JPH07168355A - Positive type resist composition - Google Patents

Abstract

PURPOSE:To obtain a positive type resist compsn. excellent in balance of such various properties as resolution, profile, sensitivity, heat resistance and the depth of a focus. CONSTITUTION:This positive type resist compsn. contains a quinonediazido photosensitive agent contg. quinonediazidosulfonic ester of at least one of phenol compds. represented by formula I and an alkalisoluble resin. In the formula I (n) is 1-3 each of R1-R3 is H, alkyl, etc., R4 is alkyl or phenyl, in the case of n=1, R1-R3 are different from one another or R1-R3 are not H and at least one of them is different from the others, each of Q1-Q12 is H, alkyl or phenyl and each of Z1-Z5 is a group represented by formula II [where each of R5-R7 is H, halogen, etc., in the case of n=1, R5-R7 are different from one another or R5-R7 are not H and at least one of them is different from the others, and (p) is 0-1].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive resist composition which is sensitive to radiation such as ultraviolet rays, deep ultraviolet rays including excimer laser, electron rays, ion beams and X-rays.

[0002]

2. Description of the Related Art In recent years, integrated circuits have become finer with higher integration, and submicron pattern formation is required. As a result, there is a demand for a positive resist composition having a better profile, depth of focus, resolution and the like for a positive resist. In particular, in the fabrication of 16 to 64M DRAM, it is necessary to resolve a pattern having a line width of 0.5 μm or less with a good profile and a wide depth of focus.

SPIE vol.1086 Advances in Resis
t Technology and Processing VI (1989) / 363-373
On the page are cresol / formaldehyde novolac resins, as well as 2,3,4-trihydroxybenzophenone, 2,6-bis [(2-hydroxy-3,5-dimethylphenyl) methyl] -4-methylphenol or 2,3.
6-bis [(4-hydroxy-3,5-dimethylphenyl) methyl] -4-methylphenol and naphthoquinone-
Positive resist compositions containing each triester with 2-diazide-5-sulfonic acid are described.
JP-A-2-285351 discloses the following formula

[0004]

[Chemical 4]

[In the formula, R ¹ and R ² are hydrogen and have 1 to 1 carbon atoms.
4 is a linear or branched alkyl group or alkoxy group (provided that R ¹ and R ² do not become hydrogen at the same time), and X is a divalent organic group. ] The group represented by
A photosensitive material obtained by reacting a polyhydroxy compound having at least one in a molecule with 1,2-naphthoquinone-5- (and / or -4-) sulfonyl chloride, and an alkali-soluble novolak resin, Positive photoresist compositions are described. Further, Japanese Patent Laid-Open No. 2-296249 discloses the following formula

[0006]

[Chemical 5]

[In the formula, R ^{1 to} R ⁵ are hydrogen, halogen, an alkyl group having 1 to 4 carbon atoms, an alkenyl group, an alkoxy group or a hydroxyl group (provided that at least one is a group represented by the following formula).

[0008]

[Chemical 6]

(R ⁶ and R ⁷ are halogen, an alkyl group or an alkenyl group, and n is 0, 1 or 2.)]
A positive resist composition containing a sensitizer containing a quinonediazide sulfonic acid ester of the compound represented by and an alkali-soluble phenol resin is described. Further, in Japanese Patent Laid-Open No. 62-10646, the following formula

[0010]

[Chemical 7]

[In the formula, R ^{1 to} R ³ are each hydrogen or a lower alkyl group. ] And a phenol compound represented by
A positive photoresist composition containing a sensitizer containing a condensate with quinonediazide sulfonyl chloride and an alkali-soluble phenolic resin is described. Further, JP-A-2-296248 discloses that an alkali-soluble phenol resin and a photosensitizer of the following formula

[0012]

[Chemical 8]

[Wherein R ^{1 to} R ⁵ are hydrogen, halogen, C
_{1 to} C ₄ alkyl, alkenyl or alkoxy group or hydroxyl group, provided that at least one is

[0014]

[Chemical 9]

[0015] A is -S-, -O-, -C (O)
-, -C (O) -O-, -S (O)-,-(O) S
(O) - or ^{-C (R 7) (R 8} ) - and, R ⁶ is halogen, an alkyl or alkenyl group, R ⁷ and R ⁸ are hydrogen, an alkyl group, an alkenyl group or a phenyl group, n represents 0, 1 or 2 is represented. ]

A positive resist composition containing a quinonediazide sulfonic acid ester of a compound represented by the following is described. However, with these compositions, it was not possible to resolve a pattern having a line width of 0.5 μm or less at a wide depth of focus with a good profile.

