JPH07138249A - Bis-t-butoxycarbonyl methyl thymolphthalein, its sinthesis and resist material containing the same - Google Patents

Abstract

PURPOSE:To provide the subject new compound useful as a dissolution inhibitor for e.g. positive-type resist materials sensitive to high-energy beams. CONSTITUTION:The objective bis-t-butoxycarbonylmethyl thymolphthalein of formula I, which can be obtained by reaction between thymolphthalein of formula II and a t-butoxycarbonylalpha-haloacetic acid. The other objective positive-type resist material capable of developing with an aqueous alkaline solution comprises (A) a poly(hydroxystyrene) resin, (B) the compound of the formula I as dissolution inhibitor and (C) an onium salt at the respective weight fractions: 0.55<=A, 0.07<=B<=0.40 and 0.005<=C<=0.15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive resist material, and in particular, it has a high sensitivity to high-energy rays such as deep ultraviolet rays, electron beams and X-rays, and can be developed with an alkaline aqueous solution. The present invention relates to a positive resist material suitable for processing.

[0002]

2. Description of the Related Art Conventionally, with the high integration and high speed of LSIs (high-density integrated circuits), miniaturization of pattern rules has been demanded, but light emitted from a light source used in a normal optical exposure technique is required. Has a long wavelength and is not a single wavelength, so there is a limit to the miniaturization of the pattern rule. Therefore, g-rays (wavelength 436 nm) or i-rays (wavelength 365 nm) emitted from an ultra-high pressure mercury lamp are also used as a light source.

However, even in this case, about 0.5 μ
The pattern rule of the resolution of m is the limit, and the LSI that can be manufactured is only the degree of integration of about 16 Mbit DRAM. Therefore, in recent years, far-ultraviolet lithography, which uses far-ultraviolet rays as a light source and has a shorter wavelength than g-line and i-line, is regarded as promising.

According to deep ultraviolet lithography, it is 0.1
It is also possible to form a pattern rule of up to 0.3 μm, and when a resist material having low light absorption is used,
It is possible to form a pattern having a side wall that is nearly vertical to the substrate, and it is also possible to transfer the pattern at once, so that the pattern formation processing efficiency (throughput) is higher than that of lithography using an electron beam. Excellent in high points. Moreover, in recent years, high-intensity K
Since the use of the rF excimer laser has become possible, it is necessary to use a highly sensitive resist material from the viewpoint of mass-producing LSI using the light source.

Therefore, in recent years, a chemically amplified resist material has been developed which has sensitivity equal to or higher than that of the conventional high-sensitivity resist material, and has high resolution and high dry etching resistance and which is produced by using an acid as a catalyst (for example, Ryu). (Liu)
Et al., Journal of Vacuum Science and Technology (J. Vac. Techno.), Volume B6, page 379, 1988, Already Shipley (S.
hipley) has commercialized a chemically amplified negative resist material (SAL601ER7: trade name of Shipley), which is composed of three components of a novolac resin, a melamine compound and an acid generator.

However, when a negative resist material is used in the LSI manufacturing process, it is easy to form wirings and gate portions, but it is difficult to form contact holes that require fine processing. There was a drawback that was. In addition, when patterning is performed with deep ultraviolet rays, electron beams or X-rays using the conventionally proposed chemically amplified positive type resist material as it is,
Since the solubility of the resist surface decreases and the pattern after development tends to overhang, it becomes difficult to control the size of the pattern, and the dimensional controllability during substrate processing using dry etching is improved. It had a drawback that it not only damages but also easily causes the pattern to collapse [K. G. Chion et al., Journal of Vacuum Science and Technology, B7].
Vol., (6), p. 1771, 1989].

Therefore, there has been a strong demand for the development of a high-performance, chemically-amplified positive resist material which does not have such drawbacks. In response to such a demand, Ito et al. Have proposed a chemically amplified type in which an onium salt is added to a poly (butoxycarbonyloxystyrene) (called PBOCST) resin in which the OH group of polyhydroxystyrene is protected by t-butoxycarbonyl group. Proposal of positive resist materials (Polymers in Electronics, AC
S symposium series [Polymers in
Electronics, ACS symposo
um Series 242 (American Chemical Society, Washington DC. 1984), p. 11]).

