KR910005031B1 - Photo sensitive composition - Google Patents

Abstract

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Description

Photosensitive composition

The present invention relates to a photosensitive composition that is sensitive to deep UV and can be formed into a high precision fine photoresist pattern.

The invention also relates to silicon-containing photosensitive compositions, in particular silicon-containing photosensitive compositions having high oxygen-oxygen-RIE resistance that can be dissolved in alkali and can be used as the top layer in a two-layer resist system.

Fine patterning of the photoresist layer formed on the substrate is one of the most important steps in the manufacture of semiconductor devices.

Photolithography has been used to perform fine patterning of photoresist layers, which involves exposing the substrate to G-line (wavelength: 436 nm).

The smallest stroke width that G-line exposure can provide is 0.5-0.6 μm.

In recent years, the demand for semiconductor devices having a high integration density has increased, so that finer patterning of the photoresist layer is required.

In order to form finer patterning on the photoresist layer, light having a wavelength shorter than visible light was irradiated onto the photoresist layer. One such light source is an excimer laser capable of emitting deep UV light with a specific wavelength. Among these lasers, KrF excimer lasers that generate light with a wavelength of 248 nm have attracted much attention. Several types of cyclic diketones are known to be very sensitive to light with a wavelength of 248 nm. Resists comprising cyclic diketones used as photosensitizers become alkaline soluble when exposed to UV rays having a wavelength of 248 nm.

The exposed portion of this resist is developed by developing with an alkaline solution and all such resists are positive type and negative type resists containing such cyclic diketones are not known. Conventional positive type photoresist containing naphthquinone diazide absorbs a lot of light with a wavelength of 248 nm, so light irradiated onto a layer formed by any of these photoresist becomes weaker and deeper as the layer goes deeper. It is hard to reach the bottom of the surface (light does not reach the surface of the formed substrate of the resist layer). Thus, the resist layer has a triangular pattern in cross section after development of the layer exposed to light of 248 nm wavelength. If the semiconductor substrate is etched using this layer as an etching mask, it is impossible to faithfully transfer the resist pattern onto the substrate. In order to increase the integration density of the semiconductor device, it is necessary not only to transfer the fine etching pattern to the substrate but also to arrange the multi-layer interconnection of the elements of the device, that is, the elements in three dimensions.

In order to form a multi-layer interconnected device on a substrate by photolithography, a photoresist pattern must be formed on a semiconductor layer that has a stepped portion of the photoresist pattern and is not flat. In order to faithfully form the resist pattern, the resist layer must be thick enough to flatten the resist surface, where the thicker the resist layer, the lower the resolution of the resist pattern. One known method for solving this problem is to use a multilayer resist system. This resist system has two or more resist layers alternated with each other.

The top layer is first patterned and then each of its bottom layers is patterned in turn using its top layer as an etching mask. The best used multilayer resist system is a three layer resist system with an upper layer, an intermediate layer and a lower layer. The lower layer, known as a planarization layer, is formed on the surface of the semiconductor substrate and is not flat because the elements of the semiconductor device are formed thereon. The lower layer fills the gap between the devices and has a relatively thick and flat upper layer. Because of the underlying layer, the exposure is absorbed and not reflected from the substrate. The reflected light reduces the resolution of the upper resist pattern. The upper layer serves as a photosensitive layer and is used as an etching mask for patterning the intermediate layer (the intermediate layer is used as an etching mask for patterning the lower layer). The underlayer is patterned by reactive ion etching (RIE) where oxygen-plasma is applied to the layer. Thus, the intermediate layer forming the resist is oxygen resistant, that is, high oxygen-reactive ion etchability (RIE).

Three layer resistor systems are preferred in that they have stepped portions and sufficiently fine etching patterns can be formed on uneven semiconductor surfaces, but etching must be repeated to form etching patterns on the semiconductor surfaces. Thus, the use of a three layer resist system makes the manufacture of semiconductor devices extremely complex. Therefore, a two layer resist system having an upper layer serving as top imaging of an intermediate layer and a three layer resist system has been proposed, which reduces the number of etchings required to fabricate a two layer resist system semiconductor device.

The upper layer is most often made of a silicone containing polymer having sufficient sensitivity and suitable oxygen RIE resistance, such polymers are known as chloromethylated polysiloxanes and the like. However, in a two-layer system, the organic solvent should be used as a developer for the silicon-containing resist, and the use of the organic solvent may cause problems. The solvent expands the resist pattern formed by the development and the resist pattern inevitably has the desired precision. can not do it.

It is an object of the present invention to provide a photosensitive composition which has high sensitivity to deep UV rays which are disturbed from UV rays, in particular KrF excimer laser, and which has a wavelength of 248 nm, and which can be formed into a high precision fine photoresist pattern.

Another object of the present invention is to provide a silicone-containing photosensitive composition which is alkali soluble and exhibits high photosensitivity and high oxygen resistance RIE.

According to the present invention, there is provided a first photosensitive composition comprising an alkali-soluble resin and a photosensitive agent represented by the following general formula (I).

Wherein R ₁ and R ₂ are an unsubstituted or substituted alkyl group having _{1 to} 20 carbon atoms, an unsubstituted alkoxy group or an unsubstituted or substituted aryl group, an unsubstituted or substituted aryloxy group, or an unsubstituted or substituted group. An anilino group is shown.