[0017]

The present invention provides a positive resist composition having an excellent balance of various performances such as resolution, profile, sensitivity, heat resistance and depth of focus.

[0018]

The present invention has the general formula

[0019]

[Chemical 10]

[In the formula, n represents an integer of 1 to 3. R
₁ , R ₂ and R ₃ each independently represent hydrogen or a halogen atom, —OCOR ₄ or an optionally substituted alkyl, cycloalkyl or alkoxy group, and R
₄ represents an optionally substituted alkyl or phenyl group, and when n is 1, R ₁ , R ₂ and R
₃ are different from each other, either of them is an optionally substituted cycloalkyl group, or R ₁ , R ₂
And R ₃ is not a hydrogen atom and one of these is another
Be different from one. Q _{1 to} Q ₁₂ each independently represent a hydrogen atom, an alkyl group or a phenyl group. Z _{1 to} Z
₅ are independent formulas below

[0021]

[Chemical 11]

(In the formula, R ₅ , R ₆ and R ₇ each independently represent hydrogen or a halogen atom, —OCOR ₄ or an optionally substituted alkyl, cycloalkyl or alkoxy group, and R ₄ is as defined above. It has the same meaning, but when n is 1, R ₅ , R ₆ and R ₇ are different from each other, or R ₅ , R ₆ and R ₇ are not hydrogen atoms and one of them is Different from the two.
p represents 0 or 1. ) Represents a group represented by. ] A positive resist composition containing a quinonediazide-based photosensitizer containing at least one quinonediazide sulfonic acid ester among the phenol compounds represented by the above and an alkali-soluble resin.

The optionally substituted alkyl group represented by R _{1 to} R ₇ and the optionally substituted alkoxy group represented by R _{1 to} R ₃ and R _{5 to} R ₇ are preferably linear or branched. And those having 1 to 6 carbon atoms. The alkyl group represented by Q _{1 to} Q ₁₂ is preferably a linear or branched one having 1 to 4 carbon atoms. Preferred R _{1 to} R ₇ include a methyl, ethyl, isopropyl or cyclohexyl group.
Preferred examples of Q _{1 to} Q ₁₂ include a hydrogen atom and a methyl group. As the phenol compounds represented by the general formulas (Ia) to (Id), those in which n is 2 or 3 are from the viewpoint of sensitivity and heat resistance, and at least one of Z _{1 to} Z ₅ is represented by the following formula.

[0024]

[Chemical 12]

[In the formula, R ₄ , R ₅ and p have the same meanings as described above. ] Are preferable from the viewpoint of sensitivity and scum. Specific examples of the phenol compounds represented by formulas (Ia) to (Id) include:

[0026]

[Chemical 13]

[0027]

[Chemical 14]

[0028]

[Chemical 15]

[0029]

[Chemical 16]

And the like.

The phenol compounds represented by the general formulas (Ia) to (Id) are represented by the following formula

[0032]

[Chemical 17]

(Wherein Q _{1 to} Q ₂ , R _{1 to} R ₃ and n have the same meanings as described above) and H
_{-Z 1 -C (Q 3) (} Q 4) -Z 2 -H, H-Z 1 -C
_{(Q 3) (Q 4)} -Z 2 -C (Q 5) (Q 6) -Z 3 -
_{H, H-Z 1 -C (} Q 3) (Q 4) -Z 2 -C (Q 5)
_{(Q 6) -Z 3 -C (} Q 7) (Q 8) -Z 4 -H or H
_{-Z 1 -C (Q 3) (} Q 4) -Z 2 -C (Q 5) (Q
_{6) -Z 3 -C (Q 7} ) (Q 8) -Z 4 -C (Q 9)
(Q ₁₀₎ -Z ₅ -H [in each formula, Z ₁ to Z ₅ and Q ₃ to Q ₁₀ are as defined above. ] Each of the compounds represented by the above can be produced by reacting in the presence of an acid catalyst such as p-toluenesulfonic acid or sulfuric acid.

The quinonediazide sulfonic acid ester of the phenol compound represented by the general formulas (Ia) to (Id) can be prepared by a known method, for example, the phenol compound represented by the general formulas (Ia) to (Id) and 1,2-naphthoquinonediazide. It can be produced by reacting a sulfonic acid halide or a 1,2-benzoquinonediazide sulfonic acid halide in the presence of a weak alkali. The amount of the quinonediazide-based photosensitizer used is usually 5 to 50% by weight, preferably 10 to 40% by weight, based on the total solid content of the positive resist composition.

