JPH07134416A - Radiation sensitive resin composition - Google Patents

Abstract

PURPOSE:To attain high sensitivity to radiation and high resolution by incorporating phenolic resin, sulfonic ester and an acid generating agent. CONSTITUTION:This radiation sensitive resin compsn. contains phenolic resin as a 1st component, sulfonic ester as a 2nd component and an acid generating agent as a 3rd component. The acid generating agent is a substance which is decomposed by the action of radiation such as light, electron beams, X-rays or ion beams and generates an acid. The phenolic resin acts as a matrix resin which dissolves in an aq. alkali soln. and the sulfonic ester inhibits the dissolution of the phenolic resin in the soln. This sulfonic ester forms naphthalene-2- sulfonic acid by a reaction with an acid catalyst and accelerates the dissolution of the alkali-soluble matrix resin. As a result, a significant difference in the velocity of dissolution is produced between the exposed and unexposed parts of a resist using this resin compsn.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel radiation-sensitive resin composition which can be used as a constituent material of a resist used for manufacturing a semiconductor device and is sensitive to radiation such as photoelectron beam, X-ray and ion beam. It is about.

[0002]

2. Description of the Related Art In recent years, submicron-order processing technology has become necessary with the high integration of LSIs.
For this reason, for example, in the etching process of LSI, a dry etching technique that enables highly precise and fine processing is adopted.

Here, the dry etching technique means that the substrate to be processed is covered with a resist, the resist is patterned by using light or an electron beam, and the obtained pattern is used as a mask to react the substrate with reactive gas plasma. This is a technique for etching the portion exposed from the mask. Therefore, the resist used in the dry etching technique needs to be made of a material having a resolution of submicron order and sufficient resistance to reactive gas plasma.

At present, a positive photoresist composed of a diazonaphthoquinone compound and a phenol novolac resin is widely used as a resist material used in the dry etching technique. Further, as the exposure apparatus, a reduction projection exposure apparatus using a g-line or an i-line of a mercury lamp is widely used. However, when performing fine processing with a size of half micron or less with high accuracy, a high resolution and a large focus margin that are higher than those of the current lithography technology used for dry etching technology are required. In order to meet this requirement, reduction projection exposure method using a short wavelength light source and electron beam exposure are indispensable. Therefore, various resist materials suitable for the lithography technique satisfying the above requirements have been studied, and various resist materials have been proposed.

For example, Document 1: "Japanese Patent Application Laid-Open No. 61-2402.
No. 37 gazette, "Deep U with a wavelength of less than 300 nm.
A technique using a resist composition for lithographic printing that can be used in V (deep UV) is disclosed. According to the technique disclosed in Document 1, trans-2-diazodecalin-1,3-
The resolution is improved by using a positive resist composed of a photosensitive solubilizer-like substance such as dione and an alkali-soluble matrix such as novolac resin. In Document 1, a line-and-space of 0.75 μm, for example, is printed by exposure to radiation of at least 150 mJ / cm ² .

Reference 2: "Japanese Patent Laid-Open No. 1-201654"
Japanese Patent Laid-Open Publication No. 2004-242242 discloses a technique using a radiation-sensitive polymer. According to the technique disclosed in Document 2, poly (p-
It is described that high resist contrast can be achieved by using acetoin ester of (styrene sulfonic acid) as a positive resist. In Document 2, for example, a resolution of 0.5 μm is achieved at 300 mJ / cm ² .

[0007]

By the way, when light in the deep UV region of a mercury lamp is used as a short-wavelength light source, the illuminance thereof is extremely low, so that a resist with extremely high sensitivity is required. Further, even when a KrF excimer laser is used as a short wavelength light source, a highly sensitive resist is required due to the attenuation of the light intensity in the reduction optical system.

Further, in the electron beam lithography, the pattern forming method is different from the photolithography, and the wafer surface is sequentially drawn by the electron beam, so that it cannot be put to practical use unless the sensitivity of the resist is high. Since the number of beam shots will increase remarkably as the degree of integration of semiconductor devices increases in the future, the requirement for the sensitivity of the resist becomes the most important factor together with the resolution.