기를 가지며 감광제로 사용되는 알칼리 가용성 수지 및 방향족 화합물을 포함하는 두 번째 감광성 조성물이 제공된다. 또한 본 발명에 따르면 알칼리 가용성 수지와 4-12개의 탄소원자와 1-4개의

를 가지는 지방족 화합물 또는 사이클릭 화합물인 감광제를 포함하는 세 번째의 감광성 조성물이 제공된다.According to the invention is directly bonded to the benzene ring

A second photosensitive composition is provided having a group and comprising an alkali soluble resin and an aromatic compound used as a photosensitive agent. Also according to the present invention are alkali-soluble resins and 4-12 carbon atoms and 1-4

There is provided a third photosensitive composition comprising a photosensitive agent which is an aliphatic compound or a cyclic compound having a compound.

The three compositions can be suitably used as components of a negative type of resist. Resists comprising any of these compositions can be formed into a high precision fine photoresist pattern that is emitted from a KrF excimer laser and is sensitive to raw UV rays having a wavelength of 248 nm. Preferably, the alkali-soluble resin contained in any of the above-mentioned compositions has a transmittance of 50% or more in light having a wavelength of 248 nm when made into a film having a thickness of 1.0 mu m. When the composition comprises such a resin, light irradiated on one surface of the resist layer made of the composition and light having a wavelength of 248 nm can pass through the resist layer of the composition, reaching far enough from the surface of the resist layer. . Thus, a resist layer made of the composition may be formed into a resist pattern with openings that are straight and have vertical walls.

According to this invention, silicone-containing alkali-soluble resin; There is provided a silicon-containing photosensitive composition comprising a photosensitizer selected from the group consisting of silicon-containing naphthoquinone diazide, silicon-containing azide and the compound represented by the following general formula (II).

In the formula, R ₁ -R ₄ represents a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms of hydrogen, or a substituted or unsubstituted allyl group, or a substituted or unsubstituted silyl group. The silicon-containing photosensitive composition may be used as a photoresist material having sufficient oxygen resistance RIE and capable of forming an upper layer in a two layer resist system.

The upper layer made of this photoresist can be successfully processed to form a clear resist pattern when an alkaline developer is added, and the upper layer does not expand because no organic solvent is used as the developer.

The photosensitive composition according to the present invention comprises an alkali soluble resin, which is preferably a polymer comprising a polymer or a carboxyl group including an allyl group having a hydroxyl group introduced therein, among which phenolic novolak: cresol novolak: xylene novo Rock: vinyl-phenol resin: isopropenyl-phenol resin: vinylphenol monomer and / or copolymer with a compound selected from isopropenyl-phenylmonomer acrylic acid derivative, methacrylic acid derivative, acrylonitrile and styrene derivative: acrylic acid or meta Copolymers of cyclic acid and acrylonitrile or styrene derivatives: copolymers of malonic acid and vinyl ethers;

Alternatively alkali-soluble resin,

A. A polymer comprising silicone introduced into the phenyl group of novolak.

B. Polymers containing silicones introduced into ether groups with several OH groups of novolak.

C. A polymer comprising silicone introduced as an ether group to the OH group of a vinylphenol resin.

D. A polymer comprising silicone introduced into the methylene group of novolak.

E. A polymer with a phenyl group introduced into the siloxane bond.

F. A polymer comprising silicone introduced into a methacrylic resin.

It may be a resin containing a silicone such as. This silicone contains. Alkali-soluble resin is represented by the formula of Table 1.

In polymer B, novolak may be substituted with isopropenyl-phenolic resin. Similarly, in polymer C, vinyl-phenolic resin may be substituted with isopropylene-phenolic resin. In polymers B and C, silicone is not an ether group but an ester group. OH groups can be introduced, and in polymer F the methacryl resin can be substituted by an acrylic resin. Alternatively, the silicone-containing, alkali-soluble resin is a copolymer of a polyvinylphenol having a silicone-containing group such as a silicone-containing alkali group introduced into the benzene ring and a compound selected from the group consisting of acrylic acid, methacrylic acid derivatives, acrylonitrile and styrene derivatives. Can be. Preferably, the alkali-soluble resin contained in certain photosensitive compositions according to the present invention is a resin having a transmittance of 50% or more to light having a wavelength of 248 nm when made into a film having a thickness of 1.0 μm. When a photoresist layer comprising an alkali-soluble resin having a transmittance of less than 50% to the specific light when made into a 1.0 μm film is exposed to this specific light, the light resist with sufficient intensity is directed away from the exposed surface. It becomes impossible to reach the surface, which impedes the formation of a good photoresist pattern.

One of the alkali-soluble resins satisfying the above-mentioned conditions is a compound selected from the group consisting of isopropenylphenol, polyvinylphenol, polyvinyl phenol having a silicone compound (for example, a silicon-containing alkyl group) introduced into the benzene ring: and Copolymers consisting of compounds selected from the group consisting of styrene, acrylonitrile, methyl methacrylate and methacrylate.

The first photosensitive composition according to the present invention comprises a compound represented by the following general formula (I) and used as a photosensitive agent.