However, since the above-mentioned onium salt contains antimony as a metal component, it has a drawback of contaminating the substrate. In addition, Ueno et al.
Styreneoxytetrahydropyranyl) as the main component,
A positive type resist material for deep ultraviolet rays obtained by adding an acid generator to this has been proposed (36th Joint Lecture Meeting of Japan Society of Applied Physics, 1989, 1p-k-7). However,
The positive resist material has a drawback that it is easy to invert from a positive type to a negative type with respect to deep ultraviolet rays, electron beams or X-rays.

In addition to the above-mentioned drawbacks, the two-component positive resist composition comprising a resin in which an OH group is protected by a protecting group and an acid generator as described above is required to be dissolved in a developing solution. Since it is necessary to decompose many protecting groups, LSI
In the manufacturing process, there is a drawback that the film thickness of the resist is changed and stress or bubbles are easily generated in the film. Therefore, a three-component positive resist material comprising an alkali-soluble resin, a dissolution inhibitor and an acid generator has been developed as a chemically amplified positive resist material that has improved the drawbacks of the above two-component positive resist material. ing.

As such a three-component positive resist material, a resist material (RA containing a novolak resin, an acetal compound as a dissolution inhibitor and an acid generator) is added.
Y / PF resist material: Hoechst) has been developed for X-ray lithography. However, since this resist material undergoes chemical amplification at room temperature, the resist sensitivity remarkably depends on the time from X-ray exposure to development. Therefore, it is necessary to control the time strictly at all times, but it is difficult to control the time, so that the dimension of the pattern cannot be stabilized, and the absorption of the KrF excimer laser light (wavelength 248 nm) is not possible. Due to its large size, it has a drawback that it is unsuitable for use in lithography using the laser.

By the way, in order to carry out chemical amplification, heat treatment is generally required after exposure in many cases. In this case, although the number of steps is increased as compared with the case of a resist material which is chemically amplified at room temperature, it is not necessary to strictly control the time from exposure to development, so that the resist characteristics are stable. . Further, in the case of a system in which hydrolysis is performed in the process of performing chemical amplification, water is required for hydrolysis, so it is necessary to incorporate water into the resist material.

However, as the solvent used for coating the resist material on the substrate, an organic solvent which is not soluble in water, such as ethoxyethyl acetate, is generally used.
Further, since many resins themselves used as resist materials are not compatible with water, it is difficult to contain water in the resist material, and even if the resin is contained, the control of the water becomes complicated.

On the other hand, in the decomposition reaction of the t-butoxycarbonyloxy group, the reaction proceeds with the two components of the t-butoxycarbonyloxy group and the acid which is the catalyst, and water is not required. Therefore, chemical amplification is performed. It is suitable for this purpose.
Further, since many compounds having a t-butoxycarbonyloxy group have an effect of inhibiting the solubility of the novolak resin, it is known that the t-butoxycarbonyloxy group has a dissolution inhibiting effect on the novolak resin. Has been.

From such a viewpoint, Schlegel (Sch
legel) is a novolac resin, bisphenol A
We have proposed a three-component posi type resist material consisting of a dissolution inhibitor with a t-butoxycarbonyl group introduced into it and pyrogallol methanesulfonate (Spring Lee 1990, The 37th Annual Meeting of the Japan Society for Applied Physics). , 28p-
ZE-4). However, in this case, it is difficult to put it into practical use because the light absorption of the novolac resin is large.

Further, Schwarm et al. Have developed bis (pt-butoxycarbonyloxyphenyl) iodonium hexafluoroantimonate as a material which serves as both a dissolution inhibitor and an acid generator [Polymer Fore Microelectronics
r for Microelectronics), Tokyo, 1989, Session A38], and proposes a positive resist material for deep ultraviolet rays in which this is mixed with a novolac resin. However, the above-mentioned positive resist material has a drawback that it is difficult to put into practical use because the novolac resin has a large light absorption and contains a metal.

By the way, in a three-component chemically amplified positive resist composition comprising a resin, a dissolution inhibitor and an acid generator, the dissolution rate of the resist film in an alkaline developer should be controlled by the dissolution inhibitor [(high Dissolution rate of the part irradiated with energy rays) / (Dissolution rate of the non-irradiated part)
It is known that (increasing the dissolution rate ratio)] has a great influence on the performance as a resist material. That is, when a substance (dissolution inhibitor) that rapidly dissolves the portion of the resist film when exposed to high energy rays such as ultraviolet rays to the alkali developing solution is added to the resist material, The formation efficiency becomes extremely good.

