched, or cyclic hydrocarbon group having 1 to 20 carbon atoms; and an aryl group having 5 to 20 carbon atoms; a part of or all of hydrogen atoms of the hydrocarbon group and the aryl group can be substituted by a substituent; when the hydrocarbon group includes a methylene group, a group including a divalent hetero atom can be included in place of at least one methylene group; the aryl group can include a hetero atom in place of at least one carbon atom in a cyclic structure; and * represents a bonding portion with the skeleton.

3. The photoacid generator of claim 1, wherein the photosensitive compound is represented by the following formula (2); ##STR00031## where in the formula (2), Y represents an atom selected from the group consisting of an iodine atom, a sulfur atom, a selenium atom, and a tellurium atom; when Y is the iodine atom, n is 2; when Y is either one selected from the group consisting of the sulfur atom, the selenium atom, and the tellurium atom, n is 3; R.sup.2 is selected independently from each other from the same candidates for the R.sup.1, and R.sup.2 contains the Te atom containing group as a substituent group in place of at least one hydrogen atom; two or more of R.sup.2 can be bonded to each other to form a ring structure with Y, the ring structure can include a hetero atom; and X.sup. represents an anion.

4. (canceled)

5. A resist composition comprising the photoacid generator of claim 1.

6. The resist composition of claim 5, further comprising an acid-reactive compound.

7. The resist composition of claim 5, further comprising a second photoacid generator.

8. The resist composition of claim 6, wherein the acid-reactive compound is at least either one selected from the group consisting of a compound including a protecting group to be deprotected by acid, a compound including a polymerizing group to polymerize by acid, and a cross-linking agent having cross-link function by acid.

9. A method for manufacturing a device comprising: forming a resist film on a substrate by using the resist composition of claim 8; exposing the resist film carried out by using electron beam or extreme ultraviolet; and forming a resist pattern by developing the exposed resist film.

10. The method for manufacturing of claim 9, wherein the exposing the resist film is carried out by using electron beam or extreme ultraviolet.

11. The photoacid generator of claim 2, wherein the onium salt skeleton has a cation atom selected from the group consisting of an iodine atom, a sulfur atom, a selenium atom, and a tellurium atom; and the imide skeleton is represented by the following formula (3): ##STR00032## where in the formula (3), at least one of R.sup.b and R.sup.c includes the Te atom containing group in the formula (1); R.sup.b represents a group selected from the group consisting of: an alkyl group having 1 to 8 carbon atoms; an alkenyl group having 2 to 8 carbon atoms; an alkoxyalkyl group having 1 to 8 carbon atoms; and an aryl group; a part of or all of hydrogen atoms of R.sup.b can be substituted with a substituent group; R.sup.c represents a group selected from the group consisting of: an arylene group having 6 to 10 carbon atoms; an alkylene group having 1 to 6 carbon atoms; and an alkenylene group having 2 to 6 carbon atoms; and a part of or all of hydrogen atoms of R.sup.c can be substituted with a substituent group.

Description

EXAMPLES

[0179] Hereinafter, some of the embodiments of the present invention will be explained with reference to Examples, however, the present invention shall not be limited to these Examples.

<Synthesis of Tellurium Containing Sulfonium Salt 1>

Synthesis Example 1

Synthesis of Tellurium Containing Sulfide

[0180] A reactor vessel containing magnesium (0.64 g) and THF is heated to 40 to 50 C., followed by dropwise addition of a THF solution of 2-bromo dibenzothiophene (5.79 g), thereby preparing a Grignard reagent. Subsequently, a THF solution of diphenyl ditelluride (8.19 g) is added in a dropwise manner, and general after-treatment is performed after 1 to 3 hours of reaction. Purification is performed by silica gel column chromatography (n-hexane 100%) to obtain the tellurium containing sulfide (3.14 g).

##STR00019##

Synthesis Example 2

Synthesis of Tellurium Containing Sulfoxide

[0181] The tellurium containing sulfide obtained in Synthesis Example 1 (1.16 g), MCPBA (0.76 g), and dichloromethane (5.78 g) are mixed and allowed to react at 25 C. for 1 to 3 hours. General after-treatment is performed, and then purification is performed by silica gel column chromatography (methanol/dichloromethane=20/80) to obtain the tellurium containing sulfoxide (0.60 g).

##STR00020##

Synthesis Example 3

Synthesis of Tellurium Containing Sulfonium Chloride Salt

[0182] The tellurium containing sulfoxide obtained in Synthesis Example 2 (2.00 g), THF solution of 1M phenyl magnesium bromide (6.00 g), trimethyl chlorosilane (1.60 g), and THF (36.0 g) are mixed and agitation is performed for 1 hour. General after-treatment is performed, and then purification is performed by silica gel column chromatography (methanol/dichloromethane=10/90) to obtain the tellurium containing sulfonium chloride salt (0.06 g).

