JPS58219547A - Positive type radiation-sensitive organic high polymer material - Google Patents

Abstract

PURPOSE:To obtain the titled high polymer material having high sensitivity to radiation and suitable for use in the formation of a fine pattern by using an aldehyde polymer obtd. by copolymerizing >=2 kinds of aliphatic aldehyde monomers. CONSTITUTION:A positive type radiation-sensitive org. high polymer material made of an aldehyde polymer is obtd. by anionic-polymerizing a mixture of >=2 kinds of aldehyde monomers at 0--100 deg.C in a hydrocarbon or ethyl ether solvent in the presence of a polymn. catalyst such as diethyl aluminum. The aldehyde monomers are selected from aliphatic aldehydes represented by a formula R-CHO (where R is alkyl, alkyl halide, aralkyl or aralkyl halide). When the aldehyde polymer is irradiated, the irradiated part is disintegrated and scattered by a chain reaction, so a pattern can be formed without especially carrying out a development stage.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an electron beam, an
#, relates to a positive radiation-sensitive organic diamolecular material that exhibits high sensitivity to radiation such as ion beams.

Conventionally, pattern forming methods for manufacturing electronic components such as semiconductor devices, magnetic bubble memory devices, and integrated circuits include:
A wide range of methods using photoresists sensitive to ultraviolet or visible light have been put into practical use.

In recent years, for the purpose of increasing the density and integration of semiconductor devices, there has been a demand for a method for forming patterns with a width of 1 pm or less.

However, in the method using the above-mentioned light, due to the inherent properties of the light such as diffraction, scattering and interference, 1) it is extremely difficult to form a pattern with a width of sm or less with high accuracy; The yield was also significantly reduced. Method a, which uses ultraviolet rays or visible light, was unsuitable as a method for forming patterns with a width of 12 m or less.

To address this, instead of the photolithography mentioned above,
Phosphorography techniques using high-energy radiation such as electron beams, X-rays, and ion beams have been developed and researched at the same time, and various materials that are sensitive to the radiation have been studied.

Among these, positive radiation-sensitive organic polymer materials that induce a scission reaction in polymer chains by irradiation with radiation, and the irradiated portion becomes soluble in a developer to form a pattern;
Tokuba, poly(methyl methacrylate), poly-(1-
Butenesulfone) etc. induce a cross-linking reaction by irradiation with radiation, and the irradiated part becomes insoluble in the developer, making it possible to create patterns with bird resolution compared to negative radiation-sensitive organic island molecular materials that form patterns. It is extremely convenient for use as a resist material for microfabrication.

However, the sensitivity of positive-tone radiation-sensitive organic polymer materials, including the materials mentioned above, is 1/1 that of negative-tone materials.
As a result, the time required for pattern formation is long, making it impractical in terms of productivity.

Furthermore, when considering the manufacture of semiconductor devices and the like, several resist steps are used.

Each V and JI process requires resist coating, drying, light or radiation irradiation, and development, and a typical wet development process takes several tens of minutes.

After the resist is developed, the time required to move the urethane to the next processing step is even more time consuming, and there is a strong desire in the semiconductor industry for a rapid development process and processing methods that use little wet solvents. Ta.

An object of the present invention is to provide a positive radiation-sensitive organic polymer material having high sensitivity to high-energy radiation such as electron beams, X-rays, and ion beams, which eliminates the drawbacks of the prior art as described above. In particular, a positive radiation-sensitive organic polymer material characterized in that when irradiated with radiation, the irradiated part disintegrates in a chain and scatters, so that a pattern can be formed without a special development process. Our goal is to provide the following.

In order to achieve the above object, the present inventor has investigated various organic polymer materials that are thought to have radiation sensitivity.
Two or more types of aliphatic aldehydes + lI as materials for this glue
We have discovered an aldehyde-based polymer in which l materials are co-stitched together.

In other words, aldehyde-based polymers with a polyether type structure as described above have extremely high sensitivity because the polymer chains are chain-disintegrated by irradiation with high-energy radiation such as electron beams, X-rays, and ion beams. A self-developing type that can be used as a positive resist material, and since the irradiated area is scattered at the same time as the radiation is irradiated, patterns can be formed without a special development process, which can significantly shorten the manufacturing process. It has the characteristic of being a positive resist material.

Next, materials used in the present invention will be explained.

In general, homopolymers of aliphatic aldehydes have high crystallinity and are poorly soluble in many organic solvents, so they cannot be used as resist materials.

The present inventor conducted extensive research to obtain a polymer that can be used as a resist material by improving the solubility of aldehyde polymers, and as a result, the radiation-sensitive organic polymer material of the present invention was obtained as follows. It came to this.

That is, as a result of research, 2ff1 of aliphatic aldehydes
It is known that aldehyde copolymers with improved solubility can be obtained by increasing the weight of the above di compounds by 7 ions (for example, Tanaka et al., Koka, Japanese Journal, 694 (196
3)) It has been found that it can be used as a radiation-sensitive organic polymeric material.