Examples of conventionally known such dissolution inhibitors include di (t-butoxycarbonyl) bisphenol A represented by the following chemical formula 3 and di (t-butoxycarbonyl) represented by the following chemical formula 4. ) Bisphenol F,
4-t-butoxycarbonylbiphenyl represented by the following chemical formula 5, t-butyl cholate represented by the following chemical formula 6, and t-butyl deoxycholate represented by the following chemical formula 7 are mentioned.

[0018]

[Chemical 3]

[Chemical 4]

[Chemical 5]

[Chemical 6]

[Chemical 7] (However, in Chemical formula 3, Chemical formula 4, and Chemical formula 5, t-Bu-t represents a t-butyl group.) However, since any of these dissolution inhibitors have the following defects, the resist material It was difficult to put it into practice.

The above-mentioned drawbacks are that, in the case of di (t-butoxycarbonyl) bisphenol A and di (t-butoxycarbonyl) bisphenol F, they have a great effect of inhibiting dissolution of the resin and have a small ultraviolet absorption rate. Although it has a characteristic that it is inexpensive, the addition rate is limited because the dissolution rate ratio is small and the compatibility with the resin is low, and in the case of 4-t-butoxycarbonylbiphenyl, Although the dissolution rate ratio is relatively large, it is impossible to control the light transmittance to the resist film due to the large ultraviolet absorption rate.

Further, in the case of t-butyl deoxycholate, the ultraviolet absorption is small, and when it is used for a novolac resin, it has good compatibility and is excellent as a dissolution inhibitor. When it is used for (hydroxystyrene), the dissolution inhibiting effect is insufficient, so that the film loss phenomenon occurs in which the resist film in the non-irradiated part dissolves in the alkali developing solution. It means that the supply is unstable because is a natural product. Furthermore, when polyhydroxystyrene is used as the film-forming resin and the dissolution inhibitors mentioned so far are combined, the solubility of these dissolution inhibitors in polyhydroxystyrene is insufficient and alkali dissolution Due to insufficient suppression effect, it was difficult to control the initial film loss of the resist.

[0021]

Therefore, in a chemically amplified positive resist composition in which a resin is combined with a dissolution inhibitor and an acid generator, as a result of intensive studies to solve the drawbacks of the conventional dissolution inhibitors, the present invention was found. Have found that bis-t which is a novel compound for poly (hydroxystyrene) resin.
-By combining butoxycarbonylmethylthymolphthalein as a dissolution inhibitor, it has been found that a positive resist material for high energy rays having unprecedented high sensitivity, high resolution and excellent process suitability can be obtained. The invention was reached.

Therefore, a first object of the present invention is to provide a novel compound, bis-t-butoxycarbonylmethylthymolphthalein. A second object of the present invention is to provide a method for producing bis-t-butoxycarbonylmethylthymolphthalein. A third object of the present invention is to provide a positive resist material for high energy rays having unprecedentedly high sensitivity, high resolution and excellent process suitability.

[0023]

Means for Solving the Problems The above-mentioned objects of the present invention have been achieved by novel compounds such as bis-t-butoxycarbonylthymolphthalein, a method for producing the same, poly (hydroxystyrene) resin a, and a dissolution inhibitor. b and onium salt c in weight fractions of 0.55 ≦ a and 0.07 ≦
b ≦ 0.40, 0.005 ≦ c ≦ 0.15 and a + b
A positive resist material which is contained so that + c = 1 and which can be developed with an alkaline aqueous solution and is sensitive to high energy rays, wherein the dissolution inhibitor b is represented by the following chemical formula 8. Achieved by a positive resist material characterized by being t-butoxycarbonylmethylthymolphthalein.

[0024]

[Chemical 8] It should be noted that bis-t-butoxycarbonylmethylthymolphthalein represented by the above chemical formula 8 is t-butoxycarbonyl α
-A novel compound formed by reacting haloacetic acid with thymolphthalein represented by the following chemical formula 9.

[Chemical 9]

This compound can be synthesized using thymolphthalein, which is easily available as a commercial product, as a raw material. That is, it can be produced by reacting thymolphthalein with α-halogenated acetic acid tertiary butyl ester in a solvent in the presence of an appropriate acid trapping agent. As the α-halogenated acetic acid, α-chloroacetic acid tertiary butyl ester or α-bromoacetic acid tertiary butyl ester is used, and the acid trap agent is not particularly limited as long as it is a weak base, but sodium carbonate, Carbonates such as potassium carbonate, sodium hydrocarbon and potassium hydrocarbon, and tertiary amines such as triethylamine and dimethylaniline are preferably used.

