JPH02106751A - Pattern forming material - Google Patents

Abstract

PURPOSE:To easily obtain the fine pattern with a submicron order of the subject material by composing the pattern forming material of a photosensitive compd. capable of producing sulfonic acid with the exposure of KrF excimer laser rays, a resin and a solvent soluble to the photosensitive compd. and the resin. CONSTITUTION:The pattern forming material is composed of the photosensitive compd. capable of producing sulfonic acid by being released a diazo group with the exposure of the KrF excimer laser rays, the resin and the solvent soluble to the compd. and the resin. As sulfuric acid has a strong acidity than carboxylic acid, the dissolving speed of the material to a developer is increased, and the sensitivity of the material incorporated the photosensitive compd. is improved. The releasing reaction of a diazo group progresses with further good efficiency in acidic surroundings, and with good efficiency in the surroundings of the sulfonic acid having a strong acidity. Thus, the sensitivity of the pattern forming material is improved, and the submicron pattern of the material is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to pattern forming materials used in manufacturing semiconductor devices, etc.
This invention relates to a pattern forming material for forming a positive pattern using an 8.4 nm KrF excimer laser, deep ultraviolet rays, etc.

Conventional technology In recent years, as semiconductor devices have become more densely integrated, the wavelengths used by exposure equipment used for photolithography even during microfabrication have become increasingly shorter, and now KrF excimer lasers (248.4 nm) are being considered. It's getting to that point. However, there has not yet been a suitable pattern forming material for wavelengths 6 to -7.

There is a pattern forming material (for example, MP2400 manufactured by Nijiplay Co., Ltd.) consisting of a photosensitive agent and a novolac resin in which the absorption wavelength of naphthoquinone diazizo, which is a conventional photosensitive compound, is shifted to the shorter wavelength side. A pattern forming method using a conventional pattern forming material will be explained in detail with reference to FIG. A pattern forming material 5 is spin-coated onto a substrate 1 such as a semiconductor, and a thickness of 1.0μ is applied.
A resin film of m is obtained (Fig. 3a). Note that an oxide film, an insulating film, a conductive film, etc. are often formed on the substrate 1. Next, pulse exposure is performed using a 248.4 nm KrF ekin laser 3 through a mask 4 (FIG. 3b).

Finally, development is performed using an ordinary alkaline aqueous solution to dissolve and remove the exposed portion 60 of the pattern forming material 6, thereby obtaining a resist pattern 5a (FIG. 3C).

Problems to be Solved by the Invention However, the resist pattern 6a is deteriorated compared to the ideal resist pattern 8 and has large film loss.
A good pattern cannot be expected.

Therefore, a material having a good response to KrF excimer laser was proposed. In photosensitive compounds having the above bond, the photoreaction is a main chain cleavage reaction accompanied by elimination of the diazo group, and therefore no improvement in sensitivity can be expected.

The reason why the pattern shape of the resist made of naphthoquinone cyanovolac resin deteriorates is as shown in Figure 4.
The transmittance of 248.4 nm is only a few percent and hardly improves even after exposure, so a large exposure amount is required to expose the bottom of the resist, and even the parts that should originally be unexposed are exposed. This is to put it away. A resist made of polyurethane resin exhibits good fading property against light of 248.4 nm, but the fading rate is low because the reaction process is based on main chain cleavage due to elimination of the diazo group. Therefore, the present invention The purpose of the present invention was to obtain a pattern forming material that exhibits good fading resistance to KrF excimer laser and has improved sensitivity.

Means for Solving the Problems The present invention provides a photosensitive compound and a resin that generate sulfonic acid upon elimination of a diazo group upon exposure to a KrF excimer laser;
and a pattern forming material comprising a solvent capable of dissolving both.

Function: A photosensitive compound that generates sulfonic acid upon exposure to KrFz ximer laser becomes soluble in the exposed area in an alkaline developer. This point is similar to the mechanism by which conventional photosensitive compounds generate carboxylic acids, but since sulfonic acids are more acidic (lower pH) than carboxylic acids, their dissolution rate in the developer improves, The patterning material used has improved sensitivity. Furthermore, it is well known that the elimination reaction of diazo groups occurs more efficiently in an acidic atmosphere.

