JPS636545A - Self-developing positive type electron beam resist and pattern forming method using the same - Google Patents

Abstract

PURPOSE:To obtain the titled resist having a high sensitivity and being a self- developing type by forming the positive type electron beam resist obtd. by depositing a metallophthalocyanine derivative on a substrate, thereby easily forming a resist film to a single composition. CONSTITUTION:The titled resist is composed of the metallophthalocyanine derivative shown by the formula wherein M is a metal atom, L is a ligand, Pc is a phthalocyanine ring (n) is an integer of 1 or 2. Said derivative is for example, sodium dicyanocobaltphthalocyanine, etc. The resist is obtd. by dissolving the metallophthalocyanine derivative to a solvent to form an electrolyte, and by depositing a crystal of the electrolysis product on an electrode by effecting the electrolysis of the electrolyte, followed by depositing the obtd. crystal on a substrate such as a glass, etc. The pattern is formed by irradiating the electron beam on the resist film, followed by removing the exposed part of the resist film. Thus, as the resist is produced from the metallophthalocyanine derivative, the titled resist having a high sensitivity and enabling a dry process is obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a resist for electron beam lithography, specifically, a so-called self-developing type resist that can be patterned only by electron beam irradiation and does not require development. The present invention relates to a positive resist that can be patterned by a dry process and a pattern forming method using the resist.

[Conventional technology]

Photoresists that are sensitive to ultraviolet rays have been mainly used as resist forming materials for forming circuit boards and the like using photolithography.

However, ultraviolet resists have limited resolution mainly due to the diffraction and interference effects of the ultraviolet rays themselves.
It is no longer sufficient to support the formation of finer resist patterns required for manufacturing more highly integrated circuits such as .

Therefore, new exposure techniques and resist forming materials that can form finer resist patterns are being actively developed.

Among these, exposure technology using electron beams has excellent properties for forming fine patterns in principle with almost no influence of diffraction or interference, and the development of peripheral equipment such as light sources and masks is remarkable.
For example, it is attracting attention as a technology that can form finer resist patterns of 1- or less with high resolution.

Polymethyl methacrylate (PMMA) is known as a typical positive electron beam resist. Compared to negative resists such as polyglycidyl methacrylate, this positive electron beam resist has the advantage of superior resolution and ease of handling without post-polymerization effects, but its disadvantage is low sensitivity. . Therefore, in order to increase the sensitivity, onium salt compounds such as tetramethyltin and Ph5SAsF6-, which have the effect of promoting scission of the main chain of the resin in response to electron beams, are often added to the resin.

[Problem that the invention seeks to solve]

However, with positive electron beam resists formed by adding various additives to resins such as PMMA that have the effect of reacting with electron beams and promoting scission of the main chain of the resin, for example, it is difficult to achieve uniform sensitivity throughout the resist. In order to obtain resolution, a plurality of components must be mixed uniformly, and the amount of each component is also delicate, requiring special techniques for this purpose.

- On the other hand, in patterning, conventional resists require a step of removing unnecessary portions by development treatment after exposure. Therefore, attempts have been made to use so-called self-developing resists that can omit this development process, that is, resists that can remove unnecessary portions at the same time as pattern exposure, using PMMA, etc., but all of these resists require a large amount of electron beam irradiation. The current situation is that there is no one that is satisfactory in terms of sensitivity.

An object of the present invention is to provide a positive electron beam resist film that has a single composition, is easy to form, and has excellent sensitivity.

Another object of the present invention is to provide a self-developing type resist that does not require development treatment after pattern exposure unlike conventional resists,
Moreover, it is an object of the present invention to provide a highly sensitive positive electron beam resist film.

Another object of the present invention is to provide a method for forming a fine resist pattern which can be carried out by a dry process and which simplifies the manufacturing process by omitting the conventional development process.

Another object of the present invention is to provide a functional film made of a patterned metal phthalocyanine derivative film and a method for forming the same.

[Means for solving problems]

The objects described above can be achieved by the present invention as described below.

That is, the present invention provides a self-developing positive electron beam resist characterized by comprising a metal phthalocyanine derivative;
and irradiating a metal phthalocyanine derivative film formed on a substrate with an electron beam, removing the irradiated portion from the substrate, and forming a pattern on the substrate consisting of the non-irradiated portion of the film. This is a characteristic pattern forming method.

The metal phthalocyanine derivative for forming the electron beam resist of the present invention includes, for example, a compound represented by the following general formula (I).

