KR100570948B1 - Positive photoresist composition for manufacturing lcd and method for forming resist pattern - Google Patents

Abstract

Even under low NA conditions, a resist pattern can be formed with high resolution, and a resist material for manufacturing an LCD with good linearity is preferably provided. This resist material is (A) alkali-soluble resin,

(B) an esterification reaction product having an average esterification rate of 30 to 90% between a low molecular weight novolak resin having a polystyrene-reduced mass average molecular weight of 300 to 1300 and a naphthoquinone diazide sulfonic acid compound,

(C) phenolic hydroxyl group containing compound of molecular weight 1000 or less,

(D) an organic solvent,

It is a positive photoresist composition for LCD manufacture containing a.

Alkali-Soluble Resin, Polystyrene, Positive Photoresist

Description

Formation method of positive photoresist composition and resist pattern for manufacturing LCD {POSITIVE PHOTORESIST COMPOSITION FOR MANUFACTURING LCD AND METHOD FOR FORMING RESIST PATTERN}

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an explanatory diagram for applying a positive photoresist composition to a glass substrate, baking and drying to expose the pattern, and then containing the developer from the substrate X to Z in a developing apparatus having a slit coater.

The present invention relates to a method of forming a positive photoresist composition and a resist pattern for LCD production.

In the manufacture of liquid crystal display devices (LCDs), which form liquid crystal display portions on glass substrates up to now, the manufacture of semiconductor devices in view of relatively low cost and the ability to form resist patterns excellent in sensitivity, resolution and shape. The positive type photoresist material which consists of a system of the novolak resin-quinonediazide group containing compound used for is used widely.

However, for example, in the manufacture of semiconductor devices, disc-shaped silicon wafers with a maximum diameter of 8 inches (about 200 mm) to 12 inches (about 300 mm) are used, whereas in the manufacture of LCDs, at least 360 mm x 460 mm Rectangular glass substrates are used.

As described above, in the field of LCD manufacturing, the substrate to which the resist material is applied differs in terms of material and shape, but differs greatly from that used in the manufacture of semiconductor devices in terms of size.

Therefore, it is required for the resist material for LCD manufacture to be able to form the resist pattern with favorable characteristics, such as shape and dimensional stability, with respect to a wide substrate surface whole surface.

In addition, since a very large amount of resist material is consumed in the manufacture of LCD, it is desired to have a low cost in addition to the above-described characteristics in the resist material for producing LCD.

There are many reports as a resist material for LCD manufacture until now (for example, following patent documents 1-6). The resist materials described in Patent Literatures 1 to 6 are inexpensive, and for example, a resist pattern excellent in coating properties, sensitivity, resolution, shape and dimensional stability can be formed on a small substrate of about 360 mm × 460 mm. Therefore, it can use suitably for the purpose of manufacturing a comparatively small LCD.

[Patent Document 1]

Japanese Patent Laid-Open No. 9-160231

[Patent Document 2]

Japanese Patent Laid-Open No. 9-211855

[Patent Document 3]

Japanese Unexamined Patent Publication No. 2000-112120

[Patent Document 4]

Japanese Unexamined Patent Publication No. 2000-131835

[Patent Document 5]

Japanese Laid-Open Patent Publication 2000-181055

[Patent Document 6]

Japanese Laid-Open Patent Publication 2001-75272

However, in recent years, the demand for large-sized LCDs is increasing than in the past due to the increase in the size of PC displays or the spread of liquid crystal TVs. In addition, the lower cost of the LCD is also required, and therefore, the improvement of the manufacturing efficiency of the LCD is required.

Therefore, in the LCD manufacturing field, a resist material having a sensitivity of about 30 to 50 mJ has been desired in view of improvement in throughput (processing amount per unit time) and process controllability. In addition, from the viewpoint of improving throughput (amount of processing per unit time), it is desired to make the exposure area as wide as possible, at least about 100 mm 2, and in general, LCD manufacture has an NA (a numerical aperture of a lens) of, for example, 0.3 or less, especially It is known to use an exposure process with low NA conditions of 0.2 or less.

However, in the case of using a low NA exposure process, it was difficult to form a resist pattern having excellent shape at a high resolution, for example, under a low NA condition of 0.3 or less, as a resist material for producing a conventional LCD.