Wherein R ₁ and R ₂ are unsubstituted or substituted alkyl groups having 1-20 carbon atoms, unsubstituted or substituted alkoxy groups having 1-20 carbon atoms, unsubstituted or substituted aryl groups, unsubstituted or substituted , An aryloxy group, or an unsubstituted or substituted aninolin group. Preferred as the aryl group are phenoxy group, cyano phenoxy group, hydroxy phenoxy group, methoxy phenoxy group and the like.

The substituent of the substituted alkyl group or substituted alkoxy introduced as R ₁ or R ₂ may be selected from the group consisting of halogen atom, unsaturated group, carbonyl group, carboxyl group, nitrile group, thioether group, thioester group, alkyl group and alkoxy group. . Substituents of a substituted allyl group, aryloxy group or an alino group introduced as R ₁ or R ₂ are a group consisting of a halogen atom, an unsaturated group, a carbonyl group, a carboxyl group, a nitrile group, a thioether group, a thioester group, an alkyl group and an alkoxy group Can be selected from. In addition, the substituent of the substituted alkyl group, substituted alkoxy group, substituted aryl group, substituted aryloxy group, or substituted alinino group introduced as R ₁ or R ₂ may include silicone.

It may be represented by a photosensitizer represented by the general formula (I) of Table 2 wherein R ₁ and R ₂ is an unsubstituted or substituted alkyl group having 1-20 carbon atoms, an unsubstituted or substituted having 1-20 carbon atoms An alkoxy group, an unsubstituted or substituted allyl group, an unsubstituted or substituted aryloxy group or an unsubstituted or substituted anilino group. Products prepared by the reaction between any of the three compounds and the phenolic resin can also be used as photosensitizers.

Represents a compound which can be used as a photosensitizer represented by the general formula (I) in Table 3, wherein R ₁ or R ₂ has 1-20 carbon atoms and substituted alcohol group containing silicon or substituted aryl containing silicon Qi.

The first photosensitive composition according to the invention preferably comprises 100 parts by weight of alkali soluble resin and 1-100 parts by weight of a photosensitizer. If the composition in which the photosensitive agent is used in less than 1 part by weight does not have suitable photosensitivity, that part of the photosensitive layer made of the exposed composition may not be sufficiently dissolved in the developer. On the other hand, when more than 100 parts by weight of the photosensitizer is used the composition is in some cases poor applicability.

기를 가지며 감광제로 사용되는 방향족 화합물을 포함한다.The second photosensitive composition according to the present invention is an alkali soluble resin and a benzene ring is directly bonded

Aromatic compounds having groups and used as photosensitizers.

Diazo compounds represented by the following general formulas (III) to (V) can be used as photosensitizers:

Wherein R represents hydrogen, an unsubstituted or substituted alkyl group having 1-10 carbon atoms, an unsubstituted or substituted alcohol group having 1-10 carbon atoms, m is an integer ranging from 1-6 and n is 0- It is an integer in the range of 5, except that 1 + m + n = 6.

Wherein R represents hydrogen, an unsubstituted or substituted alkyl group having 1-10 elements, an unsubstituted or substituted alkoxy group having 1-10 carbon atoms, and is represented by 1. 1 ', m, m', n and n ' Is an integer in the range 0-5 (where 1 + m + n = 1 '+ m' + n '= 5 and m + m' = 0).

Wherein R represents an unsubstituted or substituted alkoxy group having 1 to 10 carbon atoms of hydrogen, m 'represents an integer ranging from 1-5, and 1 and n represent an integer ranging from 0-4, provided that 1 + m + n = 5).

The unsubstituted or substituted alkyl group having 1-10 carbon atoms used as R in General Formulas (III)-(V) is methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl , ter-butyl group, n-pentyl group, n-hexyl group, cyclohexyl group, n-octyl group, n-nonyl group, n-decanyl group and the like. The unsubstituted or substituted alkoxy group having 1-10 carbon atoms used as R in General Formulas (III)-(V) may be a methoxy group, an ethoxy group, or the like. Diazo compounds represented by the general formula (III) (IV) (V) can be prepared by the following method. First, a phenol or a phenol derivative reacts with a diketone in the presence of an amine to form a diketone, and a tosyl azide is added to the diketone to change the diketone to a diazo compound. In particular, the diazo compound of formula (III) may be one of those shown in Table 4, the diazo compound of formula (IV) is one of those shown in Table 5, and the diazo compound of formula (V) is shown in Table 6 It may be one of those shown in.

The alkali soluble resin to be used in the second photosensitive composition according to the present invention may be the same as that used in the first photosensitive composition.

기로 표시되는 1-4기를 가진 지방족 화합물 또는 아리사이클릭 화합물을 포함한다. 감광제는 다음과 같이 제조될 수 있다. 우선 알콜이 아민존재하에 디케톤과 반응하여 디케톤이 된후 디케톤에 토실 아지등의 가해져서 디케톤 디아조 화합물로 바꾸며 이 디아조 화합물은 표7에 나타낸 것들중 하나이다.In the third photosensitive composition according to the present invention, the third photosensitive composition has 4-12 carbon atoms as a photosensitizer.

Aliphatic compounds or acyclic compounds having 1-4 groups represented by the group. Photosensitizers can be prepared as follows. The alcohol first reacts with the diketone in the presence of an amine to form a diketone, and then adds dicytone to a diketone to diketone diazo compound, which is one of those shown in Table 7.