The reaction solvent is not particularly limited, but it is preferable to use an aprotic polar solvent such as dimethylformamide, dimethylacetamide or dimethylsulfoxide. The reaction temperature may range from room temperature to the boiling point of the reaction solvent,
The reaction time is not particularly limited, but the reaction is completed within a range of approximately 1 hour to 10 hours. The compound of the present invention thus synthesized contains some impurities, which can be easily removed by washing the residue with a solvent or performing chromatography. The present compound thus produced is isolated as a pure substance by performing a recrystallization operation.

The content of the dissolution inhibitor b in the resist material is used in a ratio sufficient to control the alkali solubility of the resist film, but it is generally preferably in the range of 7 to 40% by weight. If the content is less than 7% by weight, the dissolution inhibiting effect is small, and if it is 40% by weight or more, the mechanical strength and heat resistance of the resist film are lowered. By the way, when bis-t-butoxycarbonylmethylthymolphthalein of the present invention is added as a dissolution inhibitor, even when polyhydroxystyrene is used as a base resin for film formation, it is not It is possible to sufficiently control the film loss, and since the portion that has been irradiated with light becomes alkali-soluble, it exhibits extremely excellent performance as a resist.

That is, this dissolution inhibitor has a sufficient dissolution inhibitory effect on polyhydroxystyrene, while the protective group is easily removed under acidic conditions formed by irradiation of the acid generator with light, resulting in a phenolic hydroxyl group. And a compound having a carboxylic acid group. In this case, a large alkali dissolution rate can be obtained because carboxylate ions are generated in particular.

When polyhydroxystyrene having a wide molecular weight distribution, such as obtained by radical polymerization, is used, the resist material contains a large molecular weight that is difficult to dissolve in an alkaline aqueous solution. It will cause hem pulling after formation. Therefore, it is preferable to use monodisperse polyhydroxystyrene as obtained by living polymerization.

Incidentally, in the present invention, a resist material using polyhydroxystyrene obtained by living polymerization (for example, one having an average molecular weight of 10,000 and a molecular weight distribution of 1.1) is used, and a resist material having a thickness of 0.2 μm is used. When the pattern of the line and the space is formed, it is possible to form the pattern with good precision without the hem. Moreover, even if the pattern thus obtained is baked at 150 ° C. for 10 minutes, no deformation is observed in the pattern and the heat resistance is sufficient.

On the other hand, a resist material using polyhydroxystyrene obtained by radical polymerization (for example, one having an average molecular weight of 12,000 and a molecular weight distribution of 3.0) was used to obtain a line of 0.5 μm. When the space pattern is formed, the heat resistance of the pattern is almost the same, but since the hem is visible, a resolution of 0.2 μm cannot be obtained.

The monodispersity means that the molecular weight distribution is Mw / Mn.
= 1.05 to 1.50. However, M
w is the weight average molecular weight of the polymer, and Mn is the number average molecular weight. In the case of living polymerization, the weight average molecular weight can be easily calculated by calculating from the weight of the monomer and the number of moles of the initiator, or by using the light scattering method. Moreover, the number average molecular weight is easily measured using a membrane osmometer.

The molecular weight distribution can be evaluated by gel permeation chromatography (GPC), the molecular structure of which is infrared absorption (IR) spectrum or ¹ H.
-It can be easily confirmed by the NMR spectrum. As a method for obtaining a monodisperse polymer, firstly, a polymer having a wide molecular weight distribution obtained by polymerization by a radical polymerization method or the like is fractionated, and secondly, a monodisperse polymer is initially prepared by a living polymerization method. A method of obtaining the same is mentioned, but it is preferable to adopt the living polymerization method because the step of monodispersion is simple.

By the way, even if the p-hydroxystyrene monomer is subjected to living polymerization as it is, polymerization does not start because the hydroxyl group of the monomer reacts with the polymerization initiator. Therefore, a method is used in which a monomer introduced with a protective group for protecting the hydroxyl group is subjected to living polymerization and then the protective group is eliminated to obtain the target parahydroxystyrene. Examples of the protective group used include a tertiary butyl group, a dimethylphenylcarbylmethylsilyl group, a tertiary butoxycarbonyl group, a tetrahydropyranyl group, and a tertiary butyldimethylsilyl group.

