JPS61270755A - Preparation of dry etching resistant both positive and negative type photoresist - Google Patents

Abstract

PURPOSE:To obtain a dry etching resistant photoresist usable as both of negative and positive types by successively laminating a photosensitive resin composition layer composed of a substance having quinonediazide structures and a silicone rubber layer, imagewise exposing it, and processing it with a base. CONSTITUTION:7503The photosensitive resin composition layer composed of a substance having quinone diazide structures, and the silicone rubber layer are successively laminated to form the photoresist for use in micropattern forma tion necessary for fabrication of semiconductors, magnetic bubble memory elements, integrated circuits, and the like. The photoresist is imagewise exposed and processed with a base, thus permitting dry etching resistance usable for both of negative and positive types to be obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The dry etch-resistant photoresist for both negative and positive use of the present invention can be used for forming fine patterns necessary for manufacturing semiconductor devices, magnetic bubble memory devices, integrated circuits, etc. be done.

[Conventional technology]

In the production of electronic components such as semiconductor elements and integrated circuits,
Microfabrication technology using etching is used. For example, a photoresist layer is formed on a silicon single crystal wafer by spin coating, and then a mask with a desired pattern is layered on top of the photoresist layer. After image formation, etching is performed to form a mask with a desired pattern. Line formation and window opening are being carried out. In the above-mentioned microfabrication technology, the precision of the product is largely determined by the performance of the photoresist used, such as resolution on the substrate, degree of photosensitivity, adhesion to the substrate, or resistance to etching.

There are two types of photoresists: negative resists in which exposed areas become insolubilized and positive resists in which exposed areas become soluble. Generally, negative resists are superior in sensitivity but inferior in resolution. On the other hand, positive resists have excellent resolution but are inferior in sensitivity and resistance to etching.

With the miniaturization of interconnections in semiconductor devices, dry etching is increasingly being used instead of the conventional wet etching for etching the underlying layer after patterning the resist layer. Therefore, resist materials are required to have strong resistance to dry etching. However, conventional resist materials, regardless of whether they are negative type or positive type, do not necessarily have sufficient resistance to dry etching, and it has been desired to improve their properties.

As a resist patterned by applying high-energy radiation such as an electron beam, the 2FIJ resist method is known, which includes 3i in the upper layer and uses an organic resist in the lower layer (J, Vac, Sci, Tech, 16.1977).
1979) ). In this case, the upper resist layer containing 81 is decomposed or cross-linked by high-energy radiation, and patterning occurs.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a photoresist that uses a so-called positive resist with good resolution and can act on both negative and positive resists, and in particular, to provide a photoresist with excellent resistance to dry etching. It is in.

[Means for solving problems]

In order to achieve the above object, the present invention consists of the following configuration.

Dry etching resistant for both negative and positive use, characterized in that a photoresist comprising a photosensitive resin composition containing a substance containing a quinonediazide structure as a constituent and a silicone rubber layer is provided in this order, and then subjected to image exposure and base treatment. sexual photoresist.

The photoresist of the present invention is composed of two layers: a layer of a photosensitive resin composition which plays a role in image formation and which has a substance containing a quinone diazide structure as a constituent component, and a silicone rubber layer which exhibits dry etching resistance.

Layer of the photosensitive resin composition of the present invention (hereinafter referred to as photosensitive layer)
is composed of a substance containing a known quinonediazide structure, and the substance containing a quinonediazide structure is a quinonediazide which is usually used in positive type phytoresists.

Such quinonediazides may be in the form of polymers, oligomers or monomers, such as quinonediazide sulfonic acid esters obtained by condensation with a compound having a hydroxyl group, or quinonediazide sulfonic acid amides obtained by condensation with amines.