In other words, typically resolution (resolution limit) is Rayleigh's equation:

R = k ₁ × λ / NA

Where R is the resolution limit, k ₁ is the proportionality constant determined by the resist, process or image forming method, λ is the wavelength of light used in the exposure process, and NA is the numerical aperture of the lens. The resolution can be increased by using a short light source of or using a high NA exposure process. For example, the resolution can be increased by using photolithography technology using a shorter wavelength i-ray (365 nm) exposure, instead of g-ray (436 nm) exposure that has been used in the manufacture of conventional LCDs.

However, in manufacture of LCD, as mentioned above, high NA which becomes narrow an exposure area is not desirable, and it is desired to use the exposure process in low NA conditions. Therefore, it was difficult to obtain high resolution.

Currently, next-generation LCD is a high-performance LCD called a "system LCD" in which integrated circuit parts such as a driver, a digital-to-analog converter (DAC), an image processor, a video controller, and a RAM are formed simultaneously with a display part on one glass substrate. Technological development is being actively carried out (Semiconductor FPD World 2001.9, pp.50-67).

In this case, since the integrated circuit portion is also formed on the substrate in addition to the display portion, the substrate tends to be larger in size. Thus, exposure at lower NA conditions is more desirable than in conventional LCD manufacturing.

In addition, in such a system LCD, the pattern size of the display portion is, for example, about 2 to 10 µm, whereas the integrated circuit portion is formed in a fine dimension on the order of 0.5 to 2.0 µm. Therefore, it is desirable to be able to form a fine resist pattern on the order of 0.5 to 2.0 mu m, and a resist material having a higher resolution than that of a conventional LCD material resist is desired.

However, as mentioned above, since the resist material for manufacturing a conventional LCD is difficult to form at high resolution under low NA conditions, it is difficult to use it for the manufacture of a system LCD. For example, under low NA conditions of 0.3 or less, formation of a fine resist pattern excellent in shape, for example, 2.0 μm or less, is difficult, and the resulting resist pattern tends to have a tapered shape instead of a rectangle.

Specifically, JP 2001-75272 A discloses a liquid crystal resist containing an alkali-soluble resin and a photosensitive component and not containing a sensitizer.

However, this liquid crystal resist had problems such as being unsuitable for i-ray exposure and the difficulty of forming a resist pattern of 2.0 mu m or less required for the manufacture of a system LCD.

Therefore, in the manufacturing process of the system LCD, a resist material suitable for i-ray exposure and capable of forming a fine resist pattern excellent in shape even under low NA conditions of 0.3 or less, for example, has been desired.                         

That is, the present invention has a sensitivity of about 30 to 50mJ, is excellent in resolution under low NA conditions, and is a positive type photoresist composition as a resist material suitable for manufacturing an LCD in which an integrated circuit and a liquid crystal display portion are formed on one substrate. Another object is to provide a method of forming a resist pattern.

In order to solve the said subject, the positive photoresist composition for LCDs of this invention,

(A) alkali-soluble resin,

(B) an esterification reaction product having an average esterification rate of 30 to 90% between a low molecular weight novolak resin having a polystyrene-reduced mass average molecular weight of 300 to 1300 and a naphthoquinone diazide sulfonic acid compound,

(C) a phenolic hydroxyl group containing compound whose molecular weight is 1000 or less,

(D) organic solvent

It is characterized by containing.

This positive photoresist composition for LCD is suitable as a positive photoresist composition for LCD for i-ray exposure processes.

Moreover, it is suitable as a positive photoresist composition for LCD for exposure processes whose NA is 0.3 or less.

Moreover, it is suitable as a positive photoresist composition for LCD for LCD manufacture in which an integrated circuit and a liquid crystal display part were formed on one board | substrate.

In the description of the present invention, in the case of a system LCD, this " LCD having an integrated circuit and a liquid crystal display portion formed on one substrate "

In addition, the method of forming the resist pattern of the present invention,

(1) applying the positive photoresist composition of the present invention on a substrate and forming a coating film,

(2) heat-treating (prebaking) the substrate on which the coating film is formed and forming a resist film on the substrate;

(3) performing selective exposure using a mask having a mask pattern drawn on the resist film;

(4) performing a heat treatment (post exposure bake) on the resist film after the selective exposure;

(5) a step of developing the resist film after the heat treatment using an aqueous alkali solution to form a resist pattern on the substrate;

(6) a rinsing step of washing away the developer remaining on the resist pattern surface.