The alkali-soluble resin is obtained by addition-condensing phenols and aldehydes. Examples of phenols include phenol, o-, m- or p-cresol, 2,5-xylenol, 3,5-xylenol, 3,4-xylenol, 2,3,5-trimethylphenol, 4-t-butylphenol. , 2-t-butylphenol, 3-t-butylphenol, 3-ethylphenol, 2-ethylphenol, 4-ethylphenol, 3-methyl-6-t-butylphenol, 4-methyl-2-t-butylphenol, 2- Naphthol 1,
3-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, or general formula (III)

[0036]

[Chemical 18]

(Wherein R ₄ ′ to R ₆ ′ each independently represent a hydrogen atom or an alkyl or alkoxy group having 1 to 4 carbon atoms, and k represents 1 or 2). Species or two or more species and general formula (IV)

[0038]

[Chemical 19]

(In the formula, R ₇ 'to R ₁₂ each independently represent a hydrogen atom or an alkyl or alkoxy group having 1 to 4 carbon atoms, and R ₁₃ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an aryl group. Group, a to c each represent 0, 1 or 2 and a + b + c> 2), and one or a mixture of two or more thereof. These phenols may be used alone or in combination of two or more.

Examples of aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, phenylaldehyde, α- or β-phenylpropylaldehyde,
o-, m- or p-hydroxybenzaldehyde,
Examples thereof include glutaraldehyde, glyoxal, o- or p-methylbenzaldehyde, and the like. The addition condensation of phenols and aldehydes is carried out by a conventional method in the presence of a catalyst, and the reaction conditions are usually 60 to 250 ° C. and 2 to 30 hours. Examples of the catalyst include organic acids (oxalic acid, formic acid, trichloroacetic acid, p-toluenesulfonic acid, etc.), inorganic acids (hydrochloric acid, sulfuric acid, perchloric acid, phosphoric acid, etc.) or divalent metal salts (zinc acetate, magnesium acetate, etc.) Etc. The addition condensation is carried out in bulk or in a suitable solvent. The weight average molecular weight in terms of polystyrene of the alkali-soluble resin obtained by addition condensation is 2000 to 50000.

From the viewpoint of resolution, heat resistance and scum, the alkali-soluble resin obtained by the addition condensation is subjected to, for example, an operation such as fractionation to obtain a G component having a polystyrene reduced molecular weight of 1000 or less.
The pattern area by PC (UV-254 nm, the same applies hereinafter) is preferably 25% or less, more preferably the total pattern area excluding the pattern area of unreacted phenols.
20% or less, particularly preferably 15% or less. For fractionation, alkali-soluble resin obtained by addition condensation is used as a good solvent such as alcohol (methanol or ethanol), ketone (acetone, methyl ethyl ketone or methyl isobutyl ketone), ethylene glycol and its ethers, ether esters (ethyl cellosolve acetate etc.) ) Or tetrahydrofuran, and then pouring the obtained solution into water for precipitation, or pouring into a solvent such as pentane, hexane, heptane, or cyclohexane for liquid separation. The weight average molecular weight of the alkali-soluble resin after fractionation is preferably 3000 to 20000. The preferred addition amount of the alkali-soluble resin is 60 to 90% by weight based on the total solid content in the positive resist composition. Further, an alkali-soluble compound having a molecular weight of less than 900 can be added as a sensitivity adjusting agent to the positive resist composition of the present invention. The alkali-soluble compound having a molecular weight of less than 900 is preferably a compound having at least two phenolic hydroxyl groups. More preferable alkali-soluble compounds are, for example, the compounds represented by the general formula (IV), the compounds represented by the general formula (I) in JP-A-4-50851, and the compounds disclosed in JP-A-3-179353. The compound etc. which are described by Formula (I) are mentioned. The preferred amount of the alkali-soluble compound having a molecular weight of less than 900 is 3 to 40% by weight based on the total solid content of the positive resist composition. Further, various additives such as a sensitizer, another resin, a surfactant, a stabilizer or a dye for making the formed image more visible can be added to the positive resist composition.