For example, it can be easily obtained by subjecting a monomer represented by the following Chemical formula 10 or Chemical formula 11 to living anionic polymerization and then eliminating a dimethylphenylcarbylsilyl group or a t-butyl group.

[Chemical 10]

[Chemical 11]

In the above living anionic polymerization, it is preferable to use an organometallic compound as a polymerization initiator. Preferred organometallic compounds include, for example, n-butyllithium, sec-butyllithium, tert-butyllithium, sodium naphthalene, anthracene sodium, α-methylstyrenetetramage sodium,
Examples thereof include organic alkali metal compounds such as cumyl potassium and cumyl cesium.

Living anionic polymerization is preferably carried out in an organic solvent. The organic solvent used in this case is a solvent such as an aromatic hydrocarbon, a cyclic ether, or an aliphatic hydrocarbon, and specific examples thereof include benzene and
Examples thereof include toluene, tetrahydrofuran, dioxane, tetrahydropyran, dimethoxyethane, n-hexane and cyclohexane.

These organic solvents may be used alone or as a mixture, but tetrahydrofuran is particularly preferably used. Monomer concentration during polymerization is 1
Appropriately ˜50% by weight, especially 1-30% by weight, and the reaction is preferably carried out under high vacuum or under an atmosphere of an inert gas such as argon or nitrogen with stirring.

The reaction temperature can be arbitrarily selected within the range of -100 ° C to the boiling temperature of the organic solvent used. Especially when a tetrahydrofuran solvent is used
It is preferable to carry out the reaction at 78 ° C to 0 ° C and at room temperature when a benzene solvent is used. By carrying out the reaction for about 10 minutes to 7 hours under the above conditions, only the vinyl group selectively reacts and polymerizes, and for example, a polymer represented by the following Chemical formula 12 or Chemical formula 13 can be obtained.

[0040]

[Chemical 12]

[Chemical 13] When the desired degree of polymerization is reached, for example methanol, water,
A living polymer having a desired molecular weight can be obtained by adding a polymerization reaction terminator such as methyl bromide to the reaction system to stop the polymerization reaction.

Further, the living polymer can be purified and isolated by precipitating the obtained reaction mixture with a suitable solvent (for example, methanol), washing and drying. In the polymerization reaction, the yield of living polymer produced is about 100 because the monomers react 100%.
%. Therefore, the molecular weight of the living polymer obtained can be appropriately adjusted by adjusting the amount of the monomer used and the number of moles of the reaction initiator.

The molecular weight distribution of the living polymer thus obtained is monodisperse (Mw / Mn = 1.05 to 1.
50). Furthermore, by cleaving the ether bond of the dimethylphenylcarbinylvinyldimethylsilyl group or t-butyl group of the polymer represented by Chemical formula 12 or Chemical formula 13, poly (p-hydroxystyrene) represented by the following Chemical formula 14 is obtained. Can be obtained.

[Chemical 14]

The above reaction for cleaving the ether bond is carried out by dissolving the polymer represented by Chemical formula 12 or Chemical formula 13 in a solvent such as dioxane, acetone, acetonitrile, benzene or a mixed solvent thereof, and then adding hydrochloric acid or hydrobromic acid. Alternatively, it can be easily carried out by adding an acid such as paratoluenesulfonic acid pyridinium salt dropwise. In the above reaction, the main chain of the polymer is not cleaved and the crosslinking reaction between the molecules does not occur, so that the obtained poly (p-hydroxystyrene) is monodisperse.

The onium salt c used in the present invention is
It is not particularly limited as long as it is for a conventional chemically amplified photoresist, but it is an onium salt such as a sulfonium salt or an iodonium salt, a diazo compound such as di (phenylsulfonyl) diazomethane or a substitution product thereof, 2, Benzyl tosylate such as 6-dinitrobenzyl tosylate, benzoin tosylate and triazine derivative are usually used.

Examples of such onium salts include:
The compounds shown in Chemical formulas 15 to 19 below can be mentioned.