The alkali soluble resin used in the photosensitive composition according to the present invention may be the same as that used in the first photosensitive composition. Preferably the second photosensitive composition or the third photosensitive composition comprises 1-100 parts by weight of the photosensitizer and 100 parts by weight of alkali-soluble resin.

If the composition contains less than part by weight of photosensitizer, the photosensitivity is insufficient, and the resin contained in that portion of the exposed composition layer may not be sufficiently dissolved in the developer, while if the composition contains more than 100 parts by weight of the photosensitizer When the composition coats the substrate or the like, some of the photosensitizer crystallizes, making smooth coating impossible.

Certain photosensitive compositions according to the present invention may include sensitizers, dyes, surfactants and / or polymers, if desired, in addition to alkali-soluble resins and photosensitizers. Polymers that improve the quality of the composition layer include, for example, epoxy resins, polymethyl methacrylic acid, ethylene oxide-propylene oxide copolymers, polystyrenes, silicone rubbers, and the like.

A method of forming a photoresist pattern from a photoresist comprising the photosensitive composition according to the present invention is described below. First, the photosensitive composition is dissolved in an organic solvent to form a resist solution. Suitable organic solvents include ketone type solvents such as cyclohexanone, acetone, methyl ethyl ketone or methyl isobutyl ketone: cellosolve type solvents such as methyl cellosolve, methyl cellosolve acetate or ethyl cellosolve acetate; Solvents of ester type such as ethyl acetate, butyl acetate or isoamyl acetate; Or mixtures of two or more of the above solvents.

The resist solution prepared as described above is applied to a substrate by a known method such as spinning or dipping and then the resist solution applied to the substrate is dried at 150 ° C. or lower, preferably 70-120 ° C., to form a resist film. The substrate on which the resist film is formed may be a silicon substrate on which a silicon wafer, a blank mask insulating layer, or an electrically conductive layer is formed. The deep UV rays are irradiated onto the resist film through a mask having a desired pattern, and the deep UV rays are emitted from the KrF excimer laser and preferably have a wavelength of 248 nm.

The resist film exposed to deep UV rays is developed in an aqueous alkali solution to form a desired resist pattern.

Suitable aqueous alkali solutions include tetramethyl ammonium aqueous solution and the like.

Certain photosensitive compositions according to the invention exhibit high photosensitivity to deep UV rays, in particular to light having a wavelength of 248 nm emitted from KrF excimer lasers.

In general, the shorter the wavelength of light irradiated onto the resist film is, the clearer the generated resist pattern is.

The resolution the resist pattern can have when formed by the G-line exposure used so far is about 0.6 μm while the resist pattern by KrF excimer laser (248 nm) exposure of the resist film of the composition according to the invention is 0.3 μm. It can have a resolution of.

When the portion of the layer of the photosensitive composition of the present invention is exposed, the exposed layer portion is insoluble in the alkaline developer.

Therefore, the photoresist film made of the composition according to the present invention is of a negative type.

The silicon-containing photosensitive composition according to the present invention comprises a silicon-containing alkali-soluble resin and a photosensitive agent selected from the group consisting of: silicon-containing naphthoquinone diazide, silicon-containing azide and a compound represented by the following general formula (II): .

Wherein R ₁ -R ₄ is hydrogen, a substituted or unsubstituted alkyl group having 1-10 carbon atoms, a substituted or unsubstituted aryl group, or a substituted or unsubstituted silyl group.

Any of the resins shown in Table 1 may be used as the silicon-containing alkali-soluble resin.

Since the resin shown in Table 1 contains the phenol group and carboxyl group which show solid solubility in aqueous alkali solution, the resist film which consists of the silicone containing photosensitive composition in this invention can be developed to alkali, and these resins have high oxygen-resistant RIE.

The silicon containing naphthoquinonediazide and the silicon containing azide can be selected from those shown in Table 8.

Substituents of the substituted alkyl group used as R ₁ -R ₄ shown in formula (II) may be a halogen atom, an unsaturated group, a carbonyl group, a carboxyl group, a nitrile group, a thioether group, a thioester group, or the like.

The substituent of the substituted aryl or silyl group used as R ₁ -R ₄ in the general formula (II) may be a halogen atom, an unsaturated group, a carbonyl group, a carboxyl group, a nitrile group, a thioether group, a thioester group, an alkyl group, an alkoxy group, or the like. And the compound represented by formula (II) is shown in Table 9.

The silicone containing photosensitive composition of this invention contains 100 weight part of silicone containing alkali-soluble resin and 1-50 weight part of photosensitive agent.

If the composition contains less than 1 part by weight of a photosensitizer, the photosensitivity may be insufficient and the resin may not harden after the resin is exposed.

On the other hand, applicability | paintability worsens on the board | substrate etc. which a composition contains more than 50 weight part photosensitive agent.

The composition according to the present invention may include additives if necessary. Examples of the additives include UV absorbers, sensitizers, thermal polymerization inhibitors, antihalation agents, adhesion promoters, surfactants, and polymers.

The thermal polymerization inhibitor is used to maintain the composition without degradation of the composition for a long time, the anti-halation agent serves to prevent the halation from the substrate to which the composition is applied, the adhesion enhancer improves the adhesion between the substrate and the layer of the composition, the interface The active agent allows the layer of the composition to have a flat and smooth surface and the polymer improves the layer quality of the composition. Examples of such polymers include epoxy resins, polymethyl methacrylate resins, propylene oxide-ethylene oxide copolymers, and polystyrene. And silicone rubber polymers.

