JPS63170640A - Developer for positive photoresist - Google Patents

Abstract

PURPOSE:To form a good pattern remaining no scum nor residual thin film after development and to enable processing with good dimensional accuracy in the stage of etching during post-treatment by adding a specified nonionic surface active agent in a specified proportion to a developer for positive photoresist consisting primarily of an org. base. CONSTITUTION:50-5,000ppm at least one kind of nonionic surface active agent selected from nonionic surface active agents, expressed by the formula I is added to a developer for positive photoresist consisting primarily of an org. base contg. no metal ion. In the formula I, at least one of R1 and R2 is(are) 4-20C alkyl group and another is H atom; (n) is an integer 8-30. By adding an org. base consisting primarily of a specified nonionic surface active agent having superior permeability, detergency, and solubility in the development of a positive photoresist, the permeability of the developer into fine pattern parts is elevated, and scum and thin film are removed from the substrate due to the detergency and solubility of the developer.

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 is capable of forming a good pattern without thin film residue or scum in the fine parts of the resist pattern after development, and is suitable for improving the resolution of fine through holes. This invention relates to a developer for positive photoresists.

Conventional technology Traditionally, in the production of semiconductor integrated circuit elements, integrated circuit manufacturing masks, printed wiring boards, printing plates, etc., it has been used to selectively protect the underlying substrate when performing etching, diffusion, etc. For this purpose, a widely used method is to form a film using a composition sensitive to actinic radiation such as ultraviolet rays, X-rays, and electron beams, so-called radiation-sensitive resist, and then imagewise expose and develop the film to form an image. .

Among these radiation-sensitive resists, those that are particularly sensitive to ultraviolet rays are generally called photoresists, and there are two types of photoresists: positive type and negative type. It is a type that does not dissolve.
The latter is the opposite type. An alternative to the former positive type photoresist is a combination of an alkali-soluble novolac resin as a binder and a naphthoquinone diazide compound as a photodegrading agent. An alkaline aqueous solution is used as a developer for this naphthoquinone diazide compound-based positive photoresist, but when manufacturing semiconductor devices, an alkaline aqueous solution containing metal ions is used as a developer to obtain product characteristics of the semiconductor device. Because it has a negative impact on

A developer that does not contain metal ions, such as tetramethylammonium hydroxide [IBM Technical
Discrowsia Biuretain (More M Tech
nical Disclosure Bulletin
) J Volume 3, No. 7, Page 2009 (1970
) and choline (US Pat. No. 4,239,661).

Recently, the integration of semiconductor devices has rapidly progressed, and the control line width is now required to be around 1 μm or even less than 1 μm.

One of the major problems associated with forming images using positive photoresists is that when forming images in such fine pattern areas, especially fine contact holes, the above-mentioned alkaline developer that does not contain metal ions is required. If a type of developer is used to improve wettability by adding a surfactant to the surface of the film, scum and thin film residues may be generated in exposed pattern areas that should be dissolved. Even if overexposure or overdevelopment is performed to avoid such a phenomenon, it is difficult to form a clear image. Therefore, scum and thin film residue are usually removed by light treatment with oxygen plasma or sputtering, but with these methods, it is difficult to control the oxygen plasma treatment9.
In areas where the resist shape has deteriorated or in pattern areas such as contact holes of around 1 μm, the uniformity of the oxygen plasma treatment is low, making it difficult to remove scum smoothly.

If the base is processed, such as dry etching, with such scum residue or thin film residue present,
This may lead to undesirable situations such as insufficient etching or poor dimensional accuracy or etched shape.

Problems to be Solved by the Invention The purpose of the present invention is to solve such problems, and to provide a method suitable for forming a pattern using a positive photoresist consisting of a combination of a naphthoquinone diazide compound and an alkali-soluble novolac resin. In other words, in the formation of fine patterns of around 1 μm or less and the formation of fine contact holes, it is possible to form good patterns without scum or thin film residue after development processing, and to process with high dimensional accuracy during etching in the subsequent process. Another object of the present invention is to provide a developer for positive photoresists.

Means for Solving the Problems The present inventors have conducted intensive research to develop a developer for positive photoresist having such favorable properties. We have discovered that the objective can be achieved by adding a specific nonionic surfactant in a predetermined ratio to a positive photoresist developer, and based on this knowledge, we have accomplished the present invention. It's arrived.

That is, the non-invention is based on a positive photoresist developer containing an organic base containing no metal ions as a main ingredient. , others are hydrogen atoms, n
is an integer of 8 to 30. This is what we provide.

The present invention will be explained in detail below.

In the present invention, the positive photoresist developer containing an organic base that does not contain metal ions as a main ingredient may be prepared by dissolving only an organic base that does not contain metal ions, which is the main ingredient of the developer, in water. If desired, this solution may contain additives commonly used in conventional developing solutions.

