JPH0553315A - Positive type resist composition - Google Patents

Abstract

PURPOSE:To maintain various performances, such as profile, heat resistance and residual film ratio, and to improve a sensitivity, resolution and value by incorporating an alkali-soluble resin, quinonediazide compd. and a specific phenol compd. into the above compsn. CONSTITUTION:This compsn. contains the alkali-soluble resin, the quinonediazide compd. and the phenol compd. expressed by formula I. These compds. are obtd. by bringing 1,5-dihydroxynaphthalene and 3-hydrox-alpha-methyl styrene or 4- hydroxy-alpha-methyl styrene into reaction in the presence of an acid catalyst. The quinonediazide compd. is not particularly limited and includes, for example, 1,2-naphthoquinonediazide-4-sulfulate, 1,2-naphthoquinonediazide-5-sulfonate. The alkali-soluble resin used for the compsn. is not particularly limited and includes, for example, a polybiphenol or novolak resin, etc.

Description

Detailed Description of the Invention

[0001]

The present invention relates to ultraviolet rays, far ultraviolet rays (including excimer lasers, etc.), electron beams, ion beams,
The present invention relates to a positive resist composition sensitive to radiation such as X-rays.

[0002]

2. Description of the Related Art A composition containing a compound having a quinonediazide group and an alkali-soluble resin is 300 nm to 500 nm.
It is used as a positive resist by taking advantage of the fact that the quinonediazide group is decomposed to generate a carboxyl group by irradiation with light having a wavelength of nm to change from an alkali-insoluble state to an alkali-soluble state. The positive resist has a feature that it has a remarkably excellent resolution as compared with the negative resist, and is used for manufacturing integrated circuits such as IC and LSI.

In recent years, the miniaturization of integrated circuits has advanced along with the high integration, and nowadays, submicron pattern formation is required, and a positive type resist excellent in profile, resolution and γ value is demanded. Conventionally, a mask contact method has been used for forming an integrated circuit, but it is said that the limit is 2 μm in this method, and a reduction projection exposure method is drawing attention instead of this. This method is a method in which a master mask (reticle) pattern is reduced and projected by a lens system to be exposed, and the resolution can be up to submicron. However, one of the problems in the reduction projection exposure method is that the throughput is low. That is, unlike the batch exposure method such as the conventional mask contact method, the reduction projection exposure method is divided repetitive exposure, and therefore the total exposure time per wafer becomes long.

As a method for solving this, it is most important to improve the sensitivity of the resist used as well as to improve the apparatus. If the exposure time can be shortened by increasing the sensitivity, the throughput can be improved and the yield can be improved. On the other hand, as the degree of integration of LSI is improved and the width of wiring is made finer, etching is being performed by plasma or the like in addition to conventional wet etching. Due to this dry etching, the dry etching resistance (heat resistance) of the resist is required more than ever.

For example, in order to achieve high sensitivity,
There is a method of reducing the molecular weight of the alkali-soluble resin used for the positive type resist. When the molecular weight of the alkali-soluble resin is low, the dissolution rate in the alkali developing solution is increased, and the sensitivity of the resist is apparently increased. However, in this method, the film loss in the non-exposed area becomes large (so-called residual film rate decreases), the profile deteriorates, and the difference in dissolution rate between the exposed area and the non-exposed area in the developing solution becomes small. In addition to the problems of so-called reduction of γ value and resolution, a very serious inconvenience occurs that the heat resistance of the resist is reduced, or the adhesion with the substrate is reduced. As another method for improving the sensitivity of the resist, there is a method of increasing the developing time or increasing the alkali concentration of the developing solution. However, even in these methods, the solubility of the resist in the developing solution is increased, so that the apparent sensitivity is certainly improved, but the residual film rate is lowered, and the resolution is lowered, which is not preferable.

[0006]

That is, at present, there is no positive type resist having all of sensitivity, resolution, residual film rate, profile and heat resistance, and if one is improved, the other becomes worse. There is an extremely inconvenient situation.

The object of the present invention is to solve the above-mentioned problems of the prior art for the production of integrated circuits,
Sensitivity, resolution and γ
It is to provide a positive resist composition having an excellent value.

[0008]

The positive resist composition of the present invention is a positive resist composition containing an alkali-soluble resin, a quinonediazide compound and a phenol compound represented by the following formula (I).

[0009]

[Chemical 2]

As the compound represented by the above formula (I),
Some examples are as follows.

[0011]

[Chemical 3]

These compounds can be obtained by reacting 1,5-dihydroxynaphthalene with 3-hydroxy-α-methylstyrene or 4-hydroxy-α-methylstyrene in the presence of an acid catalyst.