In order to use the silicon-containing photosensitive composition as the photoresist, it is first dissolved in a solvent to form a solution, and then the solution is applied directly to the substrate or to a flat layer formed on the substrate.

Suitable as the solvent are ketone type solvents such as cyclohexanone, acetone, methyl ethyl ketone or methyl isobutyl ketone; Cellosolve type solvents such as methyl cellosolve, methyl cellosolve acetate or ethyl cellosolve acetate; Solvents of ester type such as ethyl acetate, butyl acetate or isoamyl acetate; Or mixtures of two or more of these solvents.

In the following, how the silicon-containing photosensitive composition is coated with photoresist to form a photo-resist pattern is described.

First, a planarization layer is formed on a substrate, for example, a silicon substrate doped with an impurity in which a silicon oxide layer is formed, a substrate having a conductive layer formed of a silicon oxide layer and made of polycrystalline silicon.

In particular, the resin constituting the planarization layer is dissolved in a solvent, and the resulting solution is spin coated and dried, for example, on a substrate to form a planarization layer, which is a type capable of forming a thin film.

Solvents are, for example, toluene, xylene, ethyl cellosolve acetate, cyclohexane and the like.

An additive such as a diazo compound can be added to the resin solution for forming the planarization layer, and the resulting planarization layer can be easily heat cured.

This planarization layer is a commercially available photoresist consisting of a novolak resin and a naphthquinone diazide (OFPR-5000 manufactured by Toyo Kagawa Chemical Co., Ltd., ONPR-800HS and HPR-204, which is a trade name of Hunt). Is suitable.

The solution has a viscosity of 20-100 cps, preferably 60-100 cps because it is not easily spin coated when the viscosity is out of this range.

The planarization layer preferably has a thickness of 1-2 탆, preferably 1.5-2.0 탆, when the thickness is less than 1 탆, when the planarization layer is formed on the surface of the substrate, it has a flat surface and a stepped portion. On the other hand, if the thickness is larger than 2 mu m, the planarization layer tends to become an etching pattern having insufficient resolution.

The planarization layer may also be baked after drying, which is high enough to completely remove the solvent from the planarization layer and is performed at a temperature above the glass transition temperature of the resin forming the planarization layer, typically at a temperature of 50-250 ° C. For 0.5-120 minutes, preferably at 80-220 ° C. for 1-90 minutes.

A resist layer comprising a silicon-containing photosensitive composition is then formed in the planarization layer.

The composition is dissolved in the above-mentioned solvent to form a solution, which solution is applied to the planarization layer by a known method such as spin coating, and dried to form a resist layer, which solution is 10-100 cps, preferably 10-. It has a viscosity of 60 cps.

The thickness of the resist layer is 0.1-1.0 μm, preferably 0.2-0.6 μm, but if the thickness is less than 0.2 μm, the layer does not have adequate oxygen-resistant RIE and pinholes are easily formed in the film. Will be lowered.

The resist layer formed on the planarization layer is preferably baked to completely remove the solvent from the resist layer.

If the solvent remains in the resist layer, light irradiated to the layer is greatly dispersed in the layer, which inevitably lowers the resolution of the resulting resist pattern.

The resist layer is then exposed, that is to say that UV rays (wavelengths: 365 nm, 436 nm, 313 nm, 254 nm or 248 nm), electron beams or X-rays are irradiated to the resist layer through a mask having a predetermined pattern.

During the exposure the mask is placed in contact with or away from the resist layer.

The resist layer is then developed with an aqueous alkali solution. The exposed resist layer portion or the unexposed portion of the resist layer is dissolved and removed in an aqueous alkali solution to form a resist pattern.

The aqueous alkali solution is an organic alkali aqueous solution such as tetramethyl ammonium hydroxide aqueous solution or an inorganic alkaline aqueous solution such as aqueous ammonium solution, aqueous sodium hydroxide solution or aqueous potassium hydroxide solution.

The aqueous alkali solution is applied to the resist layer by various methods such as deposition or spraying.

The planarization layer then performs dry etching (oxygen RIE) by applying an oxygen plasma to the layer in which a resist pattern is used as a mask.

When the resist pattern is exposed to an oxygen plasma, a film of a material having a composition similar to that of silicon dioxide (SiO ₂ ) is formed on the surface of the resist pattern, and the film exhibits 10 to 100 times greater oxygen resistance RIE than the planarization layer.

Therefore, only the exposed portion of the planarization layer can be etched without damaging the resist pattern, and as a result, the resist pattern is transferred to the planarization layer to form a pattern layer.

Oxygen RIE is typically performed for 1-120 minutes at a power output of 0.01-10 W / cm 2, low pressure atmosphere (1 × 10 ⁻⁴ × −1 × 10 ⁻¹ torr).

The substrate is also etched using a pattern layer as a mask, which may be wet etching or dry etching, and dry etching is preferred when a fine pattern having a minimum stroke width of 3 μm or less is formed.

Finally, the remaining resin is removed from the substrate by adding a remover such as J-100 (manufactured by Nagase Kasei Co., Ltd.) to the substrate or applying an oxygen gas plasma to the substrate.