MPc (L)n ---CI) (In the above formula, M is a metal atom, L is a ligand, Pc is a phthalocyanine ring, and n represents 1 or 2.

Preferred as M (metal atom) in the above general formula (I) are trivalent or higher valent metals, such as aluminum, indium, gallium, tin, lead, titanium, germanium, silicon, thorium, antimony, vanadium,
Examples include chromium, molybdenum, uranium, manganese, iron, cobalt, nickel, hafnium, rhodium, palladium, osmium, and platinum. Among these, transition metals belonging to Group 1 of the periodic table are particularly preferred.

Preferred as L (ligand) in the above general formula (I) are groups made of nitrogen-containing organic compounds, such as cyano group, piperidino group, piperidyl group, l-methylimidazolyl group, pyridyl group, 2- Methyl pyrazinyl group, 3
, 4-dimethylpyridyl group, 3.5-dimethylpyridyl group, 4-methylpyridyl group, 3-chloropyridyl group, pyrazinyl group, 3-ethylpyridyl group, 4-ethylpyridyl group, 3-acetylpyridyl group, 4-acetyl group Pyridyl group, bipyridyl group, dicyanobenzyl group, cyanobenzyl group, and further aliphatic amide groups such as dimethylamino group, ethylamino group, propylamine group, butylamino group,
Anilino group, methylanilino group, dimethylanilino group,
Examples include aromatic amine groups such as naphthylamino groups, and halogen atoms such as chlorine and bromine. When n is 2, these ligands may be the same or different.

Such a metal phthalocyanine derivative can be obtained by a known method. For example, after obtaining a metal phthalocyanine by the method described in "Phthalocyanine Compounds" by Moser and Thomas, the above-mentioned ligand is simply added to the metal phthalocyanine. A metal phthalocyanine compound is produced by reacting a metal with phthalic acid or a phthalic acid derivative such as phthalimide, phthalonitrile, or aminoiminoindolenine in the presence of a nitrogen source and a catalyst as necessary. When synthesizing, a polyhalogenated metal is used as the metal, a metal phthalocyanine in which the metal has 1 to 2 /\ halogens is prepared, and the above-mentioned ligand is introduced using this halogen, or Examples include a method in which a metal phthalocyanine is synthesized and a polyhalogenated metal is introduced therein in the same manner as described above, but the method is not limited to these methods.

Note that the benzene nucleus of these metal phthalocyanine derivatives can have 1 to 16 substituents such as a halogen atom, a methyl group, a nitro group, a carboxyl group, and other substituents.

The electron beam resist of the present invention is made of the metal phthalocyanine derivative as described above, and is laminated on a predetermined substrate by various methods such as spin code method, Langmuir-Prodgett method, vapor deposition method, MBE method, and ion cluster beam method. Among them, vapor deposition method, MBE
Methods such as the method described above are preferred because they can form a high-quality electron beam resist film with good film-forming properties that are suitable for forming fine patterns and have uniform characteristics such as sensitivity over the entire film.

Such a vapor deposited film can be obtained by a normal vapor deposition method using the metal phthalocyanine derivative as described above.

Various metal phthalocyanine derivatives can be used in this vapor deposition method, but the following patent application
-274838, is a highly pure metal phthalocyanine derivative suitable for forming a deposited film with excellent properties as an electron beam resist, such as high sensitivity, using inexpensive equipment. It is particularly preferred because it can be obtained with easy operations.

That is, the metal phthalocyanine derivative described above exhibits acidity (or basicity) as a whole molecule, and has a base (
It tends to form salts with various organic solvents, preferably dipolar organic solvents, or mixed solutions of these and water, compared to conventional metal phthalocyanines. It is possible to crystallize it.

Crystallization can be easily achieved by inserting a pair of electrodes into a solution prepared by dissolving the desired metal phthalocyanine derivative in an appropriate solvent, and depositing crystals of the metal phthalocyanine derivative on the electrodes by performing direct current electrolysis. can be done.

Solvents for metal phthalocyanine derivatives used in this crystallization include acetonitrile, acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl isobutyl ketone, diethyl ketone, methyl formate, methyl formate, propyl formate, methyl acetate, ethyl acetate, butyl acetate. , cyclohexane, tetrahydrofuran, dioxane, methanol.