The aliphatic aldehyde monomer used in the present invention includes:
A mixture of two or more aldehyde monomers selected from aliphatic aldehydes of the general formula 1 (, -0HO, where R is an alkyl group, a halogenated alkyl group, an aralkyl group, or a halogenated aralkyl group). The above alkyl group 2 preferably has 1 to 8 carbon atoms.

If the fi&monowarikura is regulated by polymer composition, the composition range will be selected such that the maximum component contained in the copolymer does not exceed 99 moles.However, in order to obtain a copolymer with particularly high solubility, For this purpose, it is desirable that the largest component contained in the copolymer be less than 80 mol% fi.

Polymerization catalysts used when obtaining the polymer of the present invention by anionic polymerization include dimethylaluminum (diphenyl)amide (OH3)zAt-N(06H5)2, diethylaluminium(diphenyl)amide (02]H5)
2At-N (06Hs)2, ethylaluminum bis(diphenyl)amide (021-15)At-[N(O
eHs)2]2, ethylzinc(diphenyl)amide 02
Examples include, but are not limited to, H5ZnN(06,H5)2, ethylmagnesium(diphenyl)amide02)15MgN(OeHs)2, and the like.

The amount of catalyst is not limited, but aldehyde monomer 11
It is appropriate to add it at a ratio of 0.1 to 5 molti per one product.

In carrying out anionic polymerization, it is not necessary to use a polymerization medium, but if necessary, it is preferable to use a hydrocarbon-based solvent such as toluene or an ethyl ether-based solvent.

Further, polymerization can be carried out at a temperature in the range of 00C to -100C, but usually -50C to -808C.
A temperature of .

Furthermore, the atmosphere for polymerization is preferably one in which the air in the vessel is sufficiently replaced with an inert gas such as nitrogen.

In the present invention, the technical method of polymerization itself is not limited, and the method includes a method of preparing an aldehyde polymer on a catalyst dissolved in an inert organic solvent under reduced pressure distillation, a method of preparing the aldehyde itself or a solution thereof, There is no problem in adopting any method such as adding the catalyst itself or a solution thereof.

When the radiation-sensitive organic polymer material of the present invention is used to form a pattern of a semiconductor element, etc., it is dissolved in a general-purpose organic solvent such as toluene or xylene, and is usually It is applied onto an element substrate by spin coating or dip coating.

After coating, when the desired pattern is irradiated with radiation after pre-baking under appropriate temperature conditions, the irradiated area collapses and scatters, causing the positive resist pattern to disappear during the development process. You can get it without.

Note that the necessary area stitching may be performed by wet development using a toluene □ isopropyl alcohol organic solvent.

As mentioned above, the radiation-sensitive organic polymeric material of the present invention, which is an aldehyde-based polymer, can be used alone for development processing by radiation irradiation. :' A resist pattern can be formed without any trouble, but if necessary, it may be used in combination with novolac resin, polyacrylic acid ester polymer, polyisoprene resin, polystyrene, etc.

At this time, a developer is selected depending on the polymer that has been produced.
For example, it is possible to produce resins with various properties such as dry etching resistance.

In addition, although the 11 aldehydes of the present invention exhibit high sensitivity to radiation, they are also sensitive to light.
, it can also be used as a photosensitive material.

The present invention will be specifically explained below with reference to synthesis examples and examples.

Synthesis Example 1 Diethylaluminium diphenylamide, (02H5)
Synthesis of zAt-N(Osll)2 was performed as follows.

That is, after the inside of a 200-470 flask equipped with a stirrer, dropping funnel, three-way cock, and thermometer was sufficiently purged with nitrogen, toluene 33- and (OH30H
2) Introduce 3 At14.5 f (0,127 moA) using a syringe through a three-way stopcock under a nitrogen stream. Stir for a while to make a homogeneous solution, then add 21.4 f (0,127 moA) of diphenylamine under water cooling. 127m o L)
A solution of 40% of toluene is gradually added dropwise.

After the dropwise addition was completed, the temperature of the reactant was raised to 6,000 ℃, and the reaction was completed by stirring gently for 2 hours.

The produced (02H5)2AI-N(OsHs)2 was stored in a toluene solution container with a three-way cock under a nitrogen stream.

Synthesis examples 2-181 Polymerization was carried out using a double tube with a three-way stopcock.

Specifically, a predetermined amount of aldehyde monomer and a solvent (usually toluene was used) are introduced into a cylindrical polymerization vessel having a capacity of about 100 cm under a nitrogen stream using a syringe through a three-way stopcock.

The above-mentioned container containing the monomer solution is cooled to 0.000 °C in an ice-water bath, and a predetermined amount of the catalyst solution obtained in Synthesis Example 1 is gradually dropped therein while vigorously moving the container.

After adding the catalyst, the container is cooled to -78°0 in a dry ice □ acetone bath, and left to stand for a predetermined period of time. After polymerization, the heavy mixture is treated with ammoniacal methanol to remove the lungs and medium. After decomposition, it was immersed in methanol for one day, filtered, washed several times with methanol, and dried in vacuum.