In this two-layer resist system, another additional step may be added to the process of transferring the pattern to the substrate, which further improves adhesion between the photosensitive layer and the planarization layer or between the planarization layer and the substrate; Baking treatment performed before and after the developing step; Re-exposure of UV rays performed before dry etching.

As described above, the photosensitive compositions according to the present invention have high oxygen resistance RIE and can be developed in an alkaline liquid.

Since the upper layer must have sufficient photosensitivity and oxygen RIE resistance, the composition of the present invention can be suitably used as an upper layer material in a two layer resist system.

In addition, since the organic solvent does not need to be used to develop the composition layer, there is no fear that the resin contained in the composition will expand.

The use of the composition according to the invention is not limited to two layer resist systems but can also be used in single layer resist systems.

The present invention will be described in more detail with reference to the following examples.

[Example 1-11]

The alkali-soluble resin shown in Table 10 and the photosensitive agent shown in Table 11 were mixed at the ratio shown in Table 12, the mixture was dissolved in ethyl cellosolve acetate, and eleven photosensitive compositions were prepared, using this solution as follows. Formed.

The solution was first spin coated onto a single crystal silicon wafer and the coated solution was dried to form a 1.2 μm thick resist film.

A raw UV ray having a wavelength of 248 nm emitted from the excimer laser was then exposed to the resist film at the exposure dose shown in Table 13 using a stepper having a numerical number (NA) of 0.35.

The resist film exposed to an aqueous tetramethyl ammonium hydroxide (TMA H) solution with the concentrations shown in Table 13 was then developed for the time shown in Table 13 to form a resist pattern.

Eleven resist patterns were made as described above, and their resolution (width of line and space) was observed with an electron microscope, and the results are shown in FIG.

As can be seen from Table 13, the composition according to the present invention exhibited sufficient photosensitivity to light having a wavelength of 248 nm, and as can be seen from Table 13, a resist pattern made of this composition, that is, the resist patterns of Examples 1 to 11 High resolution is shown.

Example 12-20

The alkali-soluble resin shown in Table 14 and the photosensitive agent shown in Table 15 were mixed at the ratio shown in Table 16, and the mixture was dissolved in ethyl cellosolve acetate to form nine photosensitive compositions, and each solution was formed as follows to form a resist pattern. .

First, a novolak-type resist (ie, ONPR-800HS, manufactured by Toko Oyo Chemical Co., Ltd.) was applied to a silicon substrate, and the resist was dried and heat-treated at 200 ° C. for 15 minutes to form a flattening layer having a thickness of 2.0 μm. .

The solution was then spin coated onto a planarization layer and dried to form a resist film with a thickness of 0.6 mu m.

Further, a raw UV ray having a wavelength of 248 nm emitted from the excimer laser was exposed to the resist film at the exposure dose shown in Table 17 using a stepper having a NA of 0.35, and then the exposed resist film was exposed to the TMAH aqueous solution having the concentration shown in Table 17 for 40 seconds. The development treatment was performed to form an upper resist pattern.

A silicon substrate with a resist pattern formed of a dry etching apparatus that is, the Tokugawa by Seisakusho whether or sikki manufactured product HiRRIE added to the oxygen plasma on the silicon substrate in an oxygen output 0.06W / ㎠, a low-pressure atmosphere (2 × 10 ^-2 toor) RIE Let

The upper resist pattern is transferred to the planarization layer (that is, the lower layer) by this oxygen RIE.

Thus, nine two-layer resist patterns were formed, and the resolution and oxygen-resistant RIE resistance of the upper layer pattern of this two-layer resist pattern were measured with an electron microscope, and the results are shown in Table 17.

As can be clearly seen from Table 17, the upper resist pattern made of this composition, that is, of Example 12-20, showed several times higher oxygen RIE resistance than the planarization layer in terms of high resolution and etching degree.

Comparative Example 1

Alkali-soluble resins 14-4 shown in Table 14 and photosensitive agents 15-6 shown in Table 15 were mixed in the proportions shown in Table 16, and the mixture was dissolved in ethyl cellosolve acetate to prepare a photosensitive composition, and the solution was used in the examples. A two layer resist pattern was formed in the same manner as in 12-20.

The resist pattern of Comparative Example 1 was observed with an electron microscope, and the resolution and the oxygen resistance of the upper layer pattern of the two-layer resist pattern were measured, and the results are shown in Table 17.

As can be seen from this table, the upper layer pattern of Comparative Example 1 showed high resolution and relatively high oxygen resistance RIE.

However, unlike the upper layer pattern of Example 12-20, in which the upper layer pattern was used to form a rectangular hole and transfer the original pattern to the planarization layer, the upper pattern had a triangle hole and could not transfer the pattern faithful to the original pattern to the planarization layer. .

Example 21-25

Five mixtures were prepared by mixing alkali-soluble resins and photosensitizers (both shown in Table 18) in the proportions shown in Table 18, and passing the mixture through a 0.2 μm mesh filter to prepare five photosensitive compositions.

Each photosensitive composition was spin coated onto a single crystal silicon wafer and the coated solution was dried at 80 ° C. to form a resist film having a thickness of 0.8 μm.

Then, a raw UV ray having a wavelength of 248 nm emitted from the excimer laser was exposed to the resist film by a stepper, and the exposed resist film was immersed in a TMAH aqueous solution whose concentration is shown in Table 19 for 30 seconds, followed by developing and washing the film with water. A resist pattern was formed.

