JPS595243A - Radiation sensitive composition and formation of pattern - Google Patents

Abstract

PURPOSE:To obtain the titled composition forming a film having resistance to oxygen plasma, by blending an org. iodine compound with a quinonediazido compound and a specified high molecular compound. CONSTITUTION:A radiation sensitive composition is obtd. by blending an org. iodine compound such as diiodomethane with a quinonediazido compound represented by formula I (where R is a substituent represented by formula II or III) and a high molecular compound compatible with said compounds, insoluble in water and soluble in alkali such as novolak resin in (0.1-3):(0.05-2):1 weight ratio. The composition is coated on a substrate and dried to form a film, and the film is irradiated through a prescribed pattern. The film is then heated to remove the iodine compound in the unirradiated part, and it is irradiated with plasma contg. oxygen to remove the unirradiated part.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radiation-sensitive composition and a pattern forming method using the same. More specifically, the present invention relates to a radiation-sensitive composition capable of forming a coating film resistant to oxygen plasma and a method for forming a knot using the same.

A radiation-sensitive composition comprising a quinonediazide compound, a novolak resin, etc. is used as an excellent positive photoresist in the production of lithographic printing plates, semiconductor devices, and the like. As an example of its usage, the composition is used as a coating film, a predetermined pattern is formed by a conventional method, and this pattern is used as an etching-resistant coating to etch the underlying substrate or thin film. The substrate or thin film to be processed is aluminum or silicon.

In the case of inorganic materials such as silicon oxide, processing has been carried out by using an appropriate chemical etching solution depending on the material, or by dry etching using chlorine or fluorine plasma. In general, dry etching is superior to wet etching using a chemical etching solution in terms of precision of the processed shape. On the other hand, if the substrate or thin film to be processed is an organic material, if a dry etching method is used, it is necessary to perform etching using plasma containing oxygen. As a result, a sufficient effect as an etching-resistant film cannot be obtained. In addition, making the film thick enough to withstand oxygen plasma makes it difficult to form a pattern accurately when exposing the photoresist coating to light, and in any case, it becomes difficult to form a pattern accurately. Cannot be etched.

An object of the present invention is to provide a radiation-sensitive composition capable of forming a strong coating film resistant to oxygen plasma, and a pattern forming method using the same.

General organic polymer compounds are decomposed into carbon dioxide, water, etc. by oxygen plasma, and then removed.

However, the present invention was completed based on the discovery that the presence of an iodine-containing organic compound in the coating film makes the coating film resistant to oxygen plasma.

The radiation-sensitive composition of the present invention comprises an organic iodine compound, a quinonediazide compound, and a water-insoluble, alkali-soluble polymer compound that is substantially compatible with these compounds.

The composition of the present invention contains an iodine compound, a quinonediazide compound, and a polymer compound in a weight ratio of 0.1 to 3 to 0.05.
Preferably in the range of ~2:1, 0.4~2:0
．． A range of 1 to 1:1 is more preferable.

The radiation-sensitive composition of the present invention can form both a negative pattern and a positive pattern.

That is, the composition is applied onto the substrate as usual.

It dries to form a coating film, is irradiated with radiation in a predetermined pattern, and is treated with a developer (e.g., tetramethylammonium hydroxide 2).
When developed with an alkaline developer (such as a water bath solution),
The exposed areas are dissolved and a good positive pattern is obtained.

On the other hand, if a compound that can be dispersed by heating is used as the iodine compound, a negative pattern can be formed by the following method. Forming a coating film in the same manner as above, irradiating the coating film with radiation having a desired pattern,
Next, the coating film is heated to scatter the iodine compound in the unirradiated areas, and then plasma containing oxygen is irradiated to remove the unirradiated areas.

Although it is not clear how the upper pyodine compound and the quinonediazide compound react or decompose when irradiated with the above radiation, at least the iodine-containing portion of the above compound is substantially fixed in the polymer compound layer. be done. The reason for this fixation is presumed to be that the quinonediazide compound or its reaction product or decomposition product binds to the iodine compound so that the iodine compound is not dissipated by heating. This explanation is merely an estimate, and whether or not this explanation is correct does not affect the structure of the present invention in any way.

In any case, iodine is present in the irradiated portion of the coating film.

It is thought that a substance that is nonvolatile and resistant to the oxygen-containing plasma is generated in the surface layer in the oxygen-containing plasma. On the other hand, the coating film in the unirradiated area where the iodine compound has been dissipated by heat is quickly removed by oxygen-containing plasma to form a negative coating film pattern. This phenomenon is not observed in compounds containing chlorine or bromine.