Ethanol, isopropyl alcohol, butanol, methyl cellosolve, butyl cellosolve, cellosolve acetate, formamide, dimethyl formamide, dimethyl sulfoxide, hexamethyl phosphotriamide or mixtures thereof with water, or mixtures thereof with water, or pentane,
Hexane, cyclohexane, heptane, octane, mineral spirits, petroleum ether, gasoline, benzene,
Toluene, xylene, chloroform, tetracarboxylic carbon! , mixtures with chlorobenzene, perchloroethylene, trichloroethylene, etc.

A pair of electrodes is inserted into a solution prepared by dissolving a desired metal phthalocyanine derivative in a solvent appropriately selected from these at a concentration of, for example, about 10' to about 10-IM, and a DC voltage or current is applied between these electrodes. By applying this voltage and performing electrolysis, crystals of the metal phthalocyanine derivative can be obtained on the electrode.

In addition, the solution for electrolysis may further contain KCI,
NaBr, K1. LiCl0. s, LiB
Electrolytes such as Fa, tetra-n-butylammonium verchlorate, tetra-n-butylammonium perfluoroporate, tetramethylammonium chloride, sodium p-toluenesulfonate, Na2SO, etc., for example, from about 10-3 to about 10-' You may add about M.

Electrodes used for electrolysis include metals such as gold, platinum, nickel, and copper, or those made by vapor-depositing these metals on insulating substrates such as plastic and glass, and tin oxide, indium oxide, and tin oxide. Any known electrode material such as an insulating substrate coated with a layer of conductive metal oxide such as indium can be used. The conditions for electrolysis vary depending on the type of metal phthalocyanine derivative used, the material, shape and size of the electrode, the type and concentration of the electrolytic solution and electrolyte, etc., but include constant potential of about 0.7 to 20 V, Alternatively, it is suitable to use a constant current of about 5 gA or more to obtain crystals for basic use.

Incidentally, when the metal phthalocyanine derivative is acidic, crystals are deposited on the surface of the anode, and when it is basic, crystals are deposited on the cathode.

By vapor deposition using the crystal thus obtained, a vapor-deposited film of a metal phthalocyanine derivative can be formed on a suitable substrate to a predetermined thickness to form a resist film for patterning.

The operating conditions during this base aging vary depending on the metal phthalocyanine derivative used, the type of substrate, etc., but include, for example, the degree of vacuum, to-1-to°' aa+Hg, crystal heating temperature; 400 to 450°C; substrate temperature; -10~20'C
This can be done under the following conditions.

The metal phthalocyanine derivative vapor-deposited film is used as a substrate on which the metal phthalocyanine derivative is laminated.

For example, it is selected as appropriate depending on whether it is used as a resist film for patterning other materials or as a patterned functional film itself. Examples include those made of semiconductors.

When the film made of the metal phthalocyanine derivative mentioned above is irradiated with an electron beam, when the amount of electron beam irradiation is low, discoloration occurs, which is presumed to be the result of a crosslinking reaction between each molecule.
When the irradiation dose of the electron beam increases, the electron beam becomes a heating source and sublimation of the metal phthalocyanine derivative begins to occur in parallel with the crosslinking reaction, and when the irradiation dose increases further, the ligand of the metal phthalocyanine derivative changes. It has the property of being able to remove the irradiated area from the substrate by decomposing it and sublimating it, that is, it has the property of being a self-developing positive resist that can perform patterning and development at the same time. ing.

Therefore, when patterning the metal phthalocyanine derivative film, it is necessary to perform pattern exposure with an amount of electron beam irradiation necessary to decompose and sublimate the derivative. patterning can be performed. The amount of electron beam irradiation required for patterning varies depending on the type of metal phthalocyanine derivative used, but is at most 10-θ~lO''IA
The resist of the present invention has extremely high sensitivity. Moreover, the resist of the present invention is composed of a single composition of metal phthalocyanine derivatives, resulting in a high-quality resist film with no variation in characteristics such as sensitivity over the entire resist film.

Formation of a pattern using the electron beam resist of the present invention can be carried out, for example, as follows.

First, a metal phthalocyanine derivative film is formed on a predetermined substrate using the various methods described above. The film thickness at this time is determined as appropriate depending on the use of the metal phthalocyanine derivative film after patterning, that is, whether it is used as a resist for patterning other materials or as a patterned functional film itself. be done.

Next, the metal phthalocyanine derivative film on the substrate is irradiated with an electron beam at the above-mentioned irradiation dose so that the non-irradiated areas form a desired pattern. Then, the electron beam irradiated portion of the film is removed from the substrate, leaving a desired patterned metal phthalocyanine derivative film on the substrate.