The organic bases that do not contain metal ions and are the main ingredients of the developer include those conventionally used in this type of developer, such as primary and secondary bases with linear, branched or cyclic substituents. and aryl and alkylamines, including tertiary amines, such as alkylene diamines such as 1,3-diaminopropane, arylamines such as 4,4'-diaminodiphenylamine, and bis(dialkylamino)imines. , heterocyclic bases having 3 to 5 carbon atoms and 1 or 2 atoms selected from nitrogen, oxygen and sulfur in the backbone, such as pyrrole, pyrrolidine, pyrrolidine,
Lower alkyl quaternary ammonium bases such as pyridine, morpholino, pyran/piperidine, oxazole, and thiazole are used. Particularly preferred among these are tetramethylammonium hydroxide and trimethyl(2-hydroxyethyl)ammonium hydroxide (choline). Further, each of the above-mentioned organic bases that do not contain metal ions may be used alone, or
You may use it in combination of 2 m or more.

Additives commonly used in conventional developing solutions that can be added as desired include, for example, wetting agents, stabilizers, and dissolution aids, as well as the ability to dissolve the exposed and unexposed areas of a positive photoresist film. Examples include cationic surfactants for improving properties. These may be added individually or in combination of two or more.

In the present invention, the general formula (R1, R2 and n in the formula have the same meanings as above) is added to the developer containing the above-mentioned metal ion-free organic base and various additives added as desired. It is necessary to add the indicated nonionic surfactants. Examples of the nonionic surfactant include polyoxyethylene alkyl ether and polyoxyethylene secondary alcohol ether.

These may be used alone or in combination of two or more.

The amount of the nonionic surfactant added is 50 to 5000 ppm, preferably 500 to 30 ppm, based on the developer.
00 ppm. This addition amount is 50pp
If it is less than 50 m, the wettability effect will not be sufficiently exhibited, the resolution will be low, and scum or thin film residue will be likely to occur.
If it exceeds 0.00 ppm, the dissolution selectivity between the exposed area and the unexposed area will deteriorate, the resist shape after development will deteriorate, and the desired resist pattern 7 shape will not be obtained, and the remaining film rate in the unexposed area will decrease. descend.

The positive photoresist targeted by the developer of the present invention is not particularly limited as long as it is a positive type photoresist in which the exposed area dissolves in the alkaline developer and the non-exposed area does not dissolve, but it is preferable. A positive photoresist is one that contains an alkali-soluble novolac resin and a naphthoquinone diazide compound as its constituent components.

Effects of the Invention The inventive developer for positive photoresists is a developer containing an organic base as a main ingredient and a specific nonionic surfactant that has excellent permeability, detergency, and solubility in the development process of positive photoresists. By adding it to the developer, it increases the permeability of the developer into the fine pattern area, and its washability and solubility eliminates scum and thin films that are thought to be reactants of the resin and photodegrading agent that are the constituent components of positive photoresist. It can be removed from the substrate, and a resist pattern without scum or thin film residue can be obtained without deterioration of shape or reduction in resolution even in 1 μm fine pattern portions and contact hole portions.

In addition, due to the surface active effect of the nonionic surfactant, the wettability when supplying the developer to the resist surface is the same as above, reducing the variation in the phenomenon, and it can be used for 1@ development processing. This has the effect that the amount of developing solution used can be reduced.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

Examples 1 to 14 A developer solution was prepared by adding a nonionic surfactant as shown in the attached table to a 2.38-t water solution of tetramethylammonium hydroxide.

0FPR-5000 (a positive photoresist containing an alkali-meltable novolak resin and a naphthoquinone diazide compound as constituent components) was applied to a 4-inch silicon wafer.
manufactured by Tokyo Ohka Kogyo Co., Ltd.) with a film thickness of 1.3 μm using a spinner.
After coating it, heat it to 110℃ on a hot plate.
Pre-bake for %90 seconds, then reduce the projection exposure device DSW-
4800 (manufactured by GCiA) - Exposure processing was performed through a test chart reticle. Then, using a stationary paddle type development device, development was carried out at a temperature of 23 ° C. for 65 seconds using the developer prepared as described above. After the treatment, the resist pattern was rinsed with pure water and dried.The resist pattern thus obtained was observed, and the results are shown in the table.

/' , / , / Comparative example developer does not contain nonionic surfactant 2.38
As a result of observing the resist pattern obtained by the same developing operation as in Examples 1 to 14 using a t% wt% tetramethylammonium hydroxide aqueous solution, a large amount of scum was observed.

Claims (1)

[Scope of Claims] 1. A positive photoresist developer based on an organic base that does not contain metal ions has a general formula ▲ mathematical formula, chemical formula, table, etc. ▼ (At least one of R_1 and R_2 in the formula is an alkyl group having 4 to 20 carbon atoms, and the others are hydrogen atoms,
(n is an integer of 8 to 30) A positive photoresist developer, characterized in that it contains at least one nonionic surfactant represented by the following formula (n is an integer of 8 to 30) in a proportion of 50 to 5000 ppm.