However, since the above-mentioned conventional radiation-sensitive resin composition requires at least a considerable light exposure amount or electronic exposure amount for pattern formation, it is possible to sufficiently meet the above-mentioned requirement for resist sensitivity. There wasn't. In addition, as the degree of integration increases, a radiation-sensitive resin composition having a higher resolution has been required.

The present invention has been made in view of the above points, and therefore, an object of the present invention is to provide a novel radiation-sensitive resin composition having high sensitivity to radiation and high resolution. To provide.

[0011]

In order to achieve this object, according to the radiation-sensitive resin composition of the present invention, a phenol resin as the first component and a sulfonic acid as the second component are used. It is characterized by containing an ester and an acid generator as a third component. Here, the acid generator is a substance that decomposes by the action of radiation to generate an acid. The radiation includes light, electron beam, X-ray and ion beam.

The phenolic resin as the first component serves as a matrix resin which is soluble in an aqueous alkaline solution in the radiation-sensitive resin composition of the present invention (hereinafter also simply referred to as composition). As the phenol resin, for example, poly (hydroxystyrene) represented by the following formula (1) or novolac resin represented by the following formula (2) may be used.

[0013]

[Chemical 1]

The second component, sulfonic acid ester, is
It plays a role in suppressing the dissolution of phenolic resin in alkali. This sulfonic acid ester, for example, t-butyl naphthalene-2-sulfonate is reacted with an acid catalyst as shown in the following formula (3) to remove the t-butyl group to produce naphthalene-2-sulfonic acid. To do. This elimination reaction proceeds easily because the t-butyl cation produced from naphthalene-2-sulfonic acid is stable.
As the sulfonic acid ester having such an action, a tertiary alkyl group ester represented by the following formulas (a) to (c) is suitable, but in addition to this, various tertiary alkyl group esters represented by the following formulas (d) to (f) Α-alkylarylmethyl group ester of, various α, α-dialkylarylmethyl group ethers represented by the following formulas (to) to (i), or the following formulas (nu) to (wo)
Various α-alkyl-α-arylallylmethyl group esters shown in 1 may be used.

[0015]

[Chemical 2]

[0016]

[Chemical 3]

The naphthalene-2-sulfonic acid produced by the elimination reaction is a strong organic acid and promotes the dissolution of the alkali-soluble matrix resin. The phenolic hydroxyl group of the alkali-soluble matrix resin exhibits only extremely weak acidity, but the alkali-soluble (dissolution rate) of the phenol resin is remarkably increased by the formation of the strong organic acid. A large difference in dissolution rate occurs between the exposed and unexposed areas of the resist using the composition of the present invention. Therefore, the composition of the present invention provides a higher resolution resist.

Here, FIG. 1 shows a comparison diagram of the alkali dissolution rate of the phenol resin used in the radiation-sensitive resin composition of the present invention and the resist using the same. In Figure 1,
The dissolution rate of the phenol resin in the state where the hydroxyl group is not protected is (a), the dissolution rate of the unexposed portion of the resist using such a phenol resin is (b) and the dissolution rate of the exposed portion is (c), respectively. It shows relatively.

The naphthalene-2-sulfonic acid produced by the decomposition reaction of the sulfonic acid ester which is a dissolution inhibitor is a strong organic acid. Therefore, the generated naphthalene-2-sulfonic acid serves as a catalyst for the decomposition reaction and further decomposes the sulfonic acid ester, as shown in the following formula (4). As described above, the decomposition reaction of the dissolution inhibitor is also a growth reaction of an acid that serves as a catalyst for the decomposition reaction. Therefore, since the crosslinking reaction can be caused by a small amount of radiation, the composition of the present invention becomes a highly sensitive positive resist.

[0020]

[Chemical 4]

As the phenolic resin of the composition of the present invention, a phenolic resin whose hydroxyl groups are partially protected can be used. As such a phenol resin, for example, t-butoxycarbonate of poly (hydroxystyrene) represented by the following formula (5) or t-butoxycarbonate of novolak resin represented by the following formula (6) is used. Is also good. Phenol having a protected hydroxyl group has a large decrease in alkali solubility. On the other hand, such a phenol resin can be called a latent alkali-soluble resin because phenol dissolves in an alkaline aqueous solution in the state where the protective group is removed.