Note that if the metal phthalocyanine derivative film itself is used as a patterned functional film, it can be used as is, and if it is used for patterning other electrode materials, it can be used in the same way as conventional photoresists, etc. .

Examples of functional films that are patterned themselves include those that utilize the properties of the metal phthalocyanine derivative as a resistance heating element, resistor, electrode, sensor, etc., depending on the type of metal phthalocyanine derivative used.

〔Effect of the invention〕

The resist made of the metal phthalocyanine derivative of the present invention has a single composition that does not require additives to increase sensitivity unlike conventional resists, can easily form a homogeneous film, and is sensitive to electron beams. It has excellent properties and is suitable for use in electron beam lithography.

Further, since the electron beam resist of the present invention can be processed by a dry process and does not require development treatment unlike conventional resists, its use can greatly simplify the patterning process.

Further, according to the method of the present invention, a finely patterned metal phthalocyanine derivative film can be easily formed with good film formation properties, and the use of phthalocyanine compounds as functional films can be greatly expanded.

〔Example〕

Example 1 Sodium dicyanocobalt phthalocyanine was dissolved in dimethylformamide to a concentration of 2 x 10-2M to prepare an electrolytic solution. A pair of platinum electrodes are inserted into this electrolyte, the - side is connected to the anode of a DC power supply, and the other is connected to the cathode.
Electrolysis was carried out for 30 minutes at a constant voltage (1.5 V) to obtain crystals on the anode surface.
] =62.0. Hl = 3.0, N [%] =
21.4) Using the crystal thus obtained, vacuum degree: 10-2
mmHg, crystal heating temperature, 400℃, substrate temperature; O
The electrolytic product was deposited on a substrate made of glass that had been thoroughly cleaned by ultrasonic cleaning using detergent, water, and acetone in this order under the conditions of ``C'' and dried.
) was formed (elemental analysis value, C1=87.1.H
[$1 = 2.2, N ($1 = 20.0. Ash content 9
．． 5%) Next, an exposure mask capable of forming a linear pattern of each edge width is applied to the leather film of the electrolytic product on the substrate so that the irradiation amount with the vaporized M film is 2 X IOA A. A pattern was exposed to an electron beam.

Then, the radicals in the portions irradiated with the electron beam were removed from the substrate, forming a pattern with a line width of 1-.

Example 2 Dicyanoco/heltophthalocyanine potassium was made into a feed solution in acetonitrile and used as an electrolyte.

A pair of platinum electrodes were inserted into this electrolyte, the - side was connected to the anode of a DC power supply, and the other was connected to the cathode, and electrolysis was performed at a constant voltage (3V) for 1 hour. crystals were precipitated (10uX 70JLII X 20μ
s).

Using the crystal thus obtained, the vacuum degree was 10″To
rr, a vapor deposition film (1 scale) of the electrolytic product was formed on a silicon substrate washed with an HF aqueous solution under conditions of a crystal heating temperature of 380° C. and a substrate temperature of −10° C.

Next, an electron beam is applied to the vapor deposited film of the electrolytic product on the substrate through an exposure mask that can form linear patterns of various line widths so that the irradiation amount on the vapor deposited film is 4 Then, the deposited film on the part irradiated with the electron beam was removed from the substrate, and a pattern with a line width l- was formed.

Claims (1)

[Scope of Claims] 1) A self-developing positive electron beam resist comprising a metal phthalocyanine derivative. 2) A self-developing positive electron beam resist according to claim 1, comprising a vapor-deposited film of a metal phthalocyanine derivative. 3) The self-developing positive electron beam resist according to claim 2, wherein the vapor-deposited film of the metal phthalocyanine derivative is a vapor-deposited film of an electrolysis product of the metal phthalocyanine derivative. 4) A step of irradiating a metal phthalocyanine derivative film formed on a substrate with an electron beam, removing the irradiated portion from the substrate, and forming a pattern consisting of the non-irradiated portion of the film on the substrate. A method for forming a pattern characterized by: 5) The method for forming a pattern according to claim 4, wherein the metal phthalocyanine derivative film is a vapor-deposited film of the derivative. 6) The pattern forming method according to claim 5, wherein the vapor-deposited film of the metal phthalocyanine derivative is a vapor-deposited film of an electrolysis product of the metal phthalocyanine derivative.