JPS58137836A - Processing agent for rubber resist - Google Patents

Abstract

PURPOSE:To obtain the titled processing agent capable of correctly reproducing a desired pattern, by effectively removing a rubber resist applied to a photoetching method, by blending a specified surfactant with a hydrocarbon solvent. CONSTITUTION:A processing agent is obtd. by blending 100pts.wt. hydrocarbon solvent such as aliphatic hydrocarbon (e.g., n-heptane), aromatic hydrocarbon (e.g., xylene) or alicyclic hydrocarbon with 0.005-5pts.wt. anionic surfactant such as alkylbenzenesulfonic acid and/or nonionic surfactant such as polyoxyethylenealkylphenyl ether. A rubber resist or a rubberlike material applied to a photoetching method can be easily removed with said processing agent, and the surface of the underlayer exposed by removing the resist can be made hydrophilic.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a processing agent used in photolithography of semiconductors,
More specifically, it is a processing agent such as a removal liquid for rubber-based overcoat materials, a developer for rubber-based resists, and a rinsing liquid for rubber-based resists or rubber-based overcoat materials, which are used for photographs using rubber-based resists or rubber-based materials. The purpose is to accurately reproduce the fine patterns of the etching process.

[Technical background of the invention and its problems]

One of the main technologies in semiconductor device manufacturing is photolithography, which uses various rubber-based materials and processing agents. One of these is an aluminum-based overcoat material, which is used to prevent defects such as chips from occurring in brittle resists such as phenol novolak-based positive resists during the exposure process, such as when aligning masks for contact exposure. This overcoat material is deposited on the applied resist film to protect the resist film during the exposure process, and the resist film is exposed to light through the overcoat material film. The applicant is
The use of non-photosensitive cyclized polyisoprene as such an overcoat material was proposed in Japanese Patent Application No. 56-67658. After exposure, this overcoat material made of non-photosensitive cyclized polyimprene is treated with an overcoat removal solution such as n-hebutane, xylene, or toluene, which dissolves the overcoat material and does not attack the underlying positive resist film. .

However, no matter what kind of aliphatic or aromatic solvent is used as the overcoat removal solution, the positive resist film after removing the overcoat material becomes hydrophobic and becomes uneven when developed with an aqueous positive resist developer. There was a problem in that it often caused uneven development and was not suitable for mass production.

A second rubber-based material used in photolithography is a well-known negative resist made of cyclized rubber.

A negative resist developer also contains an aliphatic or aromatic solvent similar to the overcoat removing solution, and when developed with such a developer, the underlying layer to be etched becomes hydrophobic. In this case as well, if the underlying layer to be etched is etched with an etchant that is an aqueous solution (for example, an NH4F aqueous solution in the case of a silicon oxide film), uneven etching tends to occur without being etched, which is a major problem in etching fine patterns. To improve this problem,
A method of mixing a lower alcohol or a surfactant into the NH4F etchant has been proposed, but the problems of changing the etching rate and creating a taper on the etched end face have not been solved.

[Purpose of the invention]

An object of the present invention is to provide a processing agent for rubber-based resists or rubber-based materials that can impart hydrophilicity to the lower layer surface after removing the rubber-based resists or rubber-based materials used in photolithography. It is in.

Another object of the present invention is to provide a processing solution for rubber-based resists or rubber-based materials that can achieve uniform reproducibility of fine patterns without uneven processing when processing lower-layer processed films such as positive resists and silicon oxide films. Our goal is to provide the following.

[Summary of the invention]

The present invention is characterized in that a surfactant is added to a processing agent for rubber resists or rubber materials used in photolithography. This processing agent includes a rubber-based resist developer, a rubber-based overcoat removal solution that covers the positive resist,
This includes a rinsing liquid after self-removal of rubber resist or rubber overcoat during development. This processing agent imparts hydrophilicity to the surface of the lower layer by adding a surfactant, and the hydrophilic lower layer, such as a positive resist or silicon oxide film, can be processed using an aqueous positive resist developer or a silicon oxide film. The surface is well wetted by the film etchant, and is developed or etched uniformly, leaving no uneven development or etching.

As previously pointed out, the conventional technique of adding a surfactant to a silicon oxide film etchant may be able to wet the surface well, but the surfactant will reduce the etching rate after it has performed its surface wetting action. This has a negative effect on the etching end face and the taper of the etched end surface. On the other hand, since the processing agent of the present invention does not require addition of a surfactant or the like to the etchant, fine patterns can be realized with good reproducibility.

As the rubber-based resist, natural rubber, cyclized rubber such as isoprene-based synthetic rubber, or butadiene-based synthetic rubber such as epoxidized polybutadiene is generally used. Furthermore, since rubber-based materials such as overcoat materials are non-photosensitive unlike resists, various natural rubbers and synthetic rubbers are widely used.

Rubber resist developer and overcoat removal solution include
One or a mixture of two or more of aliphatic hydrocarbons such as n-heptane, aromatic hydrocarbons such as xylene and toluene, and alicyclic hydrocarbons are used. As the rinsing liquid, butyl acetate, a trichlene-ethanol mixed solution, a trichlene-methanol mixed solution, etc. are used.