The elimination reaction of the diazo group proceeds efficiently in an atmosphere of nulphonic acid, which is more acidic than conventional carboxylic acids. From this point of view, a pattern forming material using the above-mentioned photosensitive compound A can be expected to have improved sensitivity.

The present inventors have synthesized and studied various photosensitive groups whose diazo group is eliminated to generate sulfonic acid upon exposure to KrF excimer laser, and have found that the following photosensitive group satisfies the above conditions.

Note that the present invention is not limited to the above photosensitive groups.

The cydiazo group of the photosensitive group is removed by exposure to a KrF excimer laser, and the bond between the carbon atom and the sulfur atom is accordingly broken. This is due to moisture in the pattern forming material or
It reacts with the monoα group in the alkaline aqueous solution that is the developer to form sulfonic acid and becomes alkali-soluble. That is, the pattern forming material of the present invention exhibits a positive type in which the exposed portion dissolves.

However, in general, the main polymer of the resist is 7) v-potassium soluble novolak resin. Therefore, it is desirable to be able to suppress the alkali solubility of the resin.

In the resist of the present invention, -5o is added to the terminal of the photosensitive compound.
2ca, i* having a functional group such as 15O3H9-8O3cH3 can form an ester bond with the 10H group, which is the alkali-soluble part of the resin, and can suppress the alkali solubility of the resin. In particular, when the molecule has two or more of the above-mentioned functional groups, the above-mentioned ester reaction occurs at two or more places in one molecule, and the crosslinking reaction progresses, resulting in an increase in molecular weight, which further suppresses the solubility of the resin. Can be done.

In addition, in the photosensitive compound used in the present invention, -5o2
Cβ.

The functional group such as -8○3H9-8o3cH3 may be located at either the benzene ring or the naphthalene ring, and there is no difference in the effect as a photosensitizer in either case.

Furthermore, in order to obtain a good pattern, it is essential that the suction strength at 248.4 nm has a large difference due to deep UV exposure.

In the photosensitive compound used in the resist of the present invention, 11
-Those in which substituents other than hydrogen atoms such as -CH3, -CH2CH3, -8o2C1 are added to the benzene ring, those in which a naphthalene ring is used in place of this, and those in which the above substituents are added to the naphthalene ring. The absorption of the benzene ring, which normally has a peak around 25 Onm, was shifted to the higher wavelength side by 20 to 70 nm, and as a result, the transmittance at 248.4 nm was improved by 10 to 30% both before and after exposure.

Note that the substituents such as -CH3, -CH2CH3, -8o2Cl, etc. may be placed at any position in the benzene ring, and the inventors have confirmed that the transmittance is improved in any case.

EXAMPLES The present invention will be explained in more detail using examples below.
The present invention is not limited in any way by these.

(Example 1) A reagent was prepared with the following composition and used as a pattern forming material.
(abbreviated as IME) 30g A pattern forming method using the pattern forming material according to the present invention will be described with reference to FIG. A pattern forming material 2 dissolved in the above composition is spin-coated onto a substrate 1 such as a semiconductor substrate to obtain a resist film of 1.0 μm (FIG. 1a). Note that there is an oxide film on the substrate 1.

In many cases, an insulating film, a conductive film, etc. are formed.

Next, a mask 4 is exposed using a 248.4 nm excimer laser beam 3.
(FIG. 1b). Finally, development was carried out using an ordinary alkaline developer, and only the light exposed portions 20 of the pattern forming material 2 were dissolved and removed to obtain a resinous pattern 2a (FIG. 1C).

At this time, the anubect ratio of resinut pattern 2a is 9.
With a good shape of o degree, about 40
Bakun formation was possible with a small exposure dose of mJ, and the film thickness was also 6.6 with a submicron pattern of 10 inches or less.

Ultraviolet spectroscopy before and after exposure of this pattern forming material! The curve diagram is shown in Fig. 6, and 1 at 248.4 nm.
3. The transmittance before and after exposure was 6 and 85, respectively, and the amount of change was as large as about 80%. That is, it can be seen that this photosensitive material and the photosensitive compound of the present invention showed good reactivity to KrF excimer laser light.

(Example 2) A reagent was prepared with the following composition and used as a pattern forming material.

14/, -7 Novolac resin 7gDIGDI
Experiments similar to Examples 1 and 2 were conducted using 30 g of ME. The results are from Example 1 to
A good product similar to 2 was obtained.