In order to carry out dry development in the present invention, it is necessary to dissipate the iodine compound by heating as described above. The heating temperature in this case needs to be higher than the temperature at which the iodine compound in the unirradiated area can be dispersed, that is, higher than the sublimation temperature or boiling point of the compound. Therefore, it depends on the iodine compound used, and it is possible to lower the heating temperature to some extent by placing the coating under reduced pressure. The upper limit of the heating temperature needs to be below the decomposition temperature of the polymer compound. Therefore, it is preferable to select a combination of an iodine compound and a polymer compound based on these points.

Additionally, some quinonediazide compounds decompose thermally before reaching their sublimation temperature or boiling point. Therefore, when using such a type of quinonediazide compound, it is preferable to select an iodine compound that is dissipated at a temperature lower than its decomposition temperature.

The polymer compound that is substantially compatible with the above-mentioned iodine compound and quinonediazide compound means that the mixture of the two compounds can form a coating film having a substantially uniform composition. Moreover, even if the polymer compound Ps is not compatible with a certain iodine compound or quinonediazide compound, the polymer compound P! which is compatible with the above Pl! If a mixture of the two, ie, Ps+P*, shows compatibility with both of the above compounds, such a polymeric compound can be used.

As these polymer compounds, those having further excellent coating properties are preferable.

Examples of the above alkaline aqueous solution-soluble polymer compounds include polyvinylphenol and novolak resin.

Styrene/maleic anhydride copolymers, polymers having carboxyl groups, such as cellulose acetate hydrodiene 7-thaleate, polyvinylhydroxybenzoate, polyvinylhydroxybenzal, polymethacrylic acid, and polyacrylic acid are used.

Examples of the quinonediazide compound include the general formula (wherein R represents a substituent represented by (11) CxHs (12)). In addition, quinonediazide compounds used in known photosensitive compositions can also be used.

Also, 2s! The above can also be used simultaneously.

The above iodine compounds include short methane, iodoform, iodoethane, 1-iodoethane, 1-io)'
Hebutane, 1-iodopropane, 2-iodopropane,
1.2-short ethane, 1°4-short butane, iodotrimethylsilane, 2-iodo-1,1,1-1-lifluoroethane, (iodomethyl)trimethylsilane,
Iodoacetamide, iodoacetic acid, 3-iodopropionic acid, 2-iodoethanol, 2-iodoaniline, 3
-Iodine 7=! 4-iodoaniline, 4-iodoaniline, 5-iodoanthranilic acid.

-iodobenzoic acid, m-iodobenzoic acid, p-io)”
repose! acid, p-iodobenzenesulfonyl chloride,
o-iodobenzyl alcohol, m-iodobenzyl alcohol, p-iodobenzyl alcohol, 0-iodobenzyl chloride, 1-iodo-2-nitrobenzene,
1-iodo-3-nitrobenzene, l-iodo-4-nitrobenzene, 2-iodophenol, 3-iodophenol, 4-iodophenol, 5-io)' t I
J f fluoric acid, 0-iodotoluene, m-iodotoluene, p-iodotoluene, 0-iodo-〇, Q, Q-trifluorotoluene, 2-iodo-6-methyl-3-pyridinol, 2-iodo- 3-Viridinol, 4-iodohyrazole, 2-iodothiophene, 3-iodothiophene, 2.6-diiodo-4-nitroaniline, 2.6
-diiodo-4-ditrophenol, 3,5-short-4-pyridone-N-acetic acid, 4-hydroxy-3,5
-short benzoic acid, 2.4.5-1 rhodobenzoic acid, 3,4.5-) rhodobenzoic acid, 2,4°6-triiodophenol, etc. are used.

In the present invention, the iodine compound and the polymer compound may be the same, such as iodinated polyvinylphenol. In this case, dry development is not possible and wet development must be used.

In the present invention, radiation refers to visible light and ultraviolet light.

X-rays refer to radiation in a broad sense, including radiation beams and ion beams. Further, plasma containing oxygen means that it may contain nitrogen or the like in addition to oxygen, but it is preferable to use oxygen plasma itself.