[0022]

[Chemical 5]

When a resist using a phenolic resin whose hydroxyl group is protected is irradiated with radiation, the acids generated from the acid generator and the sulfonate ester not only decompose the sulfonate ester, but also As shown in formula (7), the protective group of the phenol resin is also eliminated. Therefore, the alkali solubility (dissolution rate) of the phenol resin is remarkably increased due to the effects of acid generation, decomposition of the dissolution inhibitor and elimination of the protective group. As a result, a larger difference in dissolution rate occurs between the exposed area and the unexposed area than in the case of using phenol in which the hydroxyl group is not protected. Therefore, the composition of the present invention using the phenol having a partially protected hydroxyl group provides a resist having a higher resolution.

[0024]

[Chemical 6]

FIG. 2 shows a comparative diagram of the alkali dissolution rate of a phenol resin having a protected hydroxyl group and a resist using the same, which is used in the radiation-sensitive resin composition of the present invention. In FIG. 2, the dissolution rate of the phenolic resin in the state where the hydroxyl group is not protected is (a), the dissolution rate of the phenolic resin in the state where the hydroxyl group is protected is (d), and the dissolution rate of the resist using such a phenolic resin is shown. The dissolution rate of the exposed portion is shown by (e) and the dissolution rate of the exposed portion is shown by (f).

The acid that triggers the decomposition reaction of the above-mentioned sulfonic acid ester is supplied as a decomposition product by irradiation of the acid generator, which is the third component, with radiation. The acid generator used in the radiation-sensitive resin composition of the present invention must generate a strong acid. Examples of such compounds include various sulfonium salts represented by the following formulas (I) and (II), and the following formulas (III) and (I
V) various iodonium salts represented by the following formula (V)
The various p-toluene sulfonic acid ester represented by the formula (1) and the sulfonic acid ester represented by the following formula (VI) can be used.

[0027]

[Chemical 7]

However, X in the formulas (I) to (IV) is, for example, BF ₄ , AsF ₆ , SbF ₆ , ClO ₄ , CF ₃ S.
R ₃ in the formula (V) represents O ₃ and represents a group represented by the following formulas (A) and (B).

[0029]

[Chemical 8]

When poly (hydroxystyrene) is used as the phenolic resin which is the first component of the present invention,
For example, those having a relatively wide molecular weight distribution can be obtained from Maruzen Petrochemical Co., Ltd. Further, those having a narrow molecular weight distribution are described in, for example, the literature: “Polymer (Polymer).
r), 1983, vol. 24,995 ".
M. J. It can be easily synthesized by the method of Frechet et al. Further, when a novolac resin is used as the phenol resin, for example, the literature: “Journal of Electrochemical Society (J. El.
microchem. Soc. ), 129 , 201 (1
982) ”. It can be synthesized by the method of Gipstein et al. Further, t-butoxycarbonyl group and t-butyl group used as a protecting group are described in the literature: “Polymer, 1983, vo.
l. 24, 995]. M. J. Freche
It can be easily introduced by the method of T. et al.

The weight average molecular weight of the phenol resin used in the composition of the present invention is preferably 500 to 100,000. When the weight molecular weight is less than 500, the resist film containing this composition becomes sticky and particles (dust in the air) are easily attached to the film. On the other hand, if the weight molecular weight is larger than 100,000,
Since the solubility in a solvent decreases, coating unevenness is likely to occur when a resist containing this composition is applied.