(Example 4) A reagent was prepared with the following composition and used as a pattern forming material.

Novolac resin 7yDIGDI
ME 307 The same experiment as in Example 1 was conducted using this.

The results were as good as in Example 1.

(Example 3) A reagent was prepared with the following composition and used as a pattern forming material.

Novolac resin 7gD I G
Experiments similar to Examples 1 to 3 were conducted using 30 g of DIME. The results were as good as in Examples 1-3.

(Example 5) A reagent was prepared with the following composition and used as a pattern forming material.

CH2CH3SC"+OH-ΣcH33FJ15 ・Novolac resin 7gDIGD
Experiments similar to Examples 1 to 4 were conducted using IME 30J. The results were as good as those in Examples 1 to 4.

(Example 6) A reagent was prepared with the following composition and used as a pattern forming material.

g Novolac resin 7gDIGDI
Experiments similar to Examples 1 to 5 were conducted using 30 g of ME. The results are from Example 1 to
A good product similar to No. 5 was obtained.

(Example 7) A reagent was prepared with the following composition and used as a pattern forming material.

Novolac resin 7gDIGDI
Experiments similar to Examples 1 to 6 were conducted using 30 g of ME. The results are from Example 1 to
A good product similar to that of Example 6 was obtained.

(Example 8) A reagent was prepared with the following composition and used as a pattern forming material.

CHCH33g 17, novolak resin 7gDIGDI
ME 3o9 Using this, experiments similar to Examples 1 to T were conducted. The results are from Example 1 to
Good results similar to those obtained were obtained.

(Example 9) A reagent was prepared with the following composition and used as a pattern forming material.

5o2Ct 3g Novolac resin 7gDIGD
IME 3o9 Experiments similar to Examples 1 to 8 were conducted using this. The results were as good as in Examples 1-8.

(Example 1o) Prepare the reagent with the following composition and add it to the pattern forming material in step 18. did.

Novolac resin 7gD I
GD IME so9 Experiments similar to Examples 1 to 9 were conducted using this. The results were as good as in Examples 1-9.

(Example 11) A reagent was prepared with the following composition and used as a pattern forming material.

novolak resin DIGDIME Examples 1 to 1 using this became. The result is Example 1 g g 30.9 Perform the same experiment as 0. Good as ~10 19・ I got something.

(Example 12) Prepare the reagent with the following composition and apply it. did.

Forming material and ○g Novolac resin 7gDIGD
IME 309 Using this, experiments similar to Examples 1 to 11 were conducted. The results were as good as those of Examples 1 to 11.

(Example 13) A reagent was prepared with the following composition and used as a pattern forming material.

Novolac resin g DIGDIME 30 g Using this, the same experiments as in Examples 1 to 12 were conducted. The results were as good as those of Examples 1 to 12.

(Example 14) A reagent was prepared with the following composition and used as a pattern forming material.

g Novolac resin 7gD I
GD IME 309 Using this, experiments similar to Examples 1 to 13 were conducted. The results were as good as those of Examples 1 to 13.

(Example 15) A reagent was prepared with the following composition and used as a pattern forming material.

217, g Novolak resin 7gDIGD
Experiments similar to Examples 1 to 14 were conducted using 30 g of IME. The results were as good as those of Examples 1 to 14.

(Example 16) A reagent was prepared with the following composition and used as a pattern forming material.

novolak resin DIGDIME Examples 1 to 1 using this became. The result is Example 1 g g 0g Perform the same experiment as in 5. ~ As good as 15 To 22-2 I got something.

(Example 17) A reagent was prepared with the following composition and used as a pattern forming material.

g Novolac resin 7gDIGDI
ME 30,9 Using this, experiments similar to Examples 1 to 16 were conducted. The results were as good as those in Examples 1 to 16. (Example 18) A reagent was prepared with the following composition and used as a pattern forming material.

g 23, novolac resin 7g D I G
DIME 30. ! Experiments similar to Examples 1 to 17 were conducted using i+. The results were as good as those of Examples 1 to 17.

(Example 19) A reagent was prepared with the following composition and used as a pattern forming material.

g Novolac resin 7gDIGDI
Experiments similar to Examples 1 to 18 were conducted using 30 g of ME. The result is Example 1
A good product similar to that obtained in Example 1-18 was obtained.