In the step (3) of performing selective exposure, a mask in which both a resist pattern forming mask pattern of 2.0 µm or less and a mask pattern for forming resist pattern of more than 2.0 µm is drawn is used as the mask. 5) In the step of simultaneously forming a resist pattern, a resist pattern for integrated circuits having a pattern dimension of 2.0 μm or less and a resist pattern for liquid crystal display portions larger than 2.0 μm may be simultaneously formed on the substrate.

Embodiment of the invention

[Positive Photoresist Composition for LCD]

<(A) component>

(A) component is alkali-soluble resin.

(A) component is not restrict | limited in particular, It can select arbitrarily 1 type (s) or 2 or more types from what can be normally used as a film formation material in positive type photoresist composition.

For example, phenols (phenol, m-cresol, p-cresol, xyleneol, trimethylphenol, etc.) and aldehydes (formaldehyde, formaldehyde precursor, propionaldehyde, 2-hydroxybenzaldehyde, 3-hydroxybenzaldehyde, 4 -Novolak resin obtained by condensing hydroxybenzaldehyde and the like) and / or ketones (methyl ethyl ketone, acetone and the like) in the presence of an acidic catalyst;

Hydroxystyrene resins such as homopolymers of hydroxystyrene, copolymers of hydroxystyrene with other styrene monomers, copolymers of hydroxystyrene with acrylic acid or methacrylic acid or derivatives thereof;

Acrylic acid or methacrylic acid resin which is a copolymer of acrylic acid or methacrylic acid and its derivative (s) is mentioned.

In particular, the novolak resin obtained by condensation reaction of phenols containing m-cresol and p-cresol with aldehydes containing formaldehyde is suitable for adjusting a resist material having high sensitivity and excellent resolution.

(A) component can be manufactured according to a conventional method.

Although the polystyrene reduced mass mean molecular weight by gel permeation chromatography of (A) component changes with the kind, it is 2000-100000 from a viewpoint of a sensitivity and pattern formation, Preferably it is 3000-20000.

<(B) component>

The component (B) is an ester having an average esterification rate of 30 to 90% of a low molecular weight novolak resin and a naphthoquinone diazide sulfonic acid compound having a polystyrene equivalent mass average molecular weight (hereinafter abbreviated as Mw) of 300 to 1300. As the reaction reaction product, one or two or more kinds belonging to these esterification reaction products can be selected and used. The polystyrene reduced mass average molecular weight is measured by GPC, for example.

As the low molecular weight novolak resin, for example, the alkali average soluble novolac resin used in the above-mentioned component (A) can be used by adjusting the mass average molecular weight in the above range.

Preferably Mw of this low molecular weight novolak resin is 300-1300, a lower limit becomes 350 or more, and an upper limit becomes preferably 700 or less.

By setting the mass average molecular weight in this range, it is possible to provide a resist material which is highly sensitive, has excellent resolution, and is suitable for an i-ray exposure process under low NA conditions.

In order to adjust mass average molecular weight to the said range, the following three means are mentioned, for example.

(i) Low molecular weight using a known fractionation operation for separating a low molecular weight region and a high molecular weight region of a novolak resin having a Mw of about 2000 to 30000 obtained by condensation reaction of desired phenols with aldehydes and / or ketones. It can be obtained by taking the region part.

In the synthesis of the alkali-soluble novolak resin of component (A), it is common knowledge that a fractionation operation is used to selectively take a high molecular weight region, and a fractionation operation for obtaining this low molecular weight novolak resin is also a subject to be selectively taken. The same operation can be applied except that the low molecular weight region is different.

(ii) In the condensation reaction of desired phenols with aldehydes and / or ketones, Mw of condensates in the reaction solution can be measured in order during the reaction, and can be obtained by terminating the reaction when Mw is in the range of 300 to 1300. .

If the various raw materials used in the synthesis, the type or amount and ratio of the catalysts, and the reaction conditions (solution concentration, reaction temperature, mixing means of various raw materials, etc.) are the same, once the Mw in the reaction is measured, the same low molecular weight When synthesize | combining novolak resin, the thing of desired Mw can be obtained only by controlling reaction time.

(iii) condensation reaction of the desired phenols with aldehydes and / or ketones in the presence of an acidic catalyst or a basic catalyst to synthesize 2 to 4 nucleated low molecular phenolic compounds or dimetholol thereof (referred to as "phenol A"). In addition, it can obtain by making a methol group containing phenol or phenols which do not contain a metirol group react with this (this is called "phenol B").