##STR00021##

Synthesis Example 4

Synthesis of Tellurium Containing Sulfonium Salt 1

[0183] The tellurium containing sulfonium chloride salt obtained in Synthesis Example 3 (1.62 g), potassium nonafluorobutanesulfonate (1.21 g), dichloromethane (16.2 g), and water (16.2 g) are mixed and agitation is performed for 1 hour. After washing with water, purification is performed by silica gel column chromatography (methanol/dichloromethane=5/95) to obtain the tellurium containing sulfonium salt 1 (1.9 g).

##STR00022##

(tellurium containing sulfonium salt 1)

<Synthesis of Tellurium Containing Sulfonium Salt 2>

Synthesis Example 5

Synthesis of Tellurium Containing Sulfonium Salt 2

[0184] Similar procedure is carried out as Synthesis Example 4 except for using sodium 4-(1-adamantane carbonyloxy) 1,1,2-trifluorobutane-1-sulfonate in place of potassium nonafluorobutanesulfonate.

##STR00023##

<Synthesis of Tellurium Containing Sulfonium Salt 3>

Synthesis Example 6

Synthesis of Tellurium Containing Sulfonium Salt 3

[0185] Similar procedure is carried out as Synthesis Example 4 except for using sodium 4-(3-hydroxy-1-adamantane carbonyloxy) 1,1,2-trifluorobutane-1-sulfonate in place of potassium nonafluorobutanesulfonate.

##STR00024##

<Synthesis of Tellurium Containing Sulfonium Salt 4>

Synthesis Example 7

Synthesis of Tellurium Containing Sulfonium Salt 4

[0186] Similar procedure is carried out as Synthesis Examples 1 to 4 except for using 4-bromophenyl phenylsulfide in place of 2-boromobenzothiophene in Synthesis Example 1 and for using sodium 4-(3-hydroxy-1-adamantane carbonyloxy) 1,1,2-trifluorobutane-1-sulfonate in place of potassium nonafluorobutanesulfonate in Synthesis Example 4.

##STR00025##

<Synthesis of Polymer (A-1)>

Synthesis Example 8

Synthesis of Polymer (A-1)

[0187] Monomers which constitute each of the constituting unit are polymerized by known radical polymerization and the like using azobisisobutyronitrile (AIBN) as the radical initiator, thereby obtaining polymer A-1 shown below (weight average molecular weight: approximately 10000). In the following formula, relations of a=0.4, b=0.4, and c=0.2 are satisfied, however, the monomer ratio of the unit in the polymer of some embodiments of the present invention is not limited to the followings.

##STR00026##

<Synthesis of Polymer (A-2)>

Synthesis Example 9

Synthesis of Polymer (A-2)

[0188] Monomers which constitute each of the constituting unit are polymerized by known radical polymerization and the like using azobisisobutyronitrile (AIBN) as the radical initiator, thereby obtaining polymer A-2 shown below (weight average molecular weight: approximately 10000). In the following formula, relations of a=0.4, b=0.4, and c=0.2 are satisfied, however, the monomer ratio of the unit in the polymer of some embodiments of the present invention is not limited to the followings.

##STR00027##

<Synthesis of Polymer (A-3)>

Synthesis Example 10

Synthesis of Polymer (A-3)

[0189] Monomers which constitute each of the constituting unit are polymerized by known radical polymerization and the like using azobisisobutyronitrile (AIBN) as the radical initiator, thereby obtaining polymer A-3 shown below (weight average molecular weight: approximately 10000). In the following formula, relations of a=0.4, b=0.4, and c=0.2 are satisfied, however, the monomer ratio of the unit in the polymer of some embodiments of the present invention is not limited to the followings.

##STR00028##

Example 1

<Preparation of Resist Composition>

[0190] Either one of polymer (A-1), polymer (A-2), and polymer (A-3) as the base polymer (100 parts by mass), tellurium containing sulfonium salt 1 as the photoacid generator (8 parts by mass), and propylene glycol monomethyl ether acetate as the solvent (1800 parts by mass) are mixed, followed by filtration using a PTFE filter, thereby preparing a resist composition (H-1). Details of the resist composition are shown in Table 1.

Examples 2 to 12

[0191] Either one of the tellurium containing sulfonium salts 2 to 4 synthesized as above are used by the formulation amount shown in Table 1 in place of the tellurium containing sulfonium salt 1 as the photoacid generator, and the rest of the conditions are carried out in a similar manner as Example 1 to obtain the resist compositions (H-2) to (H-12).

Comparative Examples 1 to 12

[0192] Either one of the photoacid generators (B-1) to (B-4) are used by the formulation amount shown in Table 1 in place of the tellurium containing sulfonium salt 1 as the photoacid generator, and the rest of the conditions are carried out in a similar manner as Example 1 to obtain the resist compositions (H-13) to (H-24).

