JPS61232454A - Positive type photoresist developing solution - Google Patents

Abstract

PURPOSE:To enhance selective solubility between the photoresist at the exposed areas and the nonexposed areas by incorporating a specified quaternary ammo nium compd. in a developing soln. of a positive type photoresist composed essentially of an org. base contg. no metal ion. CONSTITUTION:The positive type photoresist developing soln. capable of extreme ly enhancing the selective solubility of a resist film at the exposed areas and nonexposed areas, and at the same time, enhancing resolution, and restraining adhesion of the residues of the thin resist film and the scum is composed essen tially of the org. base contg. no metal ion in an amt. of 1-10pts.wt., preferably, 2-6 per 100pts.wt. of an aq. soln., further contains, in an amt. of 0.01-10, preferably, 0.1-10pts.wt. per 100pts.wt. of said solute, the quaternary ammonium compd. represented by the formula shown on the right in which R is <=8C alkyl; and X is halogen or OH. The developing soln. may contain other additives usually used, when needed, such as humectant, stabilizer, or solubilizing aid.

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 developing solution for positive photoresists which is particularly suitable for image formation using quinonediazide-based positive photoresists and which has excellent dissolution selectivity for exposed areas and non-exposed areas.

BACKGROUND ART Conventionally, when manufacturing semiconductor integrated circuit elements, integrated circuit manufacturing masks, printed wiring boards, printing plates, etc., selective processing is performed on the underlying substrate, such as by etching or diffusion. At this time, in order to selectively protect the unprocessed portions of the underlying substrate, a composition sensitive to actinic rays such as ultraviolet rays, X-rays, and electron beams (so-called photoresist) is used. A method has been adopted in which a film is formed using a film, and then an image is formed by imagewise exposure and development.

There are two types of photoresists: positive type and negative type. In the former type, exposed areas dissolve in a developer but unexposed areas do not, and in the latter type, the opposite type exists. 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 positive type photoresist based on chino/diazide, but when manufacturing semiconductor devices, using an alkaline aqueous solution containing metal ions as a developer has a negative impact on product characteristics. Therefore, a developing solution that does not contain metal ions, such as tetramethylammonium hydroxide (from M "Technical Discl.
our BulletinJ Volume 13, No. 7, No. 2
009 page, 1970) and Colin (U.S. Patent No. 4,
239,661) and the like are used.

By the way, as a developer for positive photoresist, a developer is used that easily dissolves the exposed areas of the photoresist film and does not easily dissolve the unexposed areas. It is important that the film has properties such that the image area hardly dissolves and the film thickness of the image area does not change before and after development.

However, in conventionally used developers,
The dissolution selectivity between exposed and non-exposed areas, so-called developer selectivity, is not sufficient, and as a result, the resist pattern obtained after development has a large decrease in resist film thickness, resulting in poor dimensional accuracy, and the resistance of the resist film after development. The cross-sectional shape of the substrate tends to be a trapezoid with a trailing tail, and the resolution is also lowered.As a result, it becomes difficult to control the processing dimensions of the underlying substrate in subsequent steps, such as dry etching. In particular, when a photoresist film is formed on a base substrate with steps, the film thickness is not the same in the convex and recessed portions of the 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 all of these problems, an aqueous alkaline developer containing no metal ions, such as an aqueous solution of tetraalkylammonium hydroxide, is used.
A method of adding a surfactant consisting of a quaternary ammonium compound such as hydroxy) coccyammonium chloride or trimethylcoccyanmonium chloride (JP-A-5B-
91431-A), or a method in which tetraalkylammonium or phosphonium, benzyltrialkylammonium or phosphonium, benzyltriarylammonium or haphosphonium, such as tetrapentylammonium, tetrabutylammonium or phosphonium, is completely added to the aqueous alkaline developer ( %Opened in 1978
-150949) has been proposed. However, in these methods, the developer selectivity is not necessarily sufficient, and the performance of the product is adversely affected, so that it cannot be said to be fully satisfactory.

Problems to be Solved by the Invention The purpose of the present invention is to solve such problems and to provide a material having excellent dissolution selectivity between exposed areas and non-exposed areas, which is particularly suitable for image formation using a quinonediazide-based positive photoresist. An object of the present invention is to provide a developer for positive type photoresists.

Means for Solving All Problems As a result of extensive research, the present inventors have found that the above object can be achieved by adding a specific quaternary ammonium compound to a conventional positive photoresist developer. Based on this finding, we have completed the present invention.

That is, the present invention provides a positive photoresist developer containing an organic base containing no metal ions as a main ingredient, which has a general formula (R in the formula is an alkyl group having 8 or less carbon atoms, a halogen atom, or a hydroxyl group). The present invention provides a positive photoresist developer characterized by adding a quaternary ammonium compound represented by:

As the metal ion-free organic base constituting the main ingredient of the developer of the present invention, those commonly used in conventional developers of this type can be used as they are. These include, for example, aryl and alkyl amines, including primary, secondary and tertiary amines in which the substituents are linear, branched or cyclic; alkylene amines such as 1,3-diaminopropane; Diamines, arylamines such as 4,4'-diaminodiphenylamine, amines such as bis-(dialkylamino)imines, and 3-5 rings in the ring skeleton.
heterocyclic bases having 5 carbon atoms and 1 or 2 heteroatoms selected from nitrogen, oxygen and sulfur, such as pyrrole, pyrrolidine, pyrrolidone, pyridine, morpholine, pyrazine, piperidine, oxazole, thiazole, etc. Alternatively, a quaternary ammonium base such as lower alkyl quaternary ammonium hydroxide may be used.