It is necessary to control reaction of phenol A and phenol B so that Mw may be in the range of 300-1300, and it can carry out by controlling the reaction time mentioned above, for example.

In addition, the control can be easily performed by adding a very small amount of a low concentration solution containing phenol B to a high concentration solution containing phenol A.

In addition, the ratio of phenols, aldehydes and / or ketones can be appropriately adjusted according to the difference between the target compound and the synthetic means, for example, 1: 1 to 2: 1 (molar ratio).

As (B) component, it is especially preferable to contain 1 or more types of the following two types ((i), (ii)) from an effect point.

(i) Synthesized using only bifunctional phenolic compounds as phenols and using aldehydes and / or ketones (preferably formaldehyde only) as condensing agents.

(ii) Synthesis using only difunctional phenol compounds and monofunctional phenol compounds as phenols, and using aldehydes and / or ketones (preferably formaldehyde only) as condensing agents.

The said "functional group" means the number of hydrogen atoms (this hydrogen atom reacts with aldehydes and / or ketones) present in the reaction site (2, 4, 6 positions) with aldehydes and / or ketones of phenols.

The bifunctional phenolic compound is represented by the following formula (1).

(Wherein R ¹ to R ⁵ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, two of R ¹ , R ³ and R ⁵ are hydrogen atoms, and one is an alkyl group having 1 to 5 carbon atoms) to be.)

In the bifunctional phenolic compound, the alkyl group having 1 to 5 carbon atoms (preferably 1 to 3, more preferably a methyl group) may be linear or branched.

In addition, there is no superiority at the position where the alkyl group couple | bonds among R <^1> , R <^3> and R <^5> .

As the bifunctional phenolic compound, o-cresol, p-cresol, 2,5-xylenol, 3,4-xylenol, 2,3,5-trimethylphenol are preferable because of low cost and excellent properties.

The said monofunctional phenolic compound is represented by following General formula (2).

Wherein R ¹¹ to R ¹⁵ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, one of R ¹¹ , R ¹³ and R ¹⁵ is a hydrogen atom, and two are hydrogen atoms of 1 to 5 carbon atoms. Alkyl group.)

In the monofunctional phenolic compound, the alkyl group having 1 to 5 carbon atoms (preferably 1 to 3, more preferably a methyl group) may be linear or branched.

In addition, there is no superior position at the position where the alkyl group couple | bonds among R <^11> , R <^13> and R <^15> .

As a monofunctional phenolic compound, 2, 4- xylenol and 2, 6- xylenol are preferable at the point of being inexpensive and excellent in characteristic.

In the above (i), bifunctional phenolic compounds: aldehydes and / or ketones (preferably formaldehyde) are used in a ratio of 1: 1 to 2: 1 (molar ratio) in that they are excellent in properties.

In the above (ii), since the bifunctional phenolic compound: monofunctional phenolic compound is excellent in a characteristic, it is used in 10: 1-1:10, Preferably it is 5: 1-1: 5 (molar ratio). The sum of phenols: aldehydes and / or ketones (preferably formaldehydes) are used in a ratio of 1: 1 to 2: 1 (molar ratio) in terms of excellent properties.

As a method for synthesizing the low molecular weight novolak resin of the above (ii), (1) A solution of a monofunctional phenol compound is blended with a dimetholol solution of a bifunctional phenol compound obtained by a conventional method, and condensation reaction is carried out in the presence of an acid catalyst. And a method of conducting a condensation reaction in the presence of an acid catalyst by blending a solution of a monofunctional phenol compound to a condensation reaction product of a bifunctional phenol compound with aldehydes and / or ketones.

① is suitable for the synthesis of low molecular weight novolac resins containing 3 or less benzene rings, and ② is suitable for the synthesis of low molecular weight novolac resins containing 4 or more benzene rings.

Subsequently, the esterification reaction of this low molecular weight novolak resin and a naphthoquinone diazide sulfonic acid compound is performed, and the esterification product [component (B)] whose average esterification rate is 30 to 90% is obtained.

The naphthoquinone diazide sulfonic acid compound can be used arbitrarily by selecting 1 type or 2 types or more from what is generally used in positive type photoresist composition.

There is no restriction | limiting in particular about the method of esterification reaction, Conventionally well-known reaction can be used.