In this way, five resist patterns were formed and observed in an electron microscope to measure the resolution (width of lines and spaces), the thickness reduction due to their shape and shape treatment, and are shown in Table 19.

Comparative Example 2

The alkali-soluble resin and the photosensitive agent shown in the last column of Table 18 were mixed at the ratios shown in Table 18, and the mixture was dissolved in cellosolve acetate to prepare a photosensitive composition, and the solution was treated as in Examples 21-25 to obtain a resist pattern. Formed.

The resist pattern was observed under an electron microscope to measure the decrease in resolution (width of lines and spaces), shape and thickness thereof, and the results are shown in Table 19.

As can be seen from Table 19, the resist pattern of Example 21-25 prepared from a composition comprising an alkali soluble resin and having a transmittance of 50% or more in light having a wavelength of 248 nm when in the form of a 1.0 탆 film was sufficiently small. It had a width of line and space and only resulted in a minimum thickness reduction.

On the other hand, the resist pattern of Comparative Example 2, which was prepared from a composition comprising an alkali soluble resin and had a transmittance of less than 50% to the light when in the form of a 1.0 μm film, did not have a sufficiently small width of line and space, and the resist The opening of the pattern had triangular holes and the pattern of Comparative Example 2 experienced a 50% substantial thickness reduction.

Example 26-27

Twelve photosensitive compositions were prepared by mixing the alkali-soluble resins shown in Table 10 and the photosensitizers shown in Table 20 in the proportions shown in Table 21 and dissolving the mixture in 250 g of ethyl cellosolve acetate.

This solution was spin coated onto a single crystal silicon wafer, the coated solution was dried for 5 minutes, and the wafer was left on a hot plate heated to 70 ° C. to form a resist film having a thickness of 1.0 μm.

A raw UV ray having a wavelength of 248 nm emitted from the excimer laser was then exposed to the resist film under the conditions shown in Table 22 by a stepper having an NA of 0.35, and then the exposed film was dissolved in a TMAH aqueous solution whose concentration is shown in Table 22. The development process was carried out for the time shown in 22 to form a resist pattern.

12 resist patterns were formed as mentioned above, and the resolution (width of a line and a space) was measured with the electron microscope.

The resolution is shown in Table 22 in the size of lines and spaces that can be formed using the photosensitive composition.

As can be seen from Table 22, the composition according to the present invention exhibited sufficient sensitivity to light of 248 nm and, as can be clearly seen from Table 22, the resist pattern made from this composition, i.e., the compositions of Examples 26-37, had a high resolution. Had

Example 38-51

The silicon-containing alkali-soluble resin shown in Table 23 and the photosensitive agent shown in Table 24 were mixed at the ratio shown in Table 25, and the mixture was dissolved in ethyl cellosolve acetate so that each composition had a concentration of 20% to prepare 14 photosensitive compositions. Using the respective solutions to form a resist pattern in the following procedure.

First, a novolak-type resist (ie, ONPR-800HS, manufactured by Toko Oyo Chemical Co., Ltd.) was coated on a silicon substrate, and the resist was dried and heat-treated at 200 ° C. for 15 minutes to form a 2.0 μm thick flattening layer.

The solution was then coated on a planarization layer and dried to form a resist film with a thickness of 0.6 μm.

In addition, UV rays having a specific wavelength shown in Table 26 were exposed to the resist film at the exposure amounts shown in Table 26 using a stepper having a NA of 0.35.

The exposed resist film was then developed in a TMAH aqueous solution whose concentration is shown in Table 26 for 40 seconds to form an upper resist pattern.

Oxygen RIE treatment at low pressure atmosphere (2 × 10 ^-2 torr) at 0.6W / m2 by applying an oxygen plasma to the silicon substrate by using a dry etching apparatus, HiRRIE, manufactured by Tokuda Seisakusho Co., Ltd. Was done.

The upper layer resist pattern was transferred to the planarization layer (that is, the lower layer) by this oxygen RIE to produce 14 two-layer resist patterns.

Comparative Examples 3 and 4

The mixture was prepared by mixing the alkali-soluble resin 23-2 shown in Table 23 and the photosensitive agent 24-8 shown in Table 24 at the ratio shown in Table 25, and the alkali-soluble resin 23-3 shown in Table 23 and the photosensitive agent shown in Table 24 as well. A mixture was prepared by mixing 24-9 in the proportions shown in Table 5.

This mixture was dissolved in ethyl cellosolve to make two photosensitive compositions.

Using the composition, two two-layer resist patterns were formed in the same manner as in Examples 38-51.

Fourteen two-layer resist patterns formed in Examples 38-51 were observed with an electron microscope to measure the resolution and oxygen resistance RIE of these two-layer resist patterns.

In addition, the two two-layer resist patterns of Comparative Examples 3 and 4 were observed with an electron microscope, and the resolution and oxygen-resistant RIE of the upper layer patterns of these two-layer resist patterns were measured, and the results are shown in Table 26.

As can be seen from Table 26, the two-layer resist pattern prepared from the composition of the present invention of Examples 38-51 had a high resolution and their upper pattern was 10-15 times larger in oxygen resistance than the planarization layer in terms of etching degree. RIE was shown.

As can be seen from Table 26, although the upper layer pattern had high oxygen resistance RIE, the resist patterns of Comparative Examples 3 and 4 showed lower resolution than the resist patterns of Examples 38-51.