The surfactant used in the present invention may be any compound having lipophilicity and hydrophilic group in one molecule, and according to an investigation on cyclized polyimprene rubber, which is commonly used as a rubber resist or oval coating material. , anionic surfactants rather than cationic surfactants, such as alkylbenzene sulfonic acids, higher alcohol sulfates, alkylolamide sulfates, etc., and nonionic surfactants, such as polyoxyethylene alkylphenyl ether, Polyoxyethylene fatty acid ester, polyoxyethylene alkylaryl ether, etc. were particularly effective in imparting hydrophilicity. It is not impossible to add two or more of these surfactants, and favorable results can also be obtained.

The amount of surfactant added is 0.005 parts per 100 parts of processing agent.
~5 parts by weight may be used. This is because if the amount is less than 0.005 parts by weight, the effect will not be sufficient, and if it is 5 parts by weight or more, the effect of adding it will not be obtained. However, when using a nonionic surfactant as an overcoat material for positive resist,
If the amount of surfactant added is too large, it may partially react with water and attack the positive resist in unexposed areas, so the amount of surfactant added must be determined with due consideration to the dissolution properties of the positive resist used. be.

Among the treating agents of the present invention, it is most effective to use them as a rinsing liquid in order to impart hydrophilicity to the surface of the lower layer. This is because it is the rinsing liquid that ultimately treats the surface of the lower layer, and there is no possibility that the surfactant will adversely affect the developing action.

[Embodiments of the invention]

Examples are shown below to specifically demonstrate the present invention and its effects.

Example 1 Positive resist 0FPR-n was applied to the surface of an oxidized semiconductor substrate.
(trade name manufactured by Tokyo Ohka Co., Ltd.) to a thickness of 1.5 μm, and heated to 85°C.
・After pre-baking for 10 minutes, apply 1.0 O of non-photosensitive cyclized rubber overcoat material KOC-2 (trade name manufactured by Kanto Chemical)
The film was coated to a thickness of 100 pm, prebaked at 85° C. for 10 minutes, and then exposed for 10 seconds using a mask aligner PLA 500FA (trade name, manufactured by Canon). As an overcoat remover, one alkylbenzenesulfonic acid having an alkyl group having 10 carbon atoms, which is an anionic surfactant, is added to xylene.
% by weight was treated with a spray machine for 15 seconds to remove the overcoat material, dried, and developed with a positive developer TM-n (trade name manufactured by Tama Chemical Co., Ltd.).
I rinsed it. The oxide film was etched with an NH4F aqueous solution. When the pattern condition after development and etching was investigated, there was no uneven development or etching, and a fine pattern could be formed with good reproducibility. In addition, the results of applying it to a mass production line show that the rework rate due to overcoat removal, which used to be about 5 to 10 inches, has decreased to less than 1 inch, making it possible to apply overcoat materials stably and reproducibly in mass production. We were able to develop the resist.

Example 2 In the same photo-etching process as in Example 1, 0.5% by weight of polyoxyethylene alkyl ether'i having an alkyl group of 15 carbon atoms was added to xylene as an overcoat removal liquid using a nonionic surfactant. We were able to confirm similar results by using the same amount of

However, if the content of this polyoxyethylene alkyl ether is 1.5% by weight or more, the positive resist 0FP
Care must be taken since Rh (described above) will be partially dissolved.

Example 3 Negative resist OMR-83 was applied to the surface of the oxidized semiconductor substrate.
(Tokyo Ohka Co., Ltd. product name) was applied to a thickness of 13 μm at 85℃.
After pre-baking for 10 minutes, mask aligner PLA-
It was exposed for 10 seconds at 500FA (described above). Then n-
After developing the unexposed areas of the negative resist with hebutane, a rinsing solution containing 2.5% by weight of polyhydric alcohol fatty acid ester having 17 carbon atoms as a surfactant was added to butyl acetate as a rinse solution. After continuous spray cleaning for 15 seconds and post-baking at 150° C. for 10 minutes, the oxide film on the substrate was etched. Conventionally, when an aqueous solution containing only NH4F was used as an oxide film etchant, uneven etching occurred locally and it was difficult to remove the fine pattern, but in this embodiment, such a problem did not occur at all. Further, when the shape of the etched pattern was minutely inspected, it was found that the shape of the etched end face was extremely satisfactory.

Claims (1)

[Scope of Claims] 1. A processing agent for developing or removing a rubber resist or rubber material used in photolithography, which is selected from the group consisting of aliphatic hydrocarbons, aromatic hydrocarbons, and alicyclic hydrocarbons. A processing agent comprising one or more hydrocarbons and a surfactant. 2. The surfactant is one or more anionic surfactants selected from the group consisting of al2-benzene sulfonic acid, alkyl sulfate, and alkylolamide sulfate, and per 100 parts of the processing agent. 0.005 against
5 parts by weight of the processing agent according to claim 1. 6. The surfactant is one or more nonionic surfactants selected from the group consisting of polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, and polyoxyethylene alkylaryl ether, and the processing agent The processing agent according to claim 1, which is blended in an amount of 0.005 to 5 parts by weight per 100 parts. 4. A processing agent for cleaning rubber-based resists or rubber-based materials used in photolithography, characterized by comprising a cleaning organic liquid and a surfactant.