For example, naphthoquinone diazidesulfonyl chloride is condensed with a low molecular weight novolak resin. Specifically, naphthoquinone-1,2-diazide-4 (or 5) -sulfonyl chloride and a low molecular weight novolak resin are used as dioxane, n-methylpyrrolidone, dimethylacetamide, tetrahydrofuran and the like. A predetermined amount is dissolved in an organic solvent of, and a basic catalyst such as triethylamine, triethanolamine, pyridine, alkali carbonate, alkali hydrogen carbonate and the like is added to the reaction to wash and dry the product.

The average esterification rate of the esterification product thus obtained is 30 to 90%, preferably about 40 to 70%. By setting it as 30% or more, the resist pattern excellent in contrast can be formed. On the other hand, the fall of sensitivity can be prevented by setting it as 90% or less. When it exceeds 90%, a remarkable sensitivity fall may occur, and the positive resist composition for LCD may be unsuitable for system LCD.

The esterification rate can be adjusted by changing the quantitative ratio of the low molecular weight novolak resin and the naphthoquinone diazide sulfonic acid compound, the reaction time of the esterification reaction, and the like.

In addition, the ratio of a low molecular weight novolak resin and a naphthoquinone diazide sulfonic-acid compound is 0.3-0.9 mol of a naphthoquinone diazide sulfonic-acid compound with respect to 1 mol of hydroxyl groups in a low molecular weight novolak resin from the point of adjustment of an esterification rate, etc. Preferably it is 0.4-0.7 mol.

This (B) component is what is called a photosensitive component.

In addition to this (B) component, the other naphthoquinone diazide ester compound generally used in the positive photoresist composition can also be used for the positive photoresist composition of this invention.

For example, an esterification reaction product of a phenol compound such as polyhydroxybenzophenone or alkyl gallate and a naphthoquinone diazide sulfonic acid compound may be used.

However, it is preferable that the usage-amount is 50 mass% or less, especially 20 mass% or less in all the photosensitive components containing (B) component in the point which does not impair the effect of this invention.

In positive type photoresist composition, the total compounding quantity of the photosensitive component containing (B) component is 10-70 mass% with respect to the total amount of alkali-soluble resin which is (A) component, and the following (C) component, Preferably it is 20 It is preferable to select in the range of -60 mass%.

And the compounding quantity of (B) component in the photosensitive component is more than 50 mass%, Preferably it becomes 80-100 mass%.

By making the compounding quantity of (B) component more than a lower limit, the image faithful to a pattern can be obtained and transferability can also be improved. When the compounding quantity of (B) component is below an upper limit, sensitivity deterioration can be suppressed, and the homogeneity of the resist film formed from a positive photoresist composition can be improved, and resolution can be improved.

<(C) component>

The component (C) is preferably a non-benzophenone-based phenolic hydroxyl group-containing compound. By using this (C) component, the material which is excellent in a sensitivity improvement effect, and is highly sensitive and high resolution also in the i-ray exposure process in low NA conditions is obtained.

The molecular weight of component (C) is preferably 1000 or less, preferably 700 or less, substantially 200 or more, preferably 30 or more, in view of the above effects.

As the component (C), generally a phenolic hydroxyl group-containing compound used in a photoresist composition, and if the conditions of the above molecular weight are satisfied, there is no particular limitation, and one or two or more kinds can be arbitrarily selected and used. have. And, among them, the following general formula (4)

[Wherein, R ³¹ to R ³⁸ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms; R ⁴⁰ and R ⁴¹ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; When R ³⁹ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, Q is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a residue represented by the following formula (5):

Wherein R ⁴² and R ⁴³ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a cycloalkyl group having 3 to 6 carbon atoms; c is 1 represents an integer of 2-3), or in combination with the end of the Q is R ³⁹ R ³⁹ and intended to form a cycloalkyl group of 3 to 6 carbon chain, together with the carbon atoms between Q and R ^39; a and b represent the integer of 1-3; d represents an integer of 0 to 3; n represents an integer of 0 to 3]

Together with the carbon atoms between Q and R ^39, and in the case of forming a cycloalkyl group of 3 to 6 carbon chain, the combination is Q and R ³⁹ form an alkylene group having a carbon number of 2-5.