The addition amount of the sulfonic acid ester which is the second component of the present invention to the phenol resin is 0.
It is preferably in the range of 05 to 50 mol%. If the amount added is less than 0.05 mol%, the sensitivity of the composition to radiation is reduced, and as a result, the resolution of the composition is reduced. On the other hand, if the addition amount is larger than 50 mol%,
The thermal stability of a resist film containing this composition is deteriorated, and uneven coating is likely to occur when a resist containing this composition is applied. Also, of the hydroxyl groups of phenol,
The proportion of hydroxyl groups protected is preferably in the range of 5% to 80%. When the protected ratio is less than 5%, a sufficient difference in dissolution rate between the unexposed portion and the exposed portion cannot be taken when the amount of the sulfonate ester and the acid generator is small. As a result, the pattern shape of the resist using the composition of the present invention deteriorates. On the other hand, 8 splitting agents are protected
If it is larger than 0%, a poorly soluble layer may be formed on the surface of the resist during pattern formation, and the resist in the region to be the opening of the pattern may not be removed.

As the acid generators represented by the formulas (I) to (VIII), those supplied from Midori Kagaku Co., Ltd. can be used. Alternatively, the document “Journal of Polymer Science, Polymer, Chemistry Edition (J. Polymer Science)
e, Polymer Chem. Ed,). 18, 26
77 (1980) ". It can also be synthesized by the method of Crivero et al.

The addition amount of the acid generator as the third component of the present invention to the phenol resin is 0.005 to 2
It is preferably in the range of 0 mol%. Addition amount is 0.
If it is less than 005 mol%, the composition becomes less sensitive to radiation and, as a result, the resolution of the composition decreases. On the other hand, when the addition amount is larger than 20 mol%, the thermal stability of the resist film containing this composition is deteriorated, and coating unevenness is likely to occur when a resist containing this composition is applied.

[0035]

EXAMPLES Examples of the radiation-sensitive resin composition of the present invention will be described below. Numerical conditions such as the materials used and the amounts thereof, the processing time, the processing temperature, and the film thickness mentioned in the following description are only suitable examples within the scope of the present invention. Therefore, the present invention is not limited to these conditions.

First Embodiment The first embodiment will be described below. In the first embodiment,
As the first component, a molecular weight of 11,500 and a molecular weight dispersion of 1.
1.2 g of poly (hydroxystyrene) of 23, t-butyl naphthalene sulfonate as the second component 132 m
g, as a third component, triphenylsulfonium triflate (in the formula (I), X is CF ₃ SO ₃ ).
A resist solution is prepared by dissolving 20.6 mg of each in 6.0 ml of cyclohexanone as a solvent.

The amount of t-butyl naphthalene sulfonate used in the first example, 132 mg, was 1.2 g of poly (hydroxystyrene), and the molecular weight was 12 in terms of monomer units.
This corresponds to 5.0 mol% with respect to 0. In addition, 20.6 mg of triphenylsulfonium triflate has a molecular weight of 12 g of a phenol resin 1.2 g in terms of a monomer unit.
This corresponds to 0.5 mol% with respect to 0.

Next, a resist solution is spin-coated on a silicon substrate which has been subjected to HDMS treatment (exposure to hexamethyl disilazane vapor),
Baking is performed on a hot plate at a temperature of 110 ° C. for 2 minutes to form a resist layer having a film thickness of 0.6 μm. Next, a test pattern is drawn on the resist layer with an electron beam with an acceleration voltage of 20 kV using ELS3300 (trade name) manufactured by Elionix. The exposure dose at this time is 0.56 μC
/ Cm ² . Then, the silicon substrate on which the test pattern was drawn was baked on a hot plate at a temperature of 90 ° C. for 2 minutes, developed with a 0.27 N (normal) tetramethylammonium (TMAH) solution for 20 minutes, and then purified with pure water. Rinse for 5 minutes. The pattern obtained in this way is scanned with an electron microscope (SEM) (Hitachi, S6000 length measurement S
When observed with EM (trade name), it was confirmed that a line and space of 0.3 μm could be resolved.

Second Embodiment The second embodiment will be described below. In the second embodiment,
As the first component, a molecular weight of 11,500 and a molecular weight dispersion of 1.
Poly (hydroxystyrene) of 23 g, tert-butyl 4-toluenesulfonate (formula (b)) 228 mg as the second component, benzoyl- as the third component.
A resist solution is prepared by dissolving 36.5 mg of p-toluenesulfonate (formula (V)) in 6.0 ml of cyclohexanone as a solvent.