Here, the amount of photodecomposition of quinonediazide units of a substance containing a quinonediazide structure means the infrared absorption spectrum (F
The amount of change due to exposure in the absorption intensity (area intensity of absorption spectrum) in the 2200 to 2000 Cm' region derived from the diazide group of quinone diazide in the photosensitive layer, that is, the amount of photodecomposition of the diazide group, was determined by T-I R-ATR method). It was determined based on the value of the unexposed photosensitive layer. Photodecomposition of quinonediazide is generally referred to for quinonediazides and is caused by the change from quinonediazide to carboxylic acid due to exposure to light. For example, naphthoquinone-1,2-diazide-5-sulfonic acid and phenol formaldehyde novolac resin are indene carboxylic acids.

The exposed area provided by the present invention is difficult to define unambiguously and varies depending on the amount of quinonediazide, irradiation light, etc.

The base used in the base treatment of the present invention means t=U, which is used in the ordinary chemical field, and is defined as a proton acceptor or an electron donor. The base may be either inorganic or organic.

Particularly preferred among these bases are organic bases, and among these, amine compounds are particularly preferred. These bases may be used alone or in a mixture, and in liquid or gas phase. In the case of a liquid, it is used, for example, in mW itself or in the form of a solution.

When used as a solution, the solvent may be water, an organic solvent, or a mixture of both. Alternatively, it may be combined with a developer.

Although the amount of base required for the treatment cannot be determined unambiguously, the minimum amount that is effective is clearly required. However, even if the amount is large, the effect will not be impaired in any way.

The time for the base treatment is not particularly limited and can be selected depending on the strength and concentration of the base, but usually the effect is immediately apparent upon contact with the treatment solution, and there is no change in the effect even if the treatment solution is in contact for a long time.

When processing in liquid form, immersion or coating on the surface may be sufficient. In the case of gas phase treatment, exposure to that atmosphere is sufficient.

The silicone rubber layer used in the present invention is mainly composed of a linear organic polysiloxane having the following repeating units and having a molecular weight of several thousand to several hundred thousand.

(Here, n is an integer of 2 or more, and R is an alkyl group, alkenyl group, or phenyl group having 1 to 10 carbon atoms.) Silicone rubber can be obtained by sparsely crosslinking such a linear polysiloxane. .

Crosslinking agents include acetoxysilane, ketoximesilane, alkoxysilane, aminosilane, amidosilane, and alkenyloxysilane, which are used in so-called air temperature (low temperature) curing silicone rubber, and are usually linear organic polysiloxanes with terminals. In combination with the water rti group, acetate-removed type, oxime-eliminated type, alcohol-eliminated type, respectively.
It becomes deamined type, deamidated type, and deketone type silicone rubber.

Additionally, a small amount of an organic tin compound is added to the silicone rubber as a catalyst.

Various materials may be used as a contact layer between the layers for adhesion between the photosensitive layer and the silicone rubber layer, and aminosilane compounds and organic titanate compounds are particularly preferred.

Instead of providing an adhesive layer between the photosensitive layer and the silicone rubber layer, an adhesive component may be added to the silicone rubber layer. Aminosilane compounds and precipitated titanate compounds can also be used as this additional adhesive component.

The silicone rubber layer that is the top layer of the photoresist has high resistance to oxygen plasma. By exposing the surface layer to oxygen plasma, S! It is thought that this is due to the formation of a 02-like film. Therefore, when using the material in various dry etching processes, it is extremely effective to perform oxygen plasma treatment in advance in forming fine patterns. In addition, due to its excellent resistance to dry etching, when used as a resist,
It is possible to reduce the film thickness, and as a result, pattern resolution improves, which is advantageous in processing.

When the photoresist of the present invention is used for pattern formation of semiconductor elements, etc., the photosensitive layer composition and the silicone rubber layer composition are each dissolved in an organic solvent. After spin-coding these onto the element substrate, drying and curing at appropriate temperature conditions, in the case of negative type use, the entire surface is exposed for a short time, image exposure is performed through the desired pattern, and base treatment is performed. After that, it is developed with a suitable solvent.