Among these, particularly preferred are tetramethylammonium hydroxide and trimethyl(2-hydroxyethyl)ammonium hydroxide (purine). Furthermore, the above-mentioned organic bases that do not contain metal ions may be used alone or in combination of two or more.

As the quaternary ammonium compound of the general formula I added to the developer of the present invention, R in the general formula has 3 to 5 carbon atoms.
trialkylmethylammonium compounds, such as tributylmethylammonium chloride, where the alkyl group of
Preferred are triamylmethylammonium chloride, triamylmethylammonium bromide, triproylmethylammonium iodide, and the like. These may be used alone or in combination of two or more.

By adding these quaternary ammonium compounds, the solubility of the unexposed area is significantly reduced, and the dissolution selectivity between the exposed area and the unexposed area is improved.

Regarding the composition of the developer of the present invention, the organic base (hereinafter referred to as solute) that does not contain metal ions is contained in an aqueous solution containing 1 to 10% by weight, preferably 2 to 6% by weight of solute. Quaternary ammonium compound 0.01-10
A developer composition containing 0.1'1 part by weight, preferably 0.1'1 part by weight, is preferred.

In addition to the above-mentioned components, the developer of the present invention may optionally contain other additives conventionally used in developer solutions, such as wetting agents,
Stabilizers, solubilizing agents, etc. can be added.

The developer of the present invention can be prepared, for example, by dissolving a predetermined amount of an organic base that does not contain metal ions in water, then adding a predetermined amount of a quaternary ammonium compound to this solution, and mixing uniformly. The ceremony will be held. 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 simple experiments. Can be done.

Effects of the Invention The developer of the present invention uses an organic base containing metal ions as a solute, and further contains a quaternary ammonium compound to improve dissolution selectivity between exposed and non-exposed areas of the resist film. , a positive photoresist developer consisting of an alkaline aqueous solution with a pH of 11 or more, which has significantly superior dissolution selectivity for exposed and non-exposed areas compared to conventional developers, and improves the cross-sectional shape of the resist film after development. The so-called resist pattern edges are made nearly vertical,
At the same time, it has the property of improving resolution and 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 becomes easy to control the processing dimensions of the base substrate, including the dry etching process, even when a base substrate with steps is used in the semiconductor circuit element manufacturing process, which may adversely affect product characteristics. It has no effect on

Example Next, the present invention will be explained in more detail with reference to examples.

Examples 1-7, Comparison Rows 1-2 Tetramethylammonium hydroxide (TMAH) and trimethylhydrochloride (2
-hydroxyethyl) ammonium hydroxide (TH
AH) and tributylmethylammonium chloride (TBMAO) as a quaternary ammonium compound.
Triamylmethylammonium chloride (TAMAO) and triamylmethylammonium bromide (TAMAB
) were used to prepare a developer having the composition shown in the attached table.

To prepare a developer, first dissolve TMAR or 'I'HAH'i aqueous solution in water to a predetermined concentration.
This was carried out by preparing an aqueous solution containing H or THAH, and then adding a predetermined part by weight of a quaternary ammonium compound to 100 parts by weight of the solute in this aqueous solution.

Next, using a 3-inch silicon wafer as a substrate, positive photoresists 0IFPR-800 and 0FPR-500 were applied.
Spin code 0 (product name, manufactured by Tokyo Ohka Kogyo Co., Ltd.),
A resist film with a film thickness of 1.3 μm was created, imagewise exposed using an exposure device (Canon PLA 5oo) 1z, and developed by the immersion method using each of the above-mentioned developers, -
A rinsing process was performed using a dipping method, and the sensitivity, rate of film thickness reduction in non-exposed areas, taper angle of the cross-sectional shape of the resist film, and scum condition 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. The amount of film thickness reduction at that time was measured, the resist taper angle was measured by observing the cross-sectional shape of the resist film developed under the same conditions as above with a scanning electron microscope, and the state of the scum was determined by the sensitivity. After exposure for a period of time, the substrate was developed and the state of the substrate was observed using a scanning electron microscope.

As is clear from the table, the developer of the present invention was found to be extremely superior to the conventional developer in terms of film thickness reduction rate in non-exposed areas and resist taper angle; It can be seen that there is no scum left.

Claims (1)

[Scope of Claims] 1. There are general formulas, mathematical formulas, chemical formulas, tables, etc. for positive photoresist developers whose main ingredient is an organic base that does not contain metal ions (R in the formula is an alkyl group having 8 or less carbon atoms) 1. A positive photoresist developer, characterized in that a quaternary ammonium compound represented by the following formula is added: X is a halogen atom or a hydroxyl group. 2. The positive photoresist developer according to claim 1, wherein R in the general formula is an alkyl group having 3 to 5 carbon atoms. 3. The positive-working photoresist developer according to claim 1, wherein the metal ion-free organic base is tetramethylammonium hydroxy, trimethyl(2-hydroxyethyl)ammonium hydroxide, or both.