[0193] Here, the photoacid generators (B-1) to (B-4) are shown below.

##STR00029##

TABLE-US-00001 TABLE 1 polymer photoacid generator solvent for- for- for- mulation mulation mulation resist amount amount amount com- (parts by (parts (parts by position type mass) type by mass) mass) Ex. 1 H-1 A-1 100 Te containing 8.0 1800 sulfonium salt 1 Ex. 2 H-2 A-1 100 Te containing 8.7 1800 sulfonium salt 2 Ex. 3 H-3 A-1 100 Te containing 8.9 1800 sulfonium salt 3 Ex. 4 H-4 A-1 100 Te containing 8.7 1800 sulfonium salt 4 Ex. 5 H-5 A-2 100 Te containing 8.0 1800 sulfonium salt 1 Ex. 6 H-6 A-2 100 Te containing 8.7 1800 sulfonium salt 2 Ex. 7 H-7 A-2 100 Te containing 8.9 1800 sulfonium salt 3 Ex. 8 H-8 A-2 100 Te containing 8.7 1800 sulfonium salt 4 Ex. 9 H-9 A-3 100 Te containing 8.0 1800 sulfonium salt 1 Ex. 10 H-10 A-3 100 Te containing 8.7 1800 sulfonium salt 2 Ex. 11 H-11 A-3 100 Te containing 8.9 1800 sulfonium salt 3 Ex. 12 H-12 A-3 100 Te containing 8.7 1800 sulfonium salt 4 Comp. H-13 A-1 100 B-1 5.9 1800 Ex. 1 Comp. H-14 A-1 100 B-2 6.6 1800 Ex. 2 Comp. H-15 A-1 100 B-3 6.8 1800 Ex. 3 Comp. H-16 A-1 100 B-4 6.6 1800 Ex. 4 Comp. H-17 A-2 100 B-1 5.9 1800 Ex. 5 Comp. H-18 A-2 100 B-2 6.6 1800 Ex. 6 Comp. H-19 A-2 100 B-3 6.8 1800 Ex. 7 Comp. H-20 A-2 100 B-4 6.6 1800 Ex. 8 Comp. H-21 A-3 100 B-1 5.9 1800 Ex. 9 Comp. H-22 A-3 100 B-2 6.6 1800 Ex. 10 Comp. H-23 A-3 100 B-3 6.8 1800 Ex. 11 Comp. H-24 A-3 100 B-4 6.6 1800 Ex. 12

<Evaluation>

[0194] Each of the resist composition is spin coated on a silicon wafer using a spin coater, followed by pre-baking for 60 seconds at 110 C. on a hot plate, thereby obtaining a coating film having a film thickness of 150 nm. A mask is used so that a line pattern of 90 nm can be obtained, and the coating film is exposed by an ArF excimer laser, followed by post-baking for 90 seconds at 110 C. Then, developing is carried out for 60 seconds using a 2.38 mass % aqueous tetramethyl ammonium hydroxide, followed by rinsing with purified water for 30 seconds, thereby obtaining a pattern-formed substrate.

[0195] Resolution, depth of focus, and line edge roughness of Comparative Example 1 is taken as the standard, and sensitivity, resolution, depth of focus and line edge roughness of Examples 1 to 12 and Comparative Examples 2 to 12 are evaluated by the following criteria. Here, scanning electron microscope is used for the measurement of the resist pattern. [0196] Excellent: improvement by 10% or more compared with Comparative Example 1 observed [0197] Good: improvement by 5% or more and less than 10% compared with Comparative Example 1 observed [0198] Poor: improvement by less than 5% compared with Comparative Example 1 observed

(Resolution)

[0199] Resolution shows a width of line pattern (nm) which can be resolved by the minimum exposure amount to reproduce a line pattern of 90 nm. That is, resolution shows a marginal resolving ability. Regarding resolution, the smaller the value, the better resolution.

(Depth of Focus)

[0200] The position of focus is moved up and down, and exposure is performed by minimum exposure amount to reproduce a line pattern of 90 nm, followed by post baking (PEB) and development. The depth of focus shows the range of focus which allows to reproduce the line pattern of 90 nm. The larger the range of focus, the smaller the pattern dimension change with respect to the change in depth of focus, which is favorable.

(Line Edge Roughness: LER)

[0201] With the line pattern of 90 nm obtained by minimum exposure amount to reproduce a line pattern of 90 nm, distance from the standard line where the edge is supposed to exist was measured for 50 points within the range of 2.5 m edge in the longitudinal direction of the line pattern. Then, standard deviation () was obtained from the measurement result, and the tripled value thereof (3) was calculated as LER. When the value is smaller, the roughness becomes smaller and allows achievement of uniform pattern edge, which would be a favorable characteristics.