On the other hand, in the case of positive type use, only short-time image exposure is performed, followed by base treatment and solvent development.

The light source for exposure may be one that generates light in a wavelength range that converts quinonediazide into carboxylic acid. Examples include ultra-high pressure mercury lamps, carbon arc lamps, metal halide lamps, xenon lamps, and chemical lamps.

As developing solvents, aliphatic hydrocarbons (hexane, heptane, "Isopar E, H, G" (EsSo Ch
(4ml cal) or gasoline, kerosene, etc.), aromatic hydrocarbons (toluene, xylene, etc.),
It is preferable to use a halogenated hydrocarbon (such as trichlene) to which the following solvent is added.

Alcohols (methanol, ethanol, water, etc.).

Ethers (methyl cellosolve, ethyl cellosolve, butyl cellosolve, ethyl carpitolxane, etc.).

Ketones (acetone, methyl ethyl ketone, etc.) Esters (ethyl acetate, methyl cellosolve acetate, cellosolve acetate, carpitol acetate, etc.).

In the present invention, it is considered that at least a portion of the substance containing the quinonediazide structure constituting the photosensitive layer is modified by the action of the base, thereby improving the adhesive strength between the silicone rubber layer and the photosensitive layer and the solvent resistance of the photosensitive layer. In other words, the change in the photosensitive layer due to the base treatment can be interpreted as a change in the solvent resistance of the photosensitive layer and a change in the adhesiveness between the photosensitive layer and the silicone rubber layer.

It is thought that the carboxylic acid produced from quinonediazide by photolysis acts to attract the base into the layer in order to selectively interact with the base and quinonediazide.

This effect cannot be expected in areas where carboxylic acid components have been generated due to the above exposure, or in completely unexposed areas where no carboxylic acid has been generated. This is because the adhesion between the photosensitive layer and the silicone rubber layer is weak and the photosensitive layer is Since the solvent resistance is also poor, the corresponding silicone rubber layer or photosensitive layer will be removed along with the developing process.However, if the photosensitive layer is processed in advance to be insoluble in the developing solvent, for example by adding a polyisocyanate compound. If a crosslinked structure is created in advance, only the silicone rubber layer can be removed, leaving the photosensitive layer behind.

In the present invention, the upper silicone rubber layer is non-photosensitive, and the effect of pattern formation due to light is due to the action of the lower photosensitive layer, which is then treated with a base and controlling the exposure amount to improve oxygen plasma resistance. It has the characteristic that it enables good patterning of the silicone rubber layer. The underlying photosensitive resin layer is removed by ion etching using oxygen gas, and the silicone rubber layer serves as a mask for this process.

Such a method is also useful as a method for processing the underlying base that fills in the difference in level.

[Example] Aspects of the present invention will be illustrated and explained below using Examples, but the invention is not limited thereto.

Example 1 A solution of a photosensitive resin composition having the following composition was spin coated to form a 2 μm thick layer on a silicon wafer.

Partial ester of naphthoquinone-1,2-diazide-5-sulfonic acid and phenol formaldehyde novolac resin Esterification degree 47% by CIR method)
100 parts 4, 4°-diphenylmethane diisocyanate 30 parts by weight dibutyltin dilaurate 0.2 parts dioxane 2000 parts after coating, 120°C
, heat treated for 2 minutes.

Subsequently, a silicone rubber composition having the following composition was spin-coded on top of this, and cured with moist heat at 120°C for 2 minutes to give a 1μ
m layers were provided.