The added amount of 228 mg of t-butyl 4-toluenesulfonate used in the second embodiment is 1 g of the molecular weight of 1.2 g of poly (hydroxystyrene) in terms of monomer units.
This corresponds to 10 mol% with respect to 20. Further, 36.5 mg of benzoyl-p-toluenesulfonate has a molecular weight of 12 g of phenol resin 1.2 g in terms of monomer unit.
This corresponds to 1.0 mol% with respect to 0.

Next, a resist solution was spin-coated on a HMDS-treated silicon substrate to enhance adhesion with the resist, and baked on a hot plate at a temperature of 110 ° C. for 2 minutes to give a film thickness. Form a 0.6 micron resist layer. Next, a test pattern is drawn on the resist layer with an electron beam with an acceleration voltage of 20 kV using ELS3300 (trade name) manufactured by Elionix. The exposure dose at this time is 0.35 μC / cm ² . Next, the silicon substrate on which the test pattern was drawn was baked on a hot plate at a temperature of 90 ° C. for 2 minutes, and then 0.27N TMAH was used.
Develop with solution for 20 minutes and rinse for 5 minutes. The pattern thus obtained is SEM (Hitachi, S6000 length measurement S
When observed with EM (trade name), it was confirmed that a line and space of 0.3 μm could be resolved.

Third Embodiment The third embodiment will be described below. In the third embodiment,
As the first component, a molecular weight of 11,500 and a molecular weight dispersion of 1.
Poly (hydroxystyrene) of 23 g, t-butyl naphthalenesulfonate (formula (a)) 264 mg as the second component, triphenylsulfonium triflate (in formula (I), X Is CF ₃ S
O. ₃ ) (4.1 mg) is dissolved in 6.0 ml of cyclohexanone, which is a solvent, to prepare a resist solution.

The addition amount of t-butyl naphthalene sulfonate used in the third example of 2642 mg was 1.2 g of poly (hydroxystyrene), and the molecular weight was 1 in terms of monomer unit.
This corresponds to 10 mol% with respect to 20. In addition, 4.1 mg of triphenylsulfonium triflate has a molecular weight of 120 g of phenol resin 1.2 g in terms of monomer unit.
Corresponding to 0.1 mol%.

Next, a resist solution is spin-coated on a HDMS-treated silicon substrate, and the resist solution is placed on a hot plate for 11 minutes.
Baking at a temperature of 0 ° C for 2 minutes to give a film thickness of 0.6
A micron resist layer is formed. Next, an electron beam with an accelerating voltage of 20 kV was applied to the resist layer by ELS3 manufactured by Elionix.
A test pattern is drawn using 300 (product name).
The exposure dose at this time is 0.15 μC / cm ² . next,
After baking the silicon substrate on which the test pattern was drawn on a hot plate at a temperature of 90 ° C. for 2 minutes,
Develop with 104 N TMAH solution for 20 minutes and rinse for 5 minutes. When the pattern thus obtained was observed by SEM (Hitachi, S6000 length measurement SEM (trade name)), it was confirmed that a line and space of 0.3 μm could be resolved.

Fourth Embodiment The fourth embodiment will be described below. In the fourth embodiment,
The first component has a molecular weight of 8500 and a molecular weight dispersion of 3.5.
0-1.2 g of p-cresol novolac resin, 264 mg of t-butyl naphthalene sulfonate (formula (I)) as the second component, and 36 mg of pyrogallol trimethanesulfonate ((VI)) as the third component, respectively. Is dissolved in 6.0 ml of cyclohexanone to prepare a resist solution.

The addition amount of 264 mg of t-butyl naphthalene sulfonate used in the first embodiment is 1 g of the molecular weight of 1.2 g of p-cresol novolac resin in terms of monomer unit.
This corresponds to 10 mol% with respect to 20. In addition, 36 mg of pyrogallol trimethanesulfonate corresponds to 1.0 mol% with respect to the molecular weight 120 of 1.2 g of p-cresol novolac resin in terms of monomer units.