TABLE-US-00002 TABLE 2 line edge resolution depth of focus roughness Ex. 1 Excellent Excellent Good Ex. 2 Excellent Excellent Excellent Ex. 3 Excellent Excellent Excellent Ex. 4 Excellent Excellent Excellent Ex. 5 Excellent Excellent Good Ex. 6 Excellent Excellent Excellent Ex. 7 Excellent Excellent Excellent Ex. 8 Excellent Excellent Excellent Ex. 9 Excellent Excellent Good Ex. 10 Excellent Excellent Excellent Ex. 11 Excellent Excellent Excellent Ex. 12 Excellent Excellent Excellent Comp. Ex. 1 Comp. Ex. 2 Poor Poor Poor Comp. Ex. 3 Poor Poor Poor Comp. Ex. 4 Poor Poor Poor Comp. Ex. 5 Poor Poor Poor Comp. Ex. 6 Poor Poor Poor Comp. Ex. 7 Poor Poor Poor Comp. Ex. 8 Poor Poor Poor Comp. Ex. 9 Poor Poor Poor Comp. Ex. 10 Poor Poor Poor Comp. Ex. 11 Poor Poor Poor Comp. Ex. 12 Poor Poor Poor

Example 13

Evaluation of Sensitivity

<Preparation of Resist Composition>

[0202] Polymer (A-1) as the base polymer (100 parts by mass), trifluoromethanesulfonate=triphenylsulfonium represented by formula (B-5) as the photoacid generator, tellurium containing sulfonium salt 1, and propylene glycol monomethyl ether acetate as the solvent (3000 parts by mass) are mixed, followed by filtration using a PTFE filter, thereby preparing a resist composition (H-25). Details of the resist composition are shown in Table 3.

##STR00030##

Example 14

[0203] Trifluoromethanesulfonate=triphenylsulfonium as the photoacid generator and tellurium containing sulfonium salt 1 are used by the formulation amount shown in Table 3, and the rest of the conditions are carried out in a similar manner as Example 13 to obtain the resist composition (H-26).

Comparative Example 13

[0204] A similar procedure as Example 13 is carried out except that tellurium containing sulfonium salt is not added, thereby obtaining the resist composition (H-27). Here, in Examples 13 and 14 and Comparative Example 13, the total molar amount of photoacid generator and tellurium containing sulfonium salt 1 used are the same.

TABLE-US-00003 TABLE 3 Te containing photoacid sulfonium 1 polymer generator salt solvent for- for- for- for- mulation mulation mulation mulation resist amount amount amount amount com- (parts by (parts by (parts by (parts by position type mass) mass) mass) mass) Ex. 13 H-25 A-1 100 5.13 1.55 3000 Ex. 14 H-26 A-1 100 4.40 2.72 3000 Comp. Ex. 13 H-27 A-1 100 5.87 3000

<Evaluation of Sensitivity>

[0205] Each of the resist composition is spin coated on a silicon wafer using a spin coater, followed by pre-baking for 60 seconds at 110 C. on a hot plate, thereby obtaining a coating film having a film thickness of 50 nm. The coating film is exposed by EUV, followed by post-baking for 60 seconds at 110 C. Then, developing is carried out for 60 seconds using a 2.38 mass % aqueous tetramethyl ammonium hydroxide, followed by rinsing with purified water for 30 seconds, thereby obtaining a pattern-formed substrate.

[0206] The exposure amount which provides no residual film as the formed resist film is evaluated as the sensitivity.

TABLE-US-00004 TABLE 4 sensitivity (mJ/cm.sup.2) Ex. 13 16 Ex. 14 8 Comp. Ex. 13 20

[0207] In Examples 1 to 12 which use the tellurium containing sulfonium salt of some of the embodiments of the present invention, characteristics of resolution, depth of focus, and LER are superior. On the other hand, in Comparative Examples 1 to 12 which do not use the tellurium containing sulfonium salt, further improvement is required for the characteristics of resolution, depth of focus, and LER.

[0208] Further, as shown Examples 13, 14 and Comparative Example 13, in the evaluation of sensitivity, it can be understood that sensitivity can be enhanced by adding a suitable amount of tellurium containing sulfonium salt to photoacid generator. Here, when either one of the photoacid generators (B-1) to (B-4) is used in combination with the tellurium containing sulfonium salt in place of photoacid generator represented by formula (B-5) as the photoacid generator, a similar result as Examples 13 and 14 can be achieved.

[0209] From the afore-mentioned results, the photosensitive compound according to one of the embodiments of the present invention have superior sensitivity, resolution, and depth of focus in lithography, and has an effect to suppress LER in fine pattern.