Dimethylpolysiloxane (MW approx. 25,000, terminal hydroxyl group) 100-bipartite vinyl tris(methyl ethyl ketoxime) silane
8 parts by weight dibutyltin diacetate 0
．． 2 parts by weight γ-7 minobrobyltrimethoxysilane 1 part by weight "Isopar E" (Exxon Chemical Bag, aliphatic hydrocarbon solvent) 1800 parts by weight The thus formed photoresist was coated with a metal halide lamp (Iwasaki Electric Co., Ltd.) The entire surface was exposed to light for 6 seconds at a distance of 1 m using an Idol Fin 2000 manufactured by Oak Seisakusho Co., Ltd. at an illuminance of 1 mW/-. It was confirmed by an infrared spectrum that 18 mol C36 of quinone diazide in the photosensitive layer was photodecomposed to produce a carboxylic acid component.

A negative film having a circuit pattern was passed through the entire surface of the foot resist exposed in this way, and image exposure was carried out for 60 seconds from a distance of 1 m using the metal halide lamp described above. Then "Isopar" H/Butyl Calpitol/Ethyl Cellosolve/Ethanolamine-90151510,1
The silicone rubber layer was immersed in a base processing solution with a 0/40/40 ratio for 1 minute, then immersed in a developer with a 0/40/40 ratio of "ISOPAR" H/butylcarpitol, and then exposed in an image by rubbing the silicone rubber layer lightly with a pad. The silicone rubber layer in the exposed areas was removed and the photosensitive surface was exposed.On the other hand, the silicone rubber layer remained firmly in the areas where only the entire surface was exposed.

The silicone rubber layer patterned in this way had excellent oxygen plasma resistance.

Example 2 In the same manner as in Example 1, a photosensitive resin layer and a silicone rubber layer were coated in this order on a silicon wafer, and then a positive film with a circuit pattern was passed through it, and the metal halide lamp used in Example 1 was used to coat it for 1 m. 11mW1 from the distance of
Exposure was performed for 9 seconds at an illuminance of 0rf. Next, “Isopar”
H/propylene glycol monomethyl ether/ethyl cellosolve/monoethanolamine-90151510
．． By immersing it in a developer containing a base at a weight ratio of 3 and rubbing it lightly with a cotton pad, the silicone rubber layer in the unexposed areas is removed and the surface of the photosensitive layer is exposed.

The silicone rubber layer thus formed had excellent oxygen plasma resistance.

[Effects of the Invention] (1) Since a non-photosensitive silicone rubber layer is used, easily available silicone rubber having various physical properties can be used. Therefore, a resist film with high dry etching resistance can be easily formed.

(2) Utilizing the characteristics of the photosensitive resin layer containing the quinone diazide structure, it can be used for both positive and negative types with simple base treatment.

(3) When using a positive type, the patterning exposure is very short. That is, it can be used as a highly sensitive resist.

(4) Since it is used in large area exposure systems using ultra-high pressure mercury lamps or metal halide lamps, it can also be used for things such as oxygen plasma etching of plastic surfaces.

Claims (3)

[Claims] (1) A photoresist for both negative and positive use, characterized in that a photoresist comprising a layer of a photosensitive resin composition containing a substance containing a quinonediazide structure and a silicone rubber layer in this order is imagewise exposed and treated with a base. A method for producing a dry etching resistant photoresist. (2) After exposing the entire surface to light in an amount that photodecomposes 5 to 60 mol% of the quinonediazide units of the substance containing the quinonediazide structure in the layer of the photosensitive resin composition, the photosensitive resin composition in the exposed area is Image exposure is applied in an amount sufficient to photodecompose at least 70 mol% of the quinone diazide units of the substance containing the quinone diazide structure in the layer, or conversely, after image exposure, the entire surface including the non-image area is exposed, and then A method for producing a dry etching resistant photoresist for both negative and positive use according to claim 1, characterized in that development is carried out after base treatment or development is carried out simultaneously with base treatment. (3) Image exposure is carried out in an amount sufficient to photodecompose 5 to 60 mol % of the quinone diazide units of the substance containing the quinone diazide structure in the layer of the photosensitive resin composition, followed by base treatment and development or base treatment. A method for producing a dry etching resistant photoresist for both negative and positive use according to claim (1), characterized in that development is carried out simultaneously.