The solvent used for preparing the positive resist solution is preferably one which has an appropriate drying rate and which evaporates the solvent to give a uniform and smooth coating film. As such a solvent,
For example, glycol ether esters such as ethyl cellosolve acetate and propylene glycol monomethyl ether acetate, solvents described in JP-A-2-220056, esters such as ethyl pyruvate, n-amyl acetate and ethyl lactate, 2-heptanone, γ- Examples include ketones such as butyrolactone. These solvents may be used alone or in 2
Used as a mixture of two or more species. The amount of the solvent is not particularly limited as long as it can be applied on the wafer so as to form a coating film that is homogeneous and has no pinholes or uneven coating, but it is usually solid (that is, quinonediazide-based photosensitizer, alkali-soluble resin and various types of resins). A positive resist solution is prepared so that the additive) is 3 to 50% by weight.

[0043]

The positive resist composition of the present invention has an excellent balance of various properties such as resolution, profile, sensitivity, heat resistance and depth of focus required as a resist.

[0044]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, “part” means “part by weight”.

Synthesis Example 1-1 130.8 g of 37% formalin was added dropwise to a mixture of 69.12 g of bisphenol C (manufactured by Honshu Kagaku KK), 25.9 g of sodium hydroxide and 475.6 g of water at room temperature over 3 hours. After the dropping is completed,
The mixture was stirred at the same temperature for 4 hours. Then, 46.66 g of glacial acetic acid was added and stirred for 30 minutes, and then 300 g of ethyl acetate was added to completely dissolve the reaction mixture. Then, it was washed 6 times with ion-exchanged water. The obtained oil layer was concentrated, 1000 ml of methanol was added, and then concentrated to 200 g. The obtained residue was purified by column chromatography to obtain a bisphenol C dimethylol compound.

Synthesis Example 1-2 2-Cyclohexyl-5-methylphenol 226.8 g, p
After dissolving a mixture of 9.51 g of toluenesulfonic acid and 161.7 g of methanol at room temperature, a solution (82.3 g) of the dimethylol derivative of bisphenol C obtained in Synthesis Example 1-1 in methanol was added dropwise over 4 hours. After completion of dropping, the mixture was stirred at room temperature for 3 hours. Then, 1000 ml of n-heptane was added and cooled with ice water. The precipitated crystals were filtered, and the obtained cake was washed with toluene. Then, it was dried to obtain 13.2 g of a compound represented by the following formula.

[0047]

[Chemical 20]

Synthesis Example 2 A mixture of 12 g of the compound obtained in Synthesis Example 1-2, 1,76 g of 1,2-naphthoquinonediazide-5-sulfonyl chloride and 109 g of dioxane was added with 4.4 g of triethylamine at 20 to 30 ° C.
Dropped over time. After the completion of dropping, the mixture was stirred at 30 ° C for 10 hours.
Then, after adding 1.1 g of acetic acid, the mixture was stirred at the same temperature for 1 hour.
Then, the reaction mixture was filtered, and the obtained filter residue was washed with 9.8 g of dioxane. The filtrate and the washing solution were poured into a mixed solution of acetic acid (3.6 g) and ion-exchanged water (356 g), and the mixture was stirred for 1 hour. After filtering the precipitated crystals, the obtained cake was stirred and washed with 356 g of ion-exchanged water. Then, the cake obtained by filtration was dried at 40 ° C. to obtain 20 g of Photosensitizer A.

Synthesis Example 3 5.0 g of a compound represented by the following formula, naphthoquinone- (1,2)
-Diazide- (2) -5-sulfonic acid chloride 13.33 g and dioxane 92 g were dropped into a mixture of dioxane 92 g at a temperature of 20 to 30 ° C over a period of 60 minutes, and after the dropping was completed, the mixture was further stirred at the same temperature for 5 hours. . The reaction mixture is then filtered,
The obtained filtration residue was washed with 13 g of dioxane. The filtrate and the washing solution were poured into a mixed solution of acetic acid (3.2 g) and ion-exchanged water (315 g), and the mixture was stirred for 1 hour. After filtering the precipitated crystals, the obtained cake was stirred and washed with 315 g of ion-exchanged water. Then, the cake obtained by filtration was dried at 40 ° C. to obtain 16 g of Photosensitizer B.

