JPS61232453A - Improved positive type photoresist developing solution - Google Patents

Abstract

PURPOSE:To prevent residues of a thin film and scum at the exposed areas after development by incorporating an alkali contg. no metal ion, a quaternary ammonium salt type cationic surfactant, and a monovalent alcohol in a developing soln. CONSTITUTION:The developing soln. capable of enhancing the solubility of a resist film at the exposed areas and preventing the residues of the thin resist film and the scum contains the alkali contg. no metal ion., such as amines, heterocyclic bases, or quaternary ammonium bases; the quaternary ammonium type cationic surfactant for enhancing selective solubility between the exposed and nonexposed areas, optimally, such as trimethyl-coconut oil derived alkyl- ammonium chloride; and as the third component to be added to a combination of said two, a kind of alcohol, embodied by methanol or ethanol.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a developer for positive photoresists. More specifically, the present invention relates to a developer for positive photoresists which is particularly suitable for image formation using quinonediazide-based positive photoresists and which does not leave a thin film or scum residue after development.

BACKGROUND ART Conventionally, when manufacturing semiconductor integrated circuit elements, integrated circuit manufacturing masks, printed wiring boards, printing plates, etc., selective processing such as etching and diffusion is performed on the base substrate. At this time, in order to selectively protect the unprocessed portions of the underlying substrate, a film is formed using a so-called photoresist, a composition sensitive to actinic rays such as ultraviolet rays and XLA% electron beams, and then imagewise exposed and developed. A method has been adopted in which a resist pattern is formed on a base substrate.

There are two types of photoresists: positive type and negative type. The former type has exposed areas dissolved in a developer but the non-exposed areas do not, and the latter type has the opposite type. A typical example of the former positive type photoresist is a combination of an alkali-soluble novolak resin as a paste and a naphthoquinone diazide compound as a photodegrading agent. An alkaline aqueous solution is used as a developer for this quinonediazide-based positive photoresist, but when manufacturing semiconductor devices, using an alkaline aqueous solution containing metal ions as a developer has a negative impact on the quality of the product. Therefore, developers that do not contain metal ions, such as tetramethylammonium hydroxide (IBM® Technical
Aqueous solutions such as yatrimethel (2-hydroxyethyl) ammonium hydroxide (US Pat. No. 4,239,661) are used.

By the way, in a positive photoresist developer, it completely dissolves the exposed areas and hardly dissolves the non-exposed areas.
Furthermore, it is important that the film has properties such as not causing any change in film thickness before and after development.

However, in conventionally used developers,
Dissolution selectivity for exposed and unexposed areas.

The so-called developer selectivity is not sufficient, and as a result, the resist film thickness of the resist pattern obtained after development is greatly reduced, resulting in poor dimensional accuracy, and the cross-sectional shape of the resist film after development becomes a trapezoid with tails. This also causes a decrease in resolution. As a result, in subsequent processes, such as dry etching.

It becomes difficult to control the processing dimensions of the underlying substrate. In particular, when a photoresist film is formed on a base substrate with steps, the film thickness is not the same between the convex and concave portions of one step, resulting in thicker and thinner portions, and these are all developed under the same exposure and development conditions. As a result, the difference in film thickness after development becomes even larger and the dimensional accuracy of the pattern becomes poor. In order to solve this problem, for example, an alkali that does not contain metal ions such as tetraalkylammonium hydroxide is used. , methylbis(2-hydroxyethyl)
A developing solution containing a quaternary ammonium type surfactant that does not contain metal ions such as coccyammonium chloride and trimethylcoccyammonium chloride (JP-A-58-
9143), and a cationic substance selected from tetraalkylammonium or haphosphonium, benzyltrialkylammonium or phosphonium, and benzyltriarylammonium or phosphonium, using tetramethylammonium hydroxide as a solute;
For example, a developer containing tetrapentylammonium (Japanese Unexamined Patent Publication No. 58-150949) has been proposed. However, although these developers have good dissolution selectivity for exposed and non-exposed areas, they have the disadvantage that they tend to leave a thin film or scum residue on exposed areas after development.

Problems to be Solved by the Invention The purpose of the present invention is to solve such problems and to provide a positive photoresist that does not leave a thin film or scum after development, and is particularly suitable for image formation using a quinonediazide-based positive photoresist. Means for solving the problem of providing a developer The inventors of the present invention have conducted extensive research and found that an alkali containing no metal ions improves the dissolution selectivity for exposed and non-exposed areas. By adding a certain type of alcohol as a third component to a combination of quaternary ammonium salt type cationic surfactants for the purpose of Based on this knowledge, the present invention was completed.The present invention is based on (A) an alkali containing no metal ions, (B) a quaternary ammonium salt type cationic The present invention provides a positive photoresist developer containing a surfactant and (C) a monohydric alcohol.