As a phenolic compound corresponding to the said Formula (4), a tris (4-hydroxyphenyl) methane, bis (4-hydroxy-3- methylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,3) , 5-trimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) 3-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -4-hydroxyphenyl Methane, bis (4-hydroxy-2,5-dimethylphenyl) -3-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4- Hydroxy-3,5-dimethylphenyl) -3,4-dihydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -3,4-dihydroxyphenylmethane, bis (4- Hydroxy-2,5-dimethylphenyl) -2,4-dihydroxyphenylmethane, bis (4-hydroxyphenyl) -3-methoxy-4-hydroxyphenylmethane, bis (5-cyclohexyl-4 -Hydroxy Cy-2-methylphenyl) -4-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy- Trisphenol type compounds such as 2-methylphenyl) -2-hydroxyphenylmethane and bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3,4-dihydroxyphenylmethane;

2,4-bis (3,5-dimethyl-4-hydroxybenzyl) -5-hydroxyphenol, 2,6-bis (2,5-dimethyl-4-hydroxybenzyl) -4-methylphenol Linear trinuclear phenolic compounds; 1,1-bis [3- (2-hydroxy-5-methylbenzyl) -4-hydroxy-5-cyclohexylphenyl] isopropane, bis [2,5-dimethyl-3- (4-hydroxy- 5-methylbenzyl) -4-hydroxyphenyl] methane, bis [2,5-dimethyl-3- (4-hydroxybenzyl) -4-hydroxyphenyl] methane, bis [3- (3,5-dimethyl -4-hydroxybenzyl) -4-hydroxy-5-methylphenyl] methane, bis [3- (3,5-dimethyl-4-hydroxybenzyl) -4-hydroxy-5-ethylphenyl] methane, bis [3- (3,5-diethyl-4-hydroxybenzyl) -4-hydroxy-5-methylphenyl] methane, bis [3- (3,5-diethyl-4-hydroxybenzyl) -4- Hydroxy-5-ethylphenyl] methane, bis [2-hydroxy-3- (3,5-dimethyl-4-hydroxybenzyl) -5-methylphenyl] methane, bis [2-hydroxy-3- (2 -Hydroxy-5-methylbenzyl) -5-methylphenyl] methane, bis [4-hydroxy-3- (2-hydroxy-5-methylbenzyl) -5-methylphenyl] methane, bis [2,5-dimethyl Linear tetranuclear phenol compounds such as -3- (2-hydroxy-5-methylbenzyl) -4-hydroxyphenyl] methane; 2,4-bis [2-hydroxy-3- (4-hydroxybenzyl) -5-methylbenzyl] -6-cyclohexylphenol, 2,4-bis [4-hydroxy-3- (4-hydroxy Hydroxybenzyl) -5-methylbenzyl] -6-cyclohexylphenol, 2,6-bis [2,5-dimethyl-3- (2-hydroxy-5-methylbenzyl) -4-hydroxybenzyl] -4 Linear polyphenol compounds such as linear 5-nuclear phenol compounds such as methylphenol; Bis (2,3,4-trihydroxyphenyl) methane, bis (2,4-dihydroxyphenyl) methane, 2,3,4-trihydroxyphenyl-4'-hydroxyphenylmethane, 2- ( 2,3,4-trihydroxyphenyl) -2- (2 ', 3', 4'-trihydroxyphenyl) propane, 2- (2,4-dihydroxyphenyl) -2- (2 ', 4'-dihydroxyphenyl) propane, 2- (4-hydroxyphenyl) -2- (4'-hydroxyphenyl) propane, 2- (3-fluoro-4-hydroxyphenyl) -2- ( 3'-fluoro-4'-hydroxyphenyl) propane, 2- (2,4-dihydroxyphenyl) -2- (4'-hydroxyphenyl) propane, 2- (2,3,4-tri Hydroxyphenyl) -2- (4'-hydroxyphenyl) propane, 2- (2,3,4-trihydroxyphenyl) -2- (4'-hydroxy-3 ', 5'-dimethylphenyl Bisphenol-type compounds such as propane; 1- [1- (4-hydroxyphenyl) isopropyl] -4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene, 1- [1- (3-methyl-4-hydroxyphenyl Multinuclear branched compounds such as) isopropyl] -4- [1,1-bis (3-methyl-4-hydroxyphenyl) ethyl] benzene; And condensed phenol compounds such as 1,1-bis (4-hydroxyphenyl) cyclohexane.

These can be used 1 type or in combination or 2 or more types.

Among these, 1- [1- (4-hydroxyphenyl) isopropyl] -4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene is preferable.

The compounding quantity of (C) component becomes 10-70 mass% with respect to (A) component in consideration of the aspect of an effect, Preferably it is the range of 15-60 mass%.