(Example 20) A reagent was prepared with the following composition and used as a pattern forming material.

g Novolac resin 7gDIGD
IME 30.9 Using this, experiments similar to Examples 1 to 19 were conducted. The results were as good as those of Examples 1 to 19.

(Example 21) A reagent was prepared with the following composition and used as a pattern forming material.

g Novolac resin 7gDIGD
IME 3o9 Using this, experiments similar to Examples 1 to 20 were conducted.25. The results were as good as in Examples 1-20.

(Example 22) A reagent was prepared with the following composition and used for pattern formation.

261, Novolac resin 7gDIGDI
Experiments similar to Examples 1 to 22 were conducted using 3og of ME. The result is Example 1
A good product similar to that obtained in Example 2-22 was obtained.

(Example 24) A reagent was prepared with the following composition and used as a pattern forming material.

g Novolac resin 7gDIGD
Experiments similar to Examples 1 to 21 were conducted using IME sog. The results were as good as in Examples 1-21.

(Example 23) A reagent was prepared with the following composition and used as a pattern forming material.

g Novolac resin 7gDIGD
Experiments similar to Examples 1 to 23 were conducted using 30 g of IME. The results were as good as those in Examples 1-23.

Note that the resin in the pattern forming material is required to be highly transparent to far ultraviolet light such as 248.4 nm in order to reduce surface absorption of the photosensitive material.

2.7, -5 In addition to the novolak resin used in Examples 1 to 8o, maleimide MmllL styrene maleic acid half N.T.
Similar results can be obtained by using LD-hydroxynutylene resin, or-1-chloromethocresol novolanc resin, but the present invention is not limited to these, of course.

Similar transparency is desired for the solvent, and in this example diethylene glycol dimethyl ether, which has low absorption in the deep ultraviolet region, was used, but if the photosensitive material and resin can be dissolved, ethyl cellosolve acetate 1. etc. can also be used. Of course, the solvent is not limited to these.

(Example 25) A contrast enhanced material for pattern formation (hereinafter abbreviated as OEM) having the following composition was prepared.

Photosensitive compound g Novolac resin 7 g Ethyl cellosolve acetate 1.30 g The OEM prepared in this way has a KtF of 248.4 nm with a thickness o of 12 μm when this is used as a pattern-forming organic thin film.
It was found that the difference in transmittance at 248.4 nm before and after exposure to excimer laser light was as large as 60q6 or more, and that it worked to improve the contrast of incident light.

A resist batten forming method using OEM according to the present invention will be shown with reference to FIG.

Substrate for semiconductors etc.”-1 with positive type) 5 (MP240
0 Nigyplay Co., Ltd.) to a thickness of 1.0 μm (Fig. 2a). Next, a water-soluble organic thin film 6, such as a mixed solution of glulan and polyvinylpyrrolidone, is spin coated on the positive resist 6 (FIG. 2C).

At this time, the mixing weight ratio of pullulan and polyvinylpyrrolidone was 4-1, and the film thickness was 0.1 to 0.3 μm so as not to affect pattern formation. Note that this intermediate organic thin film is provided to prevent the lower resist layer and the upper resist layer from mixing, and is not necessary. Next, the OEM of the present invention has a thickness of about 0.12 μm.
(Fig. 2C). Here, the lower resist layer, the intermediate organic thin film, and the intermediate organic thin film and CEM layer were laminated with excellent adhesion. Step 1: The CEM layer 7 was selectively exposed to 24B, 4 nm KrF excimer laser light 3 through the manufacturer 4 (FIG. 2d). Finally, the CEM layer 7 and the intermediate organic thin film 6 were simultaneously removed using an alkaline developer, and only the light irradiated portion 60 of the base resist 5 was developed and removed, thereby obtaining a resist pattern 5a (FIG. 2e). At this time, the resist pattern 6a was a line-and-subane pattern with a high aspect ratio of 0.3 μm.

(Example 26) An OEM consisting of the following composition was prepared.

An experiment similar to Example 25 was conducted using 7 g of novolac resin and 1-30 g of ethyl cellosolve acetate. The results were as good as in Example 25.