In the present invention, the metal ion-free alkali used as component (4) includes, for example, amines, heterocyclic bases,
Examples include quaternary ammonium bases.

As the amines, aromatic and aliphatic amines including primary, secondary and tertiary amines having linear, branched or cyclic substituents can be used, and suitable amines include Examples include alkylene diamides such as 1,3-diaminopropane, arylamines such as 4,4'-diaminodiphenylamine, and imines such as bis-(dialkylamino)imine. The alkyl group or alkylene group in these amines has a carbon atom number of 1-
12, and the aryl group is preferably a phenyl group or a phenalkyl group. Examples of the heterocyclic base include those having 3 to 5 carbon atoms and 1 or 2 heteroatoms selected from nitrogen, oxygen and sulfur in the ring skeleton, such as pyrrole, pyrrolidine,
Pyrrolidone, pyridine, morpholine, pyraziy% piperidine, oxazole, thiazole, etc. can be used.

As the quaternary ammonium base, for example, lower alkyl quaternary ammonium hydroxide is preferred. Particularly preferred among these metal ion-free alkalis are tetramethylammonium hydroxide and trimethyl(2-hydroxyethyl)ammonium hydroxide (choline). Furthermore, the alkalis that do not contain metal ions may be used alone or in combination of two or more.

There is no particular restriction on the type of quaternary ammonium salt type cationic surfactant used as component (B) in the present invention, and known aliphatic, aromatic, and heterocyclic quaternary ammonium salt type cations can be used. Any surfactant can be selected from among the surfactants. As such, for example, the number of carbon atoms is 2 to
Alkyltrimethylammonium salt with 20 alkyl groups, dialkyldimethylammonium salt, alkyldimethylethylammonium salt, alkylmethyldi(hydroxyethyl)ammonium salt, alkyldimethylbenzylammonium salt, alkylamidopropyldimethylbenzylammonium salt, alkyl group-substituted phenoxy Examples include ethoxyethyldimethylbenzylammonium salts, alkylpyridinium salts, alkylquinolinium salts, alkylisoquinolinium salts, alkylimidazolinium salts, and trialkylmethylammonium salts. Such higher alkyl groups may be singly or in combination, and may have unsaturated bonds, atoms such as sulfur, oxygen, nitrogen, benzene rings, naphthalene rings, etc. Good too.

These quaternary ammonium salt type cationic surfactants may be used alone or in combination of two or more.

This quaternary ammonium salt type cationic surfactant is
It is used to improve the dissolution selectivity between the exposed area and the unexposed area, and from the viewpoint of this effect, trimethylcodium cyanmonium chloride, methylbis(2- and droxyethyl)codium cyanmonium chloride, which has an alkyl group derived from coconut oil. and one example of trialkylmethylammonium salt: evatributylmethylammonium chloride,
Triamylmethylammonium chloride and triamylmethylammonium chloride are most suitable.

Next, m alcohols used as component (C) in the present invention are used to prevent thin film and scum remaining after development, and are preferably those having 1 carbon atom.
At least one alcohol selected from m-5 linear or branched chain saturated or unsaturated aliphatic alcohols and glycol monoalkyl ethers can be mentioned. Specifically, methanol, ethanol, n
-propanol, isopropanol, n-butanol,
inbutanol, sec-butanol, tert-butanol, n
-Amyl alcohol, isoamyl alcohol, activated amyl alcohol, tertiary amyl alcohol, 3-pentanol, tertiary amyl alcohol, fusel oil, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, prohillenc Examples include recall monomethyl ether and propylene glycol monoethyl ether, which may be used alone or in combination of two or more.

Regarding the composition of the developer of the present invention, 1 to 1
0 parts by weight, preferably 2 to 6 parts by weight of the solute.
parts by weight, preferably 0.1 to 1 part by weight, and 1 to 200 parts by weight, preferably 5 to 50 parts by weight of the monohydric alcohol of component (C).
A developer composition comprising adding parts by weight is preferred.

The developing solution of the present invention is prepared by dissolving a predetermined amount of a metal ion-free alkali in water, then adding a predetermined amount of a quaternary ammonium salt type cationic surfactant and a monohydric alcohol to this solution, Prepared by uniform mixing. At this time, the addition ratio of each component to water is appropriately selected depending on the type of these components and the properties of the target positive photoresist, but the specific addition ratio can be determined by a simple experiment. can.