<(D) component>

The component (D) may be one or two or more types selected without particular limitation, as long as it is a general one used in the photoresist composition, and containing propylene glycol monoalkyl ether acetate and / or alkyl lactate has excellent applicability and large size. It is preferable at the point which is excellent in the film thickness uniformity of the resist film on a glass substrate.

Propylene glycol monoalkyl ether acetate is, for example, having a linear or branched alkyl group having 1 to 3 carbon atoms, and propylene glycol monomethyl ether acetate (hereinafter sometimes abbreviated as PGMEA) may be formed on a large glass substrate. It is particularly preferable because the film thickness uniformity of the resist film is very excellent.

Examples of the alkyl lactate include methyl lactate and ethyl lactate (hereinafter sometimes abbreviated as EL). Among them, ethyl lactate is preferred, but when a large glass substrate of 500 mm x 600 mm or larger is used, coating unevenness tends to occur. Therefore, it is preferable to use it by mixing system with the other solvent which suppresses such a problem.

It is preferable that the compounding quantity of propylene glycol monoalkyl ether acetate shall be 20-100 mass% in (D) component from a viewpoint of the said effect.

It is preferable that the compounding quantity of alkyl lactate is 20-100 mass% in (D) component from the viewpoint of the said effect.

In addition, by using the component (D) containing both propylene glycol monoalkyl ether acetate and alkyl lactate, it is possible to obtain a resist pattern excellent in film uniformity of the resist film and excellent in shape, and further improving heat resistance and scum. It is also preferable at the point of suppressing the occurrence of.

In the case of a mixed system of propylene glycol monoalkyl ether acetate and alkyl lactate, it is preferable to use 0.1 to 10 times by mass, preferably 1 to 5 times alkyl lactate, relative to propylene glycol monoalkyl ether acetate.

In addition, 2-heptanone (hereinafter sometimes abbreviated as HE) is also a preferred organic solvent. Although it does not specifically limit, It is a suitable solvent when combined with the non-benzophenone type photosensitive component as mentioned above.

2-heptanone is a very preferable solvent because it has excellent heat resistance and provides a resist composition with reduced scum generation compared to PGMEA.

It is preferable from the viewpoint of the said effect that 2-heptanone shall be 20-100 mass% in (D) component.

As the other organic solvent which can be mix | blended, the following are specifically mentioned.

Γ-butyrolactone; Propylene glycol monobutyl ether; Ketones such as acetone, methyl ethyl ketone, cyclohexanone and methyl isoamyl ketone; Ethylene glycol, propylene glycol, diethylene glycol, ethylene glycol monoacetate, propylene glycol monoacetate, diethylene glycol monoacetate or polyhydric compounds such as monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether Alcohols and derivatives thereof; Cyclic ethers such as dioxane; And esters such as methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate and ethyl ethoxypropionate.

When using these solvents, it is preferable that it is 50 mass% or less in (D) component.

In the positive photoresist composition of the present invention, additives, plasticizers, preservative stabilizers, surfactants, etc., for improving the performance of the additives, such as resist films, which are compatible as necessary within the scope of not impairing the object of the present invention, Common additives such as colorants for making the developed image more visible, sensitizers for improving the sensitizing effect, anti-halation dyes, and adhesion improving agents can be contained.

Examples of the anti-halation dyes include ultraviolet absorbers (such as 2,2 ', 4,4'-tetrahydroxybenzophenone, 4-dimethylamino-2', 4'-dihydroxybenzophenone and 5-amino-3). -Methyl-1-phenyl-4- (4-hydroxyphenylazo) pyrazole, 4-dimethylamino-4'-hydroxyazobenzene, 4-diethylamino-4'-ethoxyazobenzene, 4-diethylamino Azobenzene, curcumin, etc.) can be used.

Surfactants can be added, for example, for the prevention of striation, and the like, for example, Fluorad FC-430, FC431 (trade name, manufactured by Sumitomo 3M), EFTOP EF122A, EF122B, EF122C, EF126 (trade name, manufactured by Tohkem products), and the like. Fluorine-based surfactants, R-08 (trade name, Dainippon Ink and Chemicals, manufactured by Incorporated), and the like can be used.

The positive photoresist composition of the present invention is preferably prepared by dissolving the component (A), the component (B), the component (C) and, if necessary, other components in the organic solvent (D).