Depending on the situation, the monomer solution was added to the catalyst solution for polymerization.The composition ratio of the copolymer was determined by elemental analysis or thermal analysis of the gas produced.

(Rust'rA4fJ) Table 1 Polymerization time = 24 hours, total monomer amount: 10n mmo
Ls solvent: toluene, total amount of reaction mixture: 27 mZ
, initiator (CtHs)*AIN (C6HI)! :
Abbreviation of OA8mmot monomer AA: Acetaldehyde BA Nibutyraldehyde PA Nibrobanal PhPA: 5-phenylpropanal HA: Heptanal IBA: Isobutyraldehyde Example 1 The copolymer of acetaldehyde and butyraldehyde obtained in Synthesis Example 2 was dissolved in xylene. , a resist solution of 0.2 weight was prepared. Next, the above resist solution was applied onto a silicon wafer and prebaked for 8000.20 minutes to form a polymer film with a thickness of t5Jjm. Place it in the irradiation device and apply an acceleration voltage of 20kv in vacuum.
As a result, the irradiated area was coated with a layer of heat treatment, and the areas irradiated with different doses were Measure the thickness of the remaining polymer film using a thin film step meter,
The residual film thickness (normalized) was plotted against the electron beam irradiation t (coulombs/-), and FIG. 1 showing the electron beam sensitive characteristics was obtained.

The minimum irradiation dose at which the residual film rate becomes zero was calculated, and was found to be 8.
X10 coulombs/-, and it was confirmed that it was an extremely sensitive positive resist.

9, the electron beam sensitivity of methyl polymethactulate, a typical positive resist, is lX10' coulombs/cYI.
It was confirmed that the positive resist material of the present invention exhibits a sensitivity that is two orders of magnitude higher than that of polymethyl methacrylate.

Example 2 1 ml of acetaldehyde and butyraldehyde obtained in Synthesis Example 2 was dissolved in toluene to prepare a 0.3% by weight resist solution.

Subsequently, the above resist solution was applied onto a silicon wafer, prebaked at 3000 ml for 20 minutes, and 2.0 pm
A thick polymer film was formed.

This was placed in a soft X-ray generator and irradiated with soft X-rays with a wavelength of 4.2 A' generated from a 10 kW rotating water-cooled silver target in a vacuum, and the residual film thickness (normalized) and soft X-ray irradiation amount were determined. (m
The relationship between T/ and 11) was determined.

The results are shown in FIG. 2. The minimum irradiation dose at which the film thickness becomes zero was determined to be 19 m/-, and it was confirmed that the resist was an extremely sensitive positive resist.

Tohebo, the soft X-ray sensitivity of polymethyl methacrylate, a typical positive resist, is approximately 2000 mJ/-.
It was confirmed that the positive resist material of the present invention has soft X-ray sensitivity two orders of magnitude higher than that of polymethyl methacrylate.Examples 3 to 61 Synthesis Examples 3 to 8) Aldehydes obtained in Synthesis Examples 3 to 8) The copolymer was dissolved in xylene to prepare a resist solution of about 0.2% by weight.

Subsequently, the above resist solution was applied onto a silicon wafer and prebaked for 20 minutes at %80'0 for about 1.5 p.
A polymer film with a thickness of m was formed.

Sensitivity or soft Xtj! The sensitivity was determined and the results are summarized in Table 2, and it was confirmed that all of them had high sensitivity to radiation and were highly sensitive positive resists.

Comparative Examples As in the Examples, the numbers in 0 are the moles in the copolymer for acetaldehyde homopolymer or butyraldehyde homopolymer. represents the ratio.

Monomer abbreviations AA: acetaldehyde BA nibutyraldehyde PA nibrobanal PhPA: 3-phenylprobanal HA: heptanal IBA: isobutyraldehyde We tried to evaluate it as a resist material, but none of them could be dissolved in general-purpose organic solvents. However, nothing that could be put to practical use could be obtained.

As is clear from the above description, according to the present invention, it is highly sensitive to radiation such as electron beam,
It is possible to manufacture structures, and has a remarkable effect on the manufacture of semiconductor devices, etc.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the electrosensitivity a characteristics of the radiation-sensitive polymer material of the present invention, and FIG. 2 is a diagram showing the sensitivity and buffing properties of the radiation-sensitive polymer material of the present invention. 1 figure

Claims (1)

[Claims] 1. A positive radiation-sensitive organic polymer material comprising an aldehyde polymer. 2. The aldehyde polymer is an aliphatic aldehyde monomer represented by the general formula R-OHO (wherein R represents an alkyl group, a halogenated alkyl group, an aralkyl group, or a halogenated aralkyl group). The polymer according to claim 1, characterized in that it is made of a mixture of two or more selected aldehyde monomers copolymerized with each other.
Di-type radiation-sensitive organic polymer material 0