The fact that the coating film containing iodine described above is resistant to plasma containing oxygen will be explained with reference to FIG. First, as a quinonediazide compound, 2,3-dihydroxy-4-
(1,2-naphthoquinonediazide-5-sulfonyl)benzophenone, 25 parts by weight and m,p-cresol novolak resin (product of Gunei Chemical Industry Co., Ltd., P8F-280)
3), 100 parts by weight and 2-ethoxyethyl acetate, 300 parts by weight
A photosensitive composition solution consisting of heavy parts is prepared. This is applied onto a silicon substrate using a spinner and dried to prepare a sample. Next, a predetermined amount of 2.4.6-) rhodophenol as an iodine compound was added to this solution, and the content of the iodine compound in the solid component was 17% by weight, 33% by weight, and 50% by weight, respectively. I prepared a solution like this. Each of these was coated on a silicon substrate with a spinner and dried to prepare a sample. These samples were placed on the lower electrode of a plasma experimental apparatus containing a parallel plate plasma reaction vessel with a maximum output of 600 W and an electrode diameter of 60 pieces, and after exhausting the air, oxygen gas was introduced to bring the pressure inside the reaction vessel to zero.
．． After adjusting to 5 Torr, a high frequency of 13.56 MH2 was applied to generate oxygen plasma in the plasma reaction vessel with an output of 55 W, and the oxygen plasma was irradiated for a predetermined time. Oxygen plasma irradiation time was 50% by weight, 2 was 33% by weight, 3 was 17% by weight, and 4 was a sample containing no oxygen at all. From FIG. 1, it can be seen that as the content of iodine compounds increases, the oxygen plasma resistance increases. Therefore, coatings containing iodine compounds can serve as a mask against oxygen plasma.

The present invention will be explained below using examples.

Example 1, "+P-cresol novolak resin (PSF-2803, product of Gunei Chemical Industry Co., Ltd.), 100 parts by weight, 2.3
-dihydroxy-4-(1,2-naphthoquinonediazide-5-sulfonyl)benzophenone, 25 parts, 2,
4. Mix 62 & 5 parts by weight of 6-1 lyodophenol and 300 parts by weight of 2-ethoxyethyl acetate to prepare a sample solution.

A coating film of polyimide-based polymer compound PIQ (trade name, Hitachi Chemical Co., Ltd.) with a thickness of 0.8 μm is formed on a silicon substrate to form an organic material coating substrate.

The sample solution was applied using a spinner onto this organic material coating substrate, and then baked in air at 90C for 20 minutes to a thickness of 0.9
A photosensitive composition coating film with a thickness of μm was formed and used as an exposed sample. After irradiating this exposed sample with light from a SOOW high-pressure mercury lamp for 7 seconds through a test baton mask,
When developed using an aqueous solution of tetramethylammonium hydroxide, the line width and spacing were both 1μ with no swelling.
M's repeated positive type slams were made with good accuracy. This sample substrate was placed on the lower electrode of a plasma experimental apparatus having a parallel plate type plasma reaction vessel with a maximum output of 600 W and an electrode diameter of 60 m, and after exhausting the air, oxygen gas was introduced to reduce the pressure inside the reaction vessel to 0. Adjusted to 5Torr, 13.56MH
2, high frequency was applied to generate oxygen plasma in the plasma reaction vessel for 20 minutes at an output of 60 W. Once the inside of the reaction vessel was evacuated and returned to atmospheric pressure, the sample was taken out and examined under a microscope, and an organic coating film that faithfully reflected the test pattern was formed.

Example 2 A sample solution was prepared in the same manner as in Example 1 using a phenol novolac resin (ALNOVOL PN430, manufactured by West German Hoechst) as the novolac resin. Exposure was carried out in the same manner as in Example 1 using this sample solution.

An organic coating film could be formed by development and oxygen plasma irradiation.

Example 3 An organic material coated substrate was prepared by forming a polystyrene coating film with a thickness of 1 μm on a silicon substrate.

This was coated with the same sample solution as in Example 1 using a spinner and baked to form a photosensitive composition coating film with a thickness of 0.9 μm, which was used as an exposure sample. An organic coating film could be formed by , development, and oxygen plasma irradiation.

Example 4 Polyvinylphenol having a weight average molecular weight (My) of about 5800 was iodinated by the method of Chabpier et al. to obtain iodinated polyvinylphenol. A sample solution was prepared in the same manner as in Example 1 using this iodinated polyvinylphenol as an iodine compound. Using this sample solution, Example 1
Similarly, an organic coating film could be formed by exposure, development, and oxygen plasma irradiation.