[Chemical 15]

[Chemical 16]

[Chemical 17]

[Chemical 18]

[Chemical 19]

X in the above formula is p-toluenesulfonate anion, trifluoromethanesulfonate anion, hexafluoroantimonate anion, hexafluorophosphate anion, or tetrafluoroborate anion. Represents The content of onium salt in the resist material is 0.5 to 15% by weight.
It is preferably in the range of. If the content is less than 0.5% by weight, the sensitivity of the resist material cannot be improved,
When it is 15% by weight or more, the cost of the resist material increases and the mechanical strength of the resist film decreases.

The resist material of the present invention is obtained by dissolving these components in an organic solvent. The organic solvent at this time is preferably one in which the respective components are sufficiently dissolved and the resist film is evenly spread, and specifically, butyl acetate, xylene, acetone, cellosolve acetate, ethylene glycol monomethyl ether, diethylene glycol diethylene. Examples thereof include butyl ether, diethylene glycol dimethyl ether, ethyl lactate, methyl lactate, propyl lactate, butyl lactate, and propylene glycol methyl ether acetate.

Pattern formation on a substrate using the resist material of the present invention can be easily performed by the following method. That is, a resist material solution is spin-coated on a substrate and then pre-baked to obtain a coated substrate. When the obtained coated substrate is irradiated with a high energy ray, the acid generator in the coated film decomposes to generate an acid.

Then, when the substrate is exposed to heat and then heat-treated, the dissolution inhibitor and the t-butoxycarbonyloxy group of the poly (hydroxystyrene) resin are decomposed using the generated acid as a catalyst, and the dissolution inhibiting effect of the resist disappears. By doing so, a substrate having a latent image formed is obtained. next,
A positive type pattern can be formed by developing the substrate having the latent image with an alkaline aqueous solution and washing with water.

[0050]

INDUSTRIAL APPLICABILITY The bis-t-butoxycarbonylmethylthymolphthalein of the present invention exhibits a large solubility especially in a poly (hydroxystyrene) resin and a large dissolution inhibiting effect in an alkali developing solution, so that it has a poly (hydroxystyrene) content. When used as a dissolution inhibitor for a chemically amplified positive resist material using a resin, it is possible to sufficiently suppress the initial film loss of the resist film.

Further, the positive resist material using the above-mentioned dissolution inhibitor of the present invention has high sensitivity to high energy rays, particularly to deep ultraviolet rays having a short wavelength (KrF excimer laser, etc.), and also has a high sensitivity to the deep ultraviolet rays. Since it absorbs little, it is a resist material suitable for fine processing of substrates used in LSI and the like. In addition, the positive resist composition of the present invention does not contaminate the substrate because it does not contain a metal element, has little time dependence after exposure, and does not require moisture in the chemical amplification process, so that the process Is also a preferable positive resist material.

[0052]

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

Example 1. Thymolphthalein 25g
(0.058 mol), bromoacetate-t-butyl 25.
7 g (0.13 mol), tetra-n-butylammonium hydrogensulfate 1.25 g, and potassium carbonate 50 g (0.
36 mol) was suspended in 150 ml of dimethylsulfoxide and stirred at 60 ° C. for 6 hours for reaction. After allowing the reaction solution to cool, pour it into 300 ml of cold water to obtain 200 ml.
It was extracted twice with chloroform. The organic layer was washed with 300 ml of saturated saline and dried over anhydrous sodium sulfate, and then the solvent was distilled off. The obtained residue was purified by silica gel chromatography and recrystallized from hexane to obtain 29.4 g (yield 77%) of colorless prism crystals.

The melting point of the obtained prism crystals is 93 to 94.
It was ℃. Also, the measured value of ¹ HNMR (CDCl ₃ ) δ
Is 1.03 (6H, d), 1.68 (6H, d),
1.46 (18H, s), 3.25 (2H, m), 4.
51 (4H, s), 6.46 (2H, s), 6.84
(2H, s), 7.33 (1H, d), 7.55 (1
H, t), 7.69 (1H, t), 7.94 (1H,
d), which was confirmed to be bis-t-butoxycarbonylmethylthymolphthalein.

Example 2. Other than using t-butyl chloroacetate instead of t-butyl bromoacetate used in Example 1 and reacting by stirring at 60 ° C. for 12 hours,
When the synthesis was carried out in the same manner as in Example 1, the bis-
t-butoxycarbonylmethylthymolphthalein is 2
7.3 g (yield 72%) was obtained.