[0050]

[Chemical 21]

Examples (Example Nos. 1-2) and Comparative Examples (Example Nos. 3-4) Alkali-soluble resin (abbreviated as resin in the table), quinonediazide type photosensitizer (abbreviated as photosensitizer in the table), and Additives having the compositions shown in the table below were mixed with 50 parts of 2-heptanone. The mixed solution was filtered through a Teflon filter having a pore size of 0.2 μm to prepare a resist solution. A silicon wafer washed by a conventional method is coated with the above resist solution using a spin coater.
It was applied to a thickness of 1.1 μm and baked on a hot plate at 90 ° C. for 1 minute. Next, a reduction projection exposure machine with an exposure wavelength of 365 nm (i-line) (Nikon product, NSR1755i7A NA = 0.5)
Was used to change the amount of exposure in steps. Then, the wafer was baked on a hot plate at 110 ° C. for 1 minute. This was developed with SOPD [developer; product of Sumitomo Chemical Co., Ltd.] for 1 minute to obtain a positive pattern. The resolution is 0.
The dimension of the line-and-space pattern that separates without film loss was evaluated by a scanning electron microscope at an exposure amount (effective sensitivity) at which the 50-μm line-and-space pattern became 1: 1. As for the profile, the cross-sectional shape of the 0.45 μm line-and-space pattern at the effective sensitivity was observed with a scanning electron microscope. The depth of focus was measured by observing a cross section of the focus width at which the 0.45 μm line-and-space pattern is separated without film loss at the effective sensitivity with a scanning electron microscope. As for scum, 0.45μ at the best focus in effective sensitivity
The presence or absence of a space between the lines of the m line and space was examined.
The heat resistance was indicated by the temperature of the hot plate when the obtained positive pattern was left on the direct hot plate for 3 minutes and the deformation of the 3 μm line and space pattern started.

[0052]

[Table 1]

The photosensitizers H to I in the above table were prepared by reacting the following phenol compounds H'to I'with naphthoquinone- (1,2) -diazide- (2) -5-sulfonic acid chloride in the same manner as in Synthesis Example 2. The reaction molar ratios are
2.0].

[0054]

[Chemical formula 22]

Resin a: a novolak resin obtained by reacting under reflux with an oxalic acid catalyst at a molar ratio of m-cresol / p-cresol = 70/30, cresol / formalin = 1 / 0.8 Molecular weight 60 for the total pattern area excluding the pattern area of reactive phenols
Alkali-soluble resin having an area ratio of 00 or less of 34%, an area ratio of molecular weight of 1000 or less of 15%, and a weight average molecular weight of 8000 (both molecular weights are in terms of polystyrene).

Additive: A compound represented by the following formula.

[0057]

[Chemical formula 23]

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Hiroshi Sakamoto 3-98 Kasugade, Konohana-ku, Osaka City, Osaka Prefecture Sumitomo Chemical Co., Ltd. (72) Inventor Hirotoshi Nakanishi Kasuga, Konohana-ku, Osaka City, Osaka Prefecture 3-3-198 Naka Sumitomo Chemical Co., Ltd. (72) Inventor Haruki Ozaki 3-1-198 Kasuga, Konohana-ku, Osaka City, Osaka Prefecture Sumitomo Chemical Co., Ltd.

Claims (3)

[Claims] 1. A general formula: [In formula, n represents the integer of 1-3. R ₁ , R ₂ and R
₃ are each independently hydrogen or halogen atom, -OCO
R ₄ represents an optionally substituted alkyl, cycloalkyl or alkoxy group, R ₄ represents an optionally substituted alkyl or phenyl group, and n
Is 1, R ₁ , R ₂ and R ₃ are different from each other, either of them is a cycloalkyl group which may be substituted, or R ₁ , R ₂ and R ₃ are hydrogen. It is not an atom and one of these is different from the other two. Q _{1 to} Q ₁₂ each independently represent a hydrogen atom, an alkyl group or a phenyl group. Z _{1 to} Z ₅ are independently the following formulas: (In the formula, R ₅ , R ₆ and R ₇ each independently represent hydrogen or a halogen atom, —OCOR ₄ or an optionally substituted alkyl, cycloalkyl or alkoxy group, and R ₄ has the same meaning as described above. When n is 1, R ₅ , R ₆ and R ₇ are different from each other, or R ₅ , R ₆ and R ₇ are not hydrogen atoms and one of them is different from the other two. And p represents 0 or 1). ] A positive resist composition containing a quinonediazide-based photosensitizer containing at least one quinonediazide sulfonic acid ester among the phenol compounds represented by the above and an alkali-soluble resin. 2. In the general formulas (Ia) to (Id), n is 2
The positive resist composition according to claim 1, wherein the positive resist composition is 3 or 3. 3. In formulas (Ia) to (Id), Z ₁ to
At least one of Z ₅ is represented by the following formula: [In the formula, R ₄ , R ₅ and p have the same meanings as described above. ] The positive type resist composition of Claim 1 or 2 represented by these.