In the examples of the present invention, an alkali-soluble novolac resin is used as the resin, but an alkali-soluble phenol resin, a styrene resin, a copolymer resin of styrene and maleic acid, or a partial ester of maleic acid may also be used. , maleimide resin, etc. can also be used. Regarding the solvent, diethylene glycol dimethyl ether, which has a high transmittance in the deep ultraviolet rays, was used in this example, but there would be no problem even if ethyl cellosolve acetate or the like, which has high absorption in the far ultraviolet rays, was used.

Effects of the Invention The present invention provides a pattern forming material using a novel photosensitive compound having excellent reactivity to 248.4 nm KrF excimer laser.
When applied as a pattern forming material for F excimer lasers or a contrast enhancing material, fine patterns with a shape on the order of a submicron can be easily obtained, so it is of great value for forming ultra-fine patterns in the semiconductor industry.

[Brief explanation of drawings]

FIGS. 1 and 2 are cross-sectional views of a pattern forming method using the pattern forming material of the present invention, and FIG. 3 is an ultraviolet ray spectral curve diagram of the pattern forming material. 11. ...substrate, 2...--pattern forming material of the present invention, 3...excimer laser, 4...
・Mask, 6... Conventional pattern forming material, 6
...Water-soluble organic thin film, 8...Ideal resin pattern. Name of agent: Patent attorney Shigetaka Awano and one other person

Claims (14)

[Claims] (1) A pattern forming material comprising a photosensitive compound and a resin that generate sulfonic acid as a diazo group is eliminated by KrF excimer laser exposure in the presence of water, and a solvent capable of dissolving the compound and resin. (2) The pattern forming material according to claim 1, wherein the photosensitive compound has at least one ▲ mathematical formula, chemical formula, table, etc. ▼ bond. (3) Pattern formation according to claim 1 or 2, characterized in that the photosensitive compound has at least one ▲a mathematical formula, a chemical formula, a table, etc.▼bond. material. (4) Pattern formation according to claim 1 or 2, characterized in that the photosensitive compound has at least one ▲a mathematical formula, a chemical formula, a table, etc.▼bond. material. (5) Pattern formation according to claim 1 or 2, characterized in that the photosensitive compound has at least one ▲ mathematical formula, chemical formula, table, etc. ▼ bond. material. (6) Pattern formation according to claim 1 or 2, characterized in that the photosensitive compound has at least one ▲a mathematical formula, a chemical formula, a table, etc.▼bond. material. (7) The pattern forming material according to claim 1, 2, or 3, wherein the photosensitive compound has the following structure. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (R_1 and R_2 are substituents) (8) The pattern forming material according to claim 1, 2, or 3, wherein the photosensitive compound has the following structure. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (R_1 and R_2 are substituents) (9) The pattern forming material according to claim 1, wherein the photosensitive compound has at least one ▲a mathematical formula, a chemical formula, a table, etc.▼bond. (10) Claims described in any one of claims 1 to 9, characterized in that the photosensitive compound has at least one ▲ mathematical formula, chemical formula, table, etc. ▼ bond. patterning material. (11) At least one photosensitive compound ▲ has a mathematical formula, chemical formula, table, etc. ▼ has a bond as described in any one of claims 1 to 9 Pattern-forming material. (12) At least one photosensitive compound ▲ has a mathematical formula, chemical formula, table, etc. ▼ has a bond as described in any one of claims 1 to 9 Pattern-forming material. (13) At least one photosensitive compound in the molecule -S
The pattern forming material according to claims 1 to 13, characterized in that it has functional groups O_2Cl, -SO_3H, and -SO_2CH_3. (However, -SO_2
Cl includes its quaternary salts, and -SO_3H includes its ammonium salts, salts of organic bases, and quaternary salts. ) (14) At least one photosensitive compound in the molecule ▲ There is a mathematical formula, chemical formula, table, etc. ▼ or ▲ There is a mathematical formula, chemical formula, table, etc. ▼ or ▲ There is a mathematical formula, chemical formula, table, etc. ▼ A group that is Claims 1--
The pattern forming material according to item 14. (Here, X is -S
A functional group such as O_2Cl, -SO_3H, or -SO_2CH_3, and Y represents a substituent or functional group containing a hydrogen atom. (
However, -SO_2Cl includes its quaternary salt, and -SO_
3H includes its ammonium salts, salts of organic bases and quaternary salts. )