Example 5 The same m, p-cresol novolac resin as in Example 1 is dissolved in 2-ethoxyethyl acetate to form a 7 weight percent solution. Furthermore, naphthoquinone-(1,2)-diazide sulfonic acid-(4)-methylphenyl (!:2,4.6-
Add 1 lyodophenol. Novolak resin and naphthoquinone-(1,2)-diazide sulfonic acid-(4)
The mixing ratio of -methylphenyl and 2.4.6-) IJ iodophenol was 1:0.2:0.5 by weight. This solution was applied onto a silicon wafer using a spinner to form a film with a thickness of □0.66 μm. Then X
After irradiating a predetermined pattern with light from an e-Hg lamp, the sample was post-baked at 120C for 20 minutes to obtain a plasma-developed sample. When dry development was performed in oxygen plasma under the same conditions as in Example 1, a fine negative pattern was obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the change in film thickness of a coating film due to oxygen plasma for explaining the present invention. Continuing from page 1 0 Author: Takahiro Kobashi, Hitachi, Ltd. Central Research Laboratory, 1-280 Higashi-Koigakubo, Kokubunji City 0 Author: Nonogaki Sanbe, Hitachi, Ltd. Central Research Laboratory, 1-280 Higashi-Koigakubo, Kokubunji City

Claims (1)

[Scope of Claims] 1. A radiation-sensitive composition comprising an organic iodine compound, a quinonediazide compound, and a water-insoluble, alkali-soluble polymer compound that is substantially compatible with these compounds. 2. The weight ratio of the organic iodine compound, quinonediazide compound and polymer compound is 0.1 to 3 to 0.05.
2. The radiation-sensitive composition of claim 1, wherein the amount ranges from 2 to 1. 3. The alkali-soluble polymer compound includes polyvinylphenol, Novo2Tsukuj4, SfV7/maleic anhydride copolymer, cellulose acetate hydrogen phthalate, polyvinylhydroxybenzoate, polyvinylhydroxybenzal, polymethacrylic acid, and The radiation-sensitive composition according to claim 1 or 2, which is at least one polymeric compound selected from the group consisting of polyacrylic acid. 4. The iodine compound may be short methane, iodoform, iodoethane, 1-iodobutane, 1-iodohebutane, 1-iodopropane, 2-iodofuropane, 1.
2-short ethane, 1,4-short butane, iodotrimethylsilane, 2-iodo-1,1,i-trifluoroethane, (iodomethyl)trimethylsilane, iodoacetamipi, iodoacetic acid, 3-iodopropionic acid, 2-iodoethanol, 2-meataniline, 3-iodoaniline, 4-iodoaniline, 4-iodoanisole, 5-iodoanthranilic acid, 0-iodobenzoic acid, m-iodobenzoic acid, p-iodobenzoic acid, p ”−
Dobenzenesulfonyl chloride, 0-iodobenzyl alcohol, m-iodobenzyl alcohol, p-iodobenzyl alcohol, 0-iodobenzyl chloride,
1-iodo-2-nitrobenzene, 1-iodo-3-nitrobenzene, 1-iodo-4-nitrobenzene, 2-
Iodophenol, 3-iodophenol, 4-iodophenol, 5-iodov lytic acid, O-iodotoluene, m-iodotoluene, p-iodotoluene, 0-iodo-Ql Ql α-trifluorotoluene, 2-iodo )'-6-mef-3-viridinol, 2-iodo-
3-Viridinol, 4-iodohyrazole, 2-iodothiophene, 3-iodothiophene, 2,6-diiodo-4-nitroaniline, 2,6-diiodo-4-ditrophenol, 3.5-short-4-pyridone -N-acetic acid, 4-hydroxy-3,5-short benzoic acid, 2
, 4.5-triiodobenzoic acid, 3,4.5-1 lyodobenzoic acid and 2,4.6-triiodophenol.Claim 1. , the radiation-sensitive composition according to item 2 or 3. 5. The radiation-sensitive composition according to claim 1, wherein the iodine compound is an iodinated alkali-soluble polymer compound. 6. The radiation-sensitive composition according to claim 1, wherein the polymer compound is an iodinated alkali-soluble polymer compound. 7. The radiation-sensitive composition according to claim 1, wherein the iodine compound and the polymer compound are the same substance and are iodinated water-insoluble and alkali-soluble polymer compounds. a step of forming a coating film of a radiation-sensitive composition made of alkali-soluble polymer compound; a step of irradiating the coating film with radiation having a desired pattern; heating the coating film and coating the unirradiated areas with the iodine compound; A pattern forming method comprising the steps of scattering the film from the film and irradiating the coating film with oxygen-containing plasma to remove unirradiated areas. 9. The weight ratio of the organic iodine compound, quinonediazide compound and polymer compound is 0.1 to 3 to 0.05 to
9. The pattern forming method according to claim 8, wherein the amount is in the range of 2:1. 10. The pattern forming method according to claim 8 or 9, wherein the heating temperature of the coating film is a temperature equal to or higher than the sublimation temperature or boiling point of the iodine compound. 11. Claim 8, wherein the radiation is ultraviolet rays.
10. The method for forming a knot turn according to any one of Items 1 to 10.