Next, a resist solution is spin-coated on a HDMS-treated silicon substrate, and a hot plate is used for 90 minutes.
Baking is performed at a temperature of ℃ for 2 minutes to form a resist layer having a film thickness of 0.6 micron. Next, an electron beam with an accelerating voltage of 20 kV was applied to the resist layer by ELS33 manufactured by Elionix.
A test pattern is drawn using 00 (product name). The exposure amount at this time is 0.80 μC / cm ² . Next, the silicon substrate on which the test pattern was drawn was baked on a hot plate at a temperature of 90 ° C. for 2 minutes, and then 0.2
Develop with 7N TMAH solution for 20 minutes and rinse for 5 minutes. The pattern thus obtained is SEM (Hitachi, S
When observed with a 6000 length measuring SEM (trade name),
It was confirmed that the line and space of 0.3 μm could be resolved.

In the following, in the fifth to eighth examples, examples using a phenol resin in which hydroxyl groups are partially protected will be described.

Fifth Embodiment The fifth embodiment will be described below. In the fifth embodiment,
The first component has a molecular weight of 14400 and a molecular weight dispersion of 1.
26, 1.2 g of partially t-butoxycarbonylated poly (hydroxystyrene) (protection rate 30%), and as the second component, t-butyl naphthalene-2-sulfonate 132 m
g, as a third component, triphenylsulfonium triflate (in the formula (I), X is CF ₃ SO ₃ ).
A resist solution is prepared by dissolving 20.6 mg of each in 6.0 ml of cyclohexanone as a solvent.

The amount of t-butyl naphthalene sulfonate used in the fifth example, 132 mg, was 5.0 mol with respect to the molecular weight 153 of 1.2 g of partially t-butoxycarbonylated poly (hydroxystyrene) as a monomer unit.
Equivalent to%. Further, 20.6 mg of triphenylsulfonium triflate corresponds to 0.5 mol% based on the molecular weight 120 of 1.2 g of partially t-butoxycarbonylated poly (hydroxystyrene) in terms of monomer units.

Next, a resist solution is spin-coated on a HDMS-treated silicon substrate, and the resist solution is placed on a hot plate.
Baking at a temperature of 0 ° C for 2 minutes to give a film thickness of 0.6
A micron resist layer is formed. Next, an electron beam with an accelerating voltage of 20 kV was applied to the resist layer by ELS3 manufactured by Elionix.
A test pattern is drawn using 300 (product name).
The exposure dose at this time is 0.56 μC / cm ² . next,
After baking the silicon substrate on which the test pattern was drawn on a hot plate at a temperature of 90 ° C. for 2 minutes,
Develop with a 27N TMAH solution for 20 minutes and rinse with pure water for 5 minutes. When the pattern thus obtained was observed with a scanning electron microscope (SEM) (Hitachi, S6000 length measurement SEM (trade name)), it was confirmed that a line and space of 0.3 μm could be resolved.

Sixth Embodiment The sixth embodiment will be described below. In the sixth embodiment, the first component has a molecular weight of 14400 and a molecular weight dispersion of 1.2.
1.2 g of partially t-butoxycarbonylated poly (hydroxystyrene) (protection rate 30%) of 6 and t-butyl 4-toluenesulfonate (formula (II)) 2 as the second component
28 mg, as a third component, benzoyl-p-toluenesulfonate (wherein R of the formula (V) is (A)) 3
Cyclohexanone (6.5 mg) was used as a solvent.
Dissolve in 0 ml to prepare a resist solution.

The amount of 228 mg of t-butyl 4-toluenesulfonate used in the sixth example was 10 mol with respect to the molecular weight 153 of 1.2 g of partially t-butoxycarbonylated poly (hydroxystyrene) as a monomer unit.
Equivalent to%. In addition, 36.5 mg of benzoyl-p-toluenesulfonate corresponds to 1.0 mol% with respect to the molecular weight 153 of 1.2 g of partially t-butoxycarbonylated poly (hydroxystyrene) as a monomer unit.