The quinonediazide compound of the present invention is not particularly limited. For example, 1,2-benzoquinonediazide-
Examples thereof include 4-sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid ester, and 1,2-naphthoquinonediazide-5-sulfonic acid ester. These esters are obtained by a known method, for example, by subjecting a quinonediazidesulfonic acid halide such as naphthoquinonediazidesulfonic acid chloride or benzoquinonediazidosulfonic acid chloride to a condensation reaction with a compound having a hydroxyl group in the presence of a weak alkali. ..

As the compound having a hydroxyl group,
Hydroquinone, resorcin, phloroglucin, 2,4
-Dihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 2,2 ', 3-trihydroxybenzophenone, 2,2', 4-trihydroxybenzophenone, 2,2 ', 5-trihydroxybenzophenone, 2,3 , 3'-trihydroxybenzophenone,
2,3,4'-trihydroxybenzophenone, 2,
3 ', 4-trihydroxybenzophenone, 2,3',
5-trihydroxybenzophenone, 2,4,4'-trihydroxybenzophenone, 2,4 ', 5-trihydroxybenzophenone, 2', 3,4-trihydroxybenzophenone, 3,3 ', 4-trihydroxybenzophenone, Trihydroxybenzophenones such as 3,4,4′-trihydroxybenzophenone, 2,3
3 ', 4-tetrahydroxybenzophenone, 2,3
4,4'-tetrahydroxybenzophenone, 2,
2 ', 4,4'-tetrahydroxybenzophenone,
2,2 ', 3,4-tetrahydroxybenzophenone,
2,2 ', 3,4'-tetrahydroxybenzophenone, 2,2', 5,5'-tetrahydroxybenzophenone, 2,3 ', 4', 5-tetrahydroxybenzophenone, 2,3 ', 5,5 '-Tetrahydroxybenzophenones such as tetrahydroxybenzophenone,
2,2 ', 3,4,4'-pentahydroxybenzophenone, 2,2', 3,4,5'-pentahydroxybenzophenone, 2,2 ', 3,3', 4-pentahydroxybenzophenone, 2, Pentahydroxybenzophenones such as 3,3 ′, 4,5′-pentahydroxybenzophenone, 2,3,3 ′, 4,4 ′, 5′-hexahydroxybenzophenone, 2,2 ′, 3,3 ′, 4 ，
Examples thereof include hexahydroxybenzophenones such as 5'-hexahydroxybenzophenone, gallic acid alkyl esters, oxyflavans, and phenol compounds represented by the general formula (I) described in JP-A-2-269351.

In particular,

[0016]

[Chemical 4]

[Wherein q represents a number of 0 or more and 4 or less, r represents a number of 1 or more and 5 or less, and q + r is 2 or more. R _{1 to} R ₅ each independently represent a hydrogen atom, an alkyl group, an alkenyl group, a cyclohexyl group or an aryl group. However, either R ₄ or R ₅ represents an alkyl group, an alkenyl group, a cyclohexyl group or an aryl group. ) And the like oxyflavans are preferable from the viewpoint of solubility in a solvent.

The alkali-soluble resin used in the composition of the present invention is not particularly limited, and examples thereof include polyvinyl phenol and novolac resins. The novolac resin is, for example, phenol, o-cresol, m-cresol, 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 and the like, alone or in combination of two or more. , A resin condensed with a carbonyl compound by a conventional method.

The carbonyl compounds include formaldehyde, paraformaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, phenylacetaldehyde, α-phenylpropylaldehyde, β-phenylpropylaldehyde, toluylbenzaldehyde,
Mesitylbenzaldehyde, phenethylbenzaldehyde, o-hydroxybenzaldehyde, m-hydroxybenzaldehyde, p-hydroxybenzaldehyde,
o-chlorobenzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde, o-nitrobenzaldehyde, m-nitrobenzaldehyde, p-nitrobenzaldehyde, o-methylbenzaldehyde, m-
Methylbenzaldehyde, p-methylbenzaldehyde, p-ethylbenzaldehyde, pn-butylbenzaldehyde, acrolein, crotonaldehyde, cinnamaldehyde, acetone, methylethylketone, diethylketone, methylisobutylketone, methylphenylketone, methylbenzylketone, glutaraldehyde, Examples thereof include glyoxal.

The weight ratio of these quinonediazide compound and alkali-soluble resin is preferably in the range of 1: 1 to 1: 8.