Example 3. 81 parts by weight of poly-p-hydroxystyrene (number average molecular weight 1.4 × 10 ⁻⁴ g / mol, molecular weight distribution 1.10), 14 parts by weight of bis-t-butoxycarbonylmethylthymolphthalein, diphenyl (p
-Methoxyphenyl) sulfonium trifluoromethane sulfonate (5 parts by weight) and diglyme (400 parts by weight) were mixed on a silicon substrate to form a resist solution.
Spin coating at 0 rev / min, 85 ℃ on hot plate
Pre-paque for 1 minute and the resist film thickness is 0.7μ
m resist coated substrate was obtained.

An accelerating voltage of 3 is applied to the coating side of the obtained coated substrate.
After drawing with an electron beam of 0 kV, heat treatment was performed at 85 ° C. for 2 minutes. Then, development was carried out for 1 minute using an aqueous solution of tetramethylammonium hydroxide (TMAH) 2.4% by weight, followed by washing with water for 30 seconds to obtain a silicone substrate (pattern substrate) on which patterns were formed. The obtained pattern of the substrate shows positive type characteristics, and the D ₀ sensitivity of the resist film is 3.
It was 6 μC / cm ² .

Further, instead of the electron beam, K which is far ultraviolet rays is used.
The D ₀ sensitivity when evaluated using rF excimer laser light (wavelength 248 nm) was 30 mJ / cm ² . Furthermore, the electron beam sensitivity was 2.5 μC / cm ² when the heat treatment after drawing was performed at 85 ° C. for 5 minutes. The resolution of the obtained pattern was 0.25 μm when an electron beam was used.

Examples 4-9. Instead of the onium salt diphenyl (p-methoxyphenyl) sulfonium fluoromethanesulfonate used in Example 3, the following Table 1 was used.
A resist solution was prepared in the same manner as in Example 3 except that the onium salt of Example 1 was used to obtain a resist-coated substrate.

[0060]

[Table 1]

The coated substrate obtained in each case was used in Example 3
Each pattern substrate was obtained by drawing with an electron beam in the same manner as in. The obtained patterns all showed positive characteristics, and the D ₀ sensitivity of the resist film was as shown in Table 1 above. Also, it was confirmed that the resolution of each pattern was 0.25 μm as in the case of Example 3.

Examples 10 to 16. Using the resist coated substrates obtained in Examples 3 to 9 and using soft X-rays (SR light) generated from a small superconducting ring as an exposure light source instead of the electron beam, A pattern substrate was obtained in exactly the same manner as in 3. The obtained patterns all showed positive characteristics, and the D ₀ sensitivity of the resist film was as shown in Table 2 below.
It was as shown in.

[0063]

[Table 2]

The sensitivity of each resist film is 50 mJ / c.
It was as high as m ² or less, and the resolution was 0.15 μm. These results show that with an exposure dose of 50 mJ / cm ² , 20 wafers of 6 inches can be produced per hour, and by using the resist of the present invention, photolithography can be performed even in X-ray lithography. It demonstrates that equal productivity can be ensured.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Jun Watanabe 3-2-1 Sakado, Takatsu-ku, Kawasaki City, Kanagawa Prefecture Corporate Research Center, Shin-Etsu Chemical Co., Ltd. (72) Minoru Takamizawa Sakado, Takatsu-ku, Kawasaki City, Kanagawa Prefecture 3-2-1, Shin-Etsu Chemical Co., Ltd. Corporate Research Center (72) Inventor, Keijun Tanaka 1-1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (3)

[Claims] 1. Bis-t-butoxycarbonylmethylthymolphthalein represented by the following chemical formula 1. [Chemical 1] 2. A bis-t-butoxycarbonylmethylthymolphthalein according to claim 1, wherein t-butoxycarbonyl α-haloacetic acid is reacted with thymolphthalein represented by the following chemical formula 2. Production method. [Chemical 2] 3. A poly (hydroxystyrene) resin a, a dissolution inhibitor b and an onium salt c are each added in a weight fraction of 0.5.
5 ≦ a, 0.07 ≦ b ≦ 0.40, 0.005 ≦ c ≦
A positive resist material containing 0.15 and a + b + c = 1 so that it can be developed with an aqueous alkaline solution and is sensitive to high energy rays, wherein the dissolution inhibitor b is the dissolution inhibitor b. Positive-type resist material, characterized in that it is bis-t-butoxycarbonylmethylthymolphthalein.