Next, a resist solution is spin-coated on a HDMS-treated silicon substrate, and the resist solution is placed on a hot plate.
Baking at a temperature of 0 ° C for 2 minutes to give a film thickness of 0.6
A micron resist layer is formed. Next, an electron beam with an accelerating voltage of 20 kV was applied to the resist layer by ELS3 manufactured by Elionix.
A test pattern is drawn using 300 (product name).
The exposure dose at this time is 0.25 μC / cm ² . next,
After baking the silicon substrate on which the test pattern was drawn on a hot plate at a temperature of 90 ° C. for 2 minutes,
Develop with a 27N TMAH solution for 20 minutes and rinse with pure water for 5 minutes. When the pattern thus obtained was observed by SEM (Hitachi, S6000 length measurement SEM (trade name)), it was confirmed that a line and space of 0.3 μm could be resolved.

Seventh Embodiment The seventh embodiment will be described below. In the seventh embodiment,
The first component has a molecular weight of 8500 and a molecular weight dispersion of 3.5.
No. 0 p-cresol novolac resin 1.2 g, as a second component, t-butyl naphthalene-2-sulfonate (formula (a)) 264 mg, and as a third component, trephenylsulfonium triflate (in formula ()) , X is CF ₃ SO
₃ mg) (4.1 mg) is dissolved in 6.0 ml of cyclohexanone, which is a solvent, to prepare a resist solution.

The addition amount of 264 mg of t-butyl naphthalene-2-sulfonate used in Example 7 corresponds to 10 mol% with respect to the molecular weight 153 of 1.2 g of p-cresol novolac resin in terms of monomer unit. In addition, 4.1 mg of trephenylsulfonium triflate is p
-Corresponding to 0.1 mol% with respect to the molecular weight 153 of 1.2 g of cresol novolac resin in terms of monomer units.

Next, a resist solution was spin-coated on a HMDS-treated silicon substrate to enhance adhesion with the resist, and baked on a hot plate at a temperature of 110 ° C. for 2 minutes to give a film thickness. Form a 0.6 micron resist layer. Next, a test pattern is drawn on the resist layer with an electron beam with an acceleration voltage of 20 kV using ELS3300 (trade name) manufactured by Elionix. The exposure dose at this time is 0.15 μC / cm ² . Next, the silicon substrate on which the test pattern was drawn was baked on a hot plate at a temperature of 90 ° C. for 2 minutes, and then 0.27N TMAH was used.
Develop with solution for 20 minutes and rinse for 5 minutes. The pattern thus obtained is SEM (Hitachi, S6000 length measurement S
When observed with EM (trade name), it was confirmed that a line and space of 0.3 μm could be resolved.

Eighth Embodiment The eighth embodiment will be described below. In the eighth embodiment,
3. As the first component, molecular weight 10650, molecular weight dispersion 4.
No. 00 p-cresol novolac resin 1.55 g, second
As a component of t-butyl naphthalene-2-sulfonate (formula (i)) 264 mg, and as a third component, pyrogallol trimethanesulfonate (formula (VI) 36 mg are dissolved in 6.0 ml of cyclohexanone as a solvent, respectively. Prepare a resist solution.

The addition amount of 264 mg of t-butyl naphthalene-2-sulfonate used in the eighth example corresponds to 10 mol% with respect to the molecular weight 153 of p-cresol novolac resin 1.55 g in terms of monomer unit. Also,
Pyrogallol trimethanesulfonate 36 mg is p-
This corresponds to 1.0 mol% based on the molecular weight 153 of the cresol novolac resin 1.55 g in terms of the monomer unit.

Next, a resist solution was spin-coated on a HMDS-treated silicon substrate to enhance adhesion with the resist, and baked on a hot plate at a temperature of 110 ° C. for 2 minutes to give a film thickness. Form a 0.6 micron resist layer. Next, a test pattern is drawn on the resist layer with an electron beam with an acceleration voltage of 20 kV using ELS3300 (trade name) manufactured by Elionix. The exposure amount at this time is 1.00 μC / cm ² . Next, the silicon substrate on which the test pattern was drawn was baked on a hot plate at a temperature of 90 ° C. for 2 minutes, and then 0.27N TMAH was used.
Develop with solution for 20 minutes and rinse for 5 minutes. The pattern thus obtained is SEM (Hitachi, S6000 length measurement S
When observed with EM (trade name), it was confirmed that a line and space of 0.3 μm could be resolved.