Effects of the Invention The developer of the present invention uses an alkali containing no metal ions as a solute, and further contains a quaternary ammonium salt type cationic interface to improve dissolution selectivity between exposed and non-exposed areas of the resist film. A pH product containing an activator and m alcohols to improve the solubility of the exposed area of the resist film during development and prevent the formation of thin film residue or scum residue.
This is a positive photoresist developer consisting of an alkaline aqueous solution of 11 or more, which has extremely excellent dissolution selectivity for exposed areas and non-exposed areas, and has a cross-sectional shape of the resist film after development. Closer and improve resolution at the same time.

It also has the property of suppressing thin film residue and scum residue, which are particularly likely to occur in highly sensitive resists. Therefore, by using the developer of the present invention, it is possible to easily control the processing dimensions of the base substrate, including the dry etching process, in the semiconductor circuit element manufacturing process, especially when using a base substrate with steps, and the product characteristics. You can get excellent results.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples. - Hydroxyethyl) ammonium hydroxide (hereinafter abbreviated as THAH) and methylbis(2-hydroxyethyl)yacyanmonium chloride (manufactured by Lionarf, trade name KTHOQ) as a quaternary ammonium salt type cationic surfactant. , UAD c/+s)
, trimethylyacyanmonium chloride (manufactured by Lion Armor, trade name ARQ, UAD c/so), tributylmethylammonium chloride (hereinafter referred to as TBMAC)
), triamylmethylammonium chloride (hereinafter abbreviated as TAMAC!), and trihexylmethylammonium chloride (hereinafter abbreviated as THMAC), and alcohols such as ethanol and inopropyl alcohol (
A developing solution having the composition shown in the attached table was prepared using eight kinds of compounds: TECHNICAL PA), propatool, phthanol, ethylene glycol monoethyl ether, ethylene glycol, fluoropylene gellicol, and glycerin.

To prepare a developer, first, TMAH or THAI (TMAH or THAI) is dissolved in water to a predetermined concentration to prepare a TMAH or THAH-containing aqueous solution, and then this TMAH or THAI
Alternatively, this was carried out by adding predetermined parts by weight of a quaternary ammonium salt type cationic surfactant and alcohol to 100 parts by weight of THAH.

Next, using a 3-inch silicon wafer as a substrate, positive photoresists 0FPR-800 and 0FPR-500 were applied.
Spin code 0 (product name, manufactured by Tokyo Ohka Kogyo Co., Ltd.),
A resist film with a thickness of 1.3 μm was created.

Image exposure was performed using an exposure device (Canon PLA 500), and development was performed using each of the above-mentioned developers using the immersion method, followed by rinsing treatment using the immersion method, and the sensitivity, rate of film thickness reduction in non-exposed areas, and development were evaluated. The Taber angle of the cross-sectional shape of the subsequent resist pattern and the state of scum were measured or observed. The results are shown in the table.

The sensitivity is expressed in seconds as the minimum exposure time required to develop the resist film and faithfully reproduce the image. Then, the amount of film thickness reduction at that time was measured, and the resist taper angle was.

The cross-sectional shape of the resist pattern developed under the same conditions as above was measured using a scanning electron microscope, and the state of the scum is as follows:
After exposure for a sensitive time, the substrate was developed and the state of the substrate was observed using a scanning electron microscope.

As is clear from the table, 5 the developer of the present invention has excellent developer selectivity in terms of film thickness reduction rate in non-exposed areas and resist taper angle; be.

Claims (1)

[Scope of Claims] 1. A positive photoresist developer containing (A) an alkali containing no metal ions, (B) a quaternary ammonium salt type cationic surfactant, and (C) a monohydric alcohol. . 2. The developer according to claim 1, wherein the alkali compound containing no metal ions is at least one selected from tetramethylammonium hydroxide and trimethyl(2-hydroxyethyl)ammonium hydroxide. 3. The cationic surfactant is an alkyltrimethylammonium salt having an alkyl group having 2 to 20 carbon atoms,
dialkyldimethylammonium salt, alkyldimethylethylammonium salt, alkylmethyldi(hydroxyethyl)ammonium salt, alkyldimethylbenzylammonium salt, alkylamidopropyldimethylbenzylammonium salt, alkyl group-substituted phenoxyethoxyethyldimethylbenzylammonium salt, alkylpyridinium salt, The developer according to claim 1 or 2, which is at least one selected from alkylquinolinium salts, alkylisoquinolinium salts, alkylimidazolinium salts, and trialkylmethylammonium salts. . 4. The developer according to claim 3, wherein the cationic surfactant is methylbis(2-hydroxyethyl)cocyanmonium chloride. 5. The developer according to claim 3, wherein the cationic surfactant is trimethylyacyanmonium chloride. 6. The developer according to claim 1, 2, or 3, wherein the monohydric alcohol is at least one selected from alcohols having 4 or less carbon atoms and glycol monoalkyl ethers.