The solvent which can be used in the present invention is preferably one which has an appropriate drying rate and gives a uniform and smooth coating film. Examples of such a solvent include glycol ether esters such as ethyl cellosolve acetate and propylene glycol monomethyl ether acetate, the solvent described in JP-A-2-220056, and evaporation determined by a weight method using n-butyl acetate as 100. Examples thereof include a mixed solvent containing an organic solvent having a rate of 1 to 24 and an organic solvent having an evaporation rate of 25 to 150. Evaporation rate is 1-2
As the organic solvent which is 4, γ-butyrolactone, cyclohexanol, diacetone alcohol, butyl cellosolve, ethyl lactate, butyl lactate and the like have an evaporation rate of 25 to
Examples of the organic solvent which is 150 include cyclohexanone, methyl lactate, methyl diacetone alcohol, 2-heptanone, n-amyl acetate, diisopropyl ketone, and n-acetate.
Butyl and the like can be mentioned. The amount of solvent is not particularly limited as long as it is possible to apply a coating film that is homogeneous on the wafer and has no pinholes and uneven coating, but when ethyl cellosolve acetate is used, it is relative to the total weight of the resist composition. It is preferably used in the range of 30 to 80% by weight. In the composition of the present invention, if necessary, for example, a sensitizer, other added resin, a surfactant, a stabilizer, or a dye for making a formed image more visible, and the like, ordinarily in the technical field. Various conventionally used additives can be added.

[0022]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto.

Synthesis Example A 300 ml four-necked flask was equipped with a stir bar and a thermometer, and 32 g of 1,5-dihydroxynaphthalene, 8.9 g of 3-hydroxy-α-methylstyrene, 32 g of acetic acid, 120 g of tetrahydrofuran and 96% sulfuric acid. 5 g was charged, completely dissolved, and reacted at 55-60 ° C. for 50 hours. Tetrahydrofuran in the reaction mass was distilled off, and the precipitate was filtered off and washed with water. Further, this was dissolved in toluene, washed with water, and the oil layer was concentrated. Toluene, chloroform and n-hexane were added to the obtained product for recrystallization. After drying, 6 g of the target compound represented by the following formula was obtained.

[0024]

[Chemical 5]

Examples and Comparative Examples A novolak resin, a quinonediazide sulfonic acid compound, and the phenol compound obtained in the Synthesis Example were dissolved in 48 parts of ethyl cellosolve acetate in the composition shown in Table 1. A resist solution was prepared by filtering the prepared solution with a 0.2 μm Teflon filter. This was applied to a silicon wafer washed by a conventional method to a thickness of 1.3 μm using a spin coater. Then, the silicon wafer was baked on a hot plate at 100 ° C. for 60 seconds. Next, a reduction projection exposure machine (NSR 1505G3C NA manufactured by Nikon Corporation) having an exposure wavelength of 436 nm (g line) was applied to this wafer.
= 0.42) and the exposure amount was changed stepwise for exposure. A positive pattern was obtained by developing this with a developer SOPD manufactured by Sumitomo Chemical for 1 minute.

The resolution was the exposure amount at which the 0.8 μm line-and-space pattern became 1: 1 and the dimension of the line-and-space pattern which was separated without film reduction was evaluated by SEM (scanning electron microscope). For the γ value and the sensitivity, the normalized film thickness (= remaining film thickness / initial film thickness) is plotted with respect to the logarithm of the exposure amount, the inclination θ is obtained, and tan θ is taken as the γ value, and the normalized film thickness becomes 0. The exposure amount was taken as the sensitivity. The results are shown in Table 1.

[0027]

[Table 1]

1) Novolak Resin A A novolak resin having a weight average molecular weight of 4000 (in terms of polystyrene) obtained by reacting with formalin at a charged molar ratio of metacresol / paracresol = 40/60. Novolac resin B Novolak resin with a weight average molecular weight of 15500 obtained by separating a novolak resin with a weight average molecular weight of 9600 (in terms of polystyrene) obtained by reacting with formalin at a charged molar ratio of metacresol / paracresol = 55/45. .. (Polystyrene conversion molecular weight 900 by GPC
The following surface percentage is 7%. ) 2) Quinonediazide compound A condensation reaction product of 2,3,4,4'-tetrahydroxybenzophenone and 1,2-naphthoquinonediazide- (2) -5-sulfonic acid chloride. (Reaction molar ratio 1: 2.7)

[0029]

The positive resist composition of the present invention is a resist composition excellent in sensitivity, resolution and γ value.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasunori Uetani 3-98 Kasugade, Konohana-ku, Osaka-shi, Osaka Sumitomo Chemical Co., Ltd. (72) Inventor Ayako Ida Kasuga, Konohana-ku, Osaka-shi, Osaka Naka 3-chome 1-98 Sumitomo Chemical Co., Ltd.

Claims (1)

[Claims] 1. A positive resist composition containing an alkali-soluble resin, a quinonediazide compound and a phenol compound represented by the following formula (I). [Chemical 1]