[0061]

The radiation-sensitive resin composition of the present invention comprises
As a first step, the acid generator in the composition is decomposed by irradiation to generate a strong acid. In the second step, the strong acid decomposes the sulfonic acid ester, which is a dissolution inhibitor of the phenol resin, to generate sulfonic acid. Since this sulfonic acid is a strong acid, it further promotes the decomposition reaction of the sulfonic acid ester. As a result, the solubility of the phenol resin in the exposed area is significantly increased. Therefore, a large difference in dissolution rate occurs between the unexposed area and the exposed area, so that high resolution can be obtained.

Furthermore, the reaction in the second stage is an acid-catalyzed reaction, and in the composition of the present invention, the sulfonic acid produced from the sulfonic acid ester also works effectively as a catalyst.
Therefore, a small dose of radiation is required, and the composition of the present invention becomes a highly sensitive positive resist.

Further, for example, as a phenol resin,
When a phenolic resin whose hydroxyl groups are partially protected is used, the acid generated from the acid generator and the sulfonic acid generated from the sulfonic acid ester further decomposes the sulfonic acid ester and releases the protective group of the phenolic resin. . Therefore, the alkali solubility of the phenol resin is significantly increased by the generation of acid, the decomposition of the dissolution inhibitor and the elimination of the protective group. As a result, a larger difference in dissolution rate occurs between the exposed area and the unexposed area than in the case of using a phenol resin in which the hydroxyl group is not protected. Therefore, the composition of the present invention using the phenolic resin in which the hydroxyl groups are at least partially protected becomes a resist with higher resolution.

Therefore, the composition of the present invention can be used for manufacturing a semiconductor device without lowering the throughput even when exposing a resist using an electron beam or deepUV of a mercury lamp as a light source. Further, since the radiation-sensitive resin composition of the present invention can be developed with an alkali developing solution, it has good compatibility with the existing resist process.

[Brief description of drawings]

FIG. 1 is a comparison diagram of alkali dissolution rates of a phenol resin used in a radiation-sensitive resin composition of the present invention and a resist using the same.

FIG. 2 is a comparison diagram of alkali dissolution rates of a hydroxyl group-protected phenol resin used in the radiation-sensitive resin composition of the present invention and a resist using the same.

[Explanation of symbols]

(A): Dissolution rate of phenolic resin not protected by hydroxyl group (b): Dissolution rate of resist unexposed area (c): Dissolution rate of resist exposed area (d): Dissolution rate of phenolic resin protected by hydroxyl group (E): Dissolution rate of resist unexposed area (f): Dissolution rate of resist exposed area

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H01L 21/027

Claims (9)

[Claims] 1. A radiation-sensitive resin composition comprising a phenol resin, a sulfonic acid ester and an acid generator. 2. The radiation-sensitive resin composition according to claim 1, wherein the phenol resin is poly (hydroxystyrene). 3. The radiation-sensitive resin composition according to claim 1, wherein the phenol resin is a novolac resin. 4. The radiation-sensitive resin composition according to claim 1, wherein the phenol resin has a weight average molecular weight of 500 to 10.
A radiation-sensitive resin composition, which is in the range of 0000. 5. The radiation-sensitive resin composition according to claim 1, wherein the addition amount of the sulfonic acid ester to the poly (hydroxystyrene) is in the range of 0.05 to 50 mol%. Radiation-sensitive resin composition. 6. The radiation-sensitive resin composition according to claim 1, wherein the amount of the acid generator added to the poly (hydroxystyrene) is in the range of 0.005 to 20 mol%. Radiation-sensitive resin composition. 7. The radiation-sensitive resin composition according to claim 1, wherein the hydroxyl group of the phenol resin is protected by a protective group. 8. The radiation-sensitive resin composition according to claim 7, wherein the protective group is a t-butoxycarbonyl group or a t-butyl group. 9. The radiation-sensitive resin composition according to claim 7, wherein among the hydroxyl groups of the phenol resin,
The proportion of hydroxyl groups protected by the protecting group is 5 to
A radiation-sensitive resin composition, which is in the range of 80%.