In addition, since the upper layer patterns of Comparative Examples 3 and 4 had a triangular hole, the pattern faithful to the original pattern could not be transferred to the planarization layer, unlike the upper layer pattern of Examples 38-51 having a rectangular hole.

TABLE 1

Claims (20)

The photosensitive composition containing alkali-soluble resin and the photosensitive agent represented by general formula (I).

Wherein R ₁ and R ₂ are an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms, an unsubstituted or substituted alkoxy group having 1 to 20 carbon atoms, an unsubstituted or substituted aryl group, an unsubstituted or substituted aryloxy group Or an unsubstituted or substituted analino group. The photosensitive composition of claim 1, wherein R ₁ or R ₂ or both R ₁ and R ₂ contain silicone. The photosensitive composition according to claim 1, wherein the alkali-soluble resin is an allyl group having a hydroxyl group or a polymer containing a carboxyl group. The photosensitive composition according to claim 1, wherein the alkali-soluble resin is a resin having a transmittance of 50% or more to light having a wavelength of 248 nm when formed into a film having a thickness of 1.0 mu m. The polyvinylphenol having a silicone-containing alkyl group introduced into a novolak resin, polyisopropenyl, polyvinylphenol, benzene ring or hydroxy group, and vinyl phenol monomer and styrene, acrylic A photosensitive composition, characterized in that the copolymer with a compound selected from the group consisting of ronitrile, methyl methacrylate, methacrylate. The photosensitive composition as claimed in claim 1, comprising 100 parts by weight of the alkali-soluble resin and 1-100 parts by weight of the photosensitive agent. Directly bonded to alkali-soluble resins and benzene rings

A photosensitive composition comprising a aromatic compound having a group and used as a photosensitizer. 8. The photosensitive composition as claimed in claim 7, wherein the alkali-soluble resin is a polymer containing an aryl group or a carboxyl group having a hydroxyl group. 8. The photosensitive composition as claimed in claim 7, wherein the alkali-soluble resin is a resin having a transmittance of 50% or more to light when formed into a film having a thickness of 1.0 mu m. 8. The polyvinylphenol of claim 7, wherein the alkali-soluble resin comprises a silicone compound having a silicone-containing alkyl group introduced into a novolak resin, poly isopropenylphenol, polyvinylphenol, benzene ring or a hydroxy group, and A photosensitive composition comprising a copolymer of a vinylphenol monomer with a compound selected from styrene, acrylonitrile, methylmethacrylate, and methacrylate. A photosensitive composition according to claim 7, wherein the photosensitive composition comprises at least one compound represented by the following general formula (III) (IV) (V).

Wherein R is hydrogen, an unsubstituted or substituted alkyl group having 1-10 carbon atoms, m is an integer ranging from 1-6, 1 and n are integers ranging from 0-5, with the proviso that 1 + m + n = 6.

Wherein R is hydrogen, an unsubstituted or substituted alkyl group having 1-10 carbon atoms: 1,1 ', m, m', n and n 'are integers in the range 0-5, provided that 1 + m + n = 1 '+ m' + n '= 5, m + m'

0.

Wherein R is hydrogen, an unsubstituted or substituted alkyl group having 1-10 carbon atoms, m is an integer ranging from 1-5, and 1 and m are integers ranging from 0-4, provided that 1 + m + n = 5 . 8. A photosensitive composition according to claim 7, comprising 100 parts by weight of said alkali-soluble resin and 1-100 parts by weight of said photosensitizer. Alkali-soluble resin, 4-12 carbon atoms

A photosensitive composition comprising an aliphatic compound or an arcyclic compound having 1 to 4 groups represented by the above and used as a photosensitizer. The photosensitive composition as claimed in claim 13, wherein the alkali-soluble resin is a polymer containing an aryl group or a carboxyl group having a hydroxyl group. The photosensitive composition as claimed in claim 13, wherein the alkali-soluble resin is a resin having a transmittance of 50% or more to light having a wavelength of 248 nm when it is in the form of a film having a thickness of 1.0 mu m. 14. The polyvinylphenol and vinylphenol according to claim 13, wherein the alkali-soluble resin comprises a silicone compound having a silicone-containing alkyl group introduced into a novolak resin, polyisopropenyl, polyvinylphenol, benzene ring or a hydroxy group. A photosensitive composition comprising a monomer and a copolymer of a compound selected from the group consisting of styrene, acrylonitrile, methyl methacrylate and methacrylate. The photosensitive composition as claimed in claim 13, comprising 100 parts by weight of the alkali-soluble resin and 1-100 parts by weight of the photosensitizer. Silicone-containing alkali-soluble resins; A silicon-containing photosensitive composition comprising a photosensitive agent selected from the group consisting of a silicon-containing naphtho quinonediazide, a silicon-containing azide and a compound represented by the following general formula (II).

(Ⅱ) Wherein R ₁ -R ₄ is hydrogen, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group, or a substituted or unsubstituted silyl group. The photosensitive composition as claimed in claim 18, wherein the alkali-soluble resin includes an aryl group or a carboxyl group having a hydroxyl group. 19. A photosensitive composition according to claim 18, comprising 100 parts by weight of said alkali-soluble resin and 1-50 parts by weight of a photosensitizer.