The usage-amount of (D) component, Preferably melt | dissolves (A)-(C) component and other components used as needed, and can adjust suitably so that a uniform positive photoresist composition may be obtained. Preferably the total solid content concentration is 10-40 mass%, More preferably, 20-30 mass% is used.

[Formation method of resist pattern]

Below, an example of the preferable formation method of the resist pattern in manufacture of LCD is shown.

First, the positive photoresist composition of the present invention described above is applied to a substrate with a spinner or the like to form a coating film. As the substrate, a glass substrate is preferable. Amorphous silica is generally used as the glass substrate, and low temperature polysilicon is known to be preferable in the field of system LCD. As this board | substrate, since the positive photoresist composition of this invention is excellent in the resolution under low NA conditions, a large board | substrate of 500 mm x 600 mm or more, especially 550 mm x 650 mm or more can be used.

Subsequently, the substrate on which this coating film is formed is heat-treated (prebaked) at 100-140 degreeC, for example, the residual solvent is removed and a resist film is formed. As a prebaking method, it is preferable to perform the proximity baking which makes the clearance gap between a hotplate and a board | substrate.

Moreover, selective exposure is performed using the mask in which the mask pattern was drawn with respect to the said resist film.

As a light source, it is preferable to use i-ray (365 nm) in order to form a fine pattern. Moreover, it is preferable that the exposure process employ | adopted by this exposure is an exposure process of low NA conditions of NA or less, Preferably it is 0.2 or less, More preferably, it is 0.15 or less.

Next, heat treatment (post exposure bake: PEB) is performed on the resist film after selective exposure. As the PEB method, it is preferable to perform a proximity baking with a gap between the hot plate and the substrate.

When the resist coating after the PEB is developed using a developing solution, for example, an aqueous alkaline solution such as an aqueous solution of 1 to 10 mass% tetramethylammonium hydroxide, the exposed portion is dissolved and removed to form a resist pattern and a liquid crystal for an integrated circuit on a substrate. A resist pattern for the display portion is formed at the same time.

The resist pattern can be formed by washing the developer remaining on the surface of the resist pattern with a rinse solution such as pure water.

In this method of forming a resist pattern, in the case of producing a system LCD, in the step of performing the selective exposure, a mask pattern for forming a resist pattern of 2.0 µm or less and a mask for forming a resist pattern of more than 2.0 µm as the mask. It is preferable to use a mask on which both patterns are drawn.

And since the positive photoresist composition for LCDs of this invention is excellent in resolution, the resist pattern which faithfully reproduced the fine pattern of a mask pattern is obtained. Accordingly, in the step of simultaneously forming the resist pattern, a resist pattern for integrated circuits having a pattern dimension of 2.0 μm or less and a resist pattern for liquid crystal display portions larger than 2.0 μm may be simultaneously formed on the substrate.

As described above, the positive photoresist composition of the present invention is suitable for an exposure process under low NA conditions. It is also suitable for i-ray exposure processes. Therefore, in manufacturing the LCD, at least a resist pattern of the display portion can be obtained with high resolution.

Moreover, since the positive photoresist composition of this invention is excellent also in the resolution under low NA conditions, a rough pattern and a fine pattern can be formed on one board | substrate under the same exposure conditions. Therefore, even under low NA conditions, the display portion of the system LCD and the resist pattern of the finer integrated circuit portion can be obtained at the same time in high resolution, which is suitable for manufacturing the system LCD.

In the positive type photoresist composition for LCD, it is known that high sensitivity is preferable at the point of manufacturing efficiency improvement, throughput, etc., and what is practical also in this point is obtained.

It also has the effect of less scum being generated.

In addition, according to the method for forming a resist pattern of the present invention using the positive photoresist composition having excellent resolution under low NA conditions, throughput in LCD production is improved.

In addition, according to the method for forming a resist pattern of the present invention, a high-resolution resist pattern can be formed even in an exposure process under low NA conditions suitable for LCD production. In particular, since a resist pattern for an integrated circuit having a pattern dimension of 2.0 mu m or less and a resist pattern for a liquid crystal display portion larger than 2.0 mu m, for example, can be simultaneously formed on a substrate, it can be suitably used for the manufacture of a system LCD.

Example

Next, although an Example is shown and this invention is demonstrated in detail, this invention is not limited to a following example.

[Evaluation Method of Positive Photoresist Composition]

About the positive type photoresist composition of the following Example or a comparative example, the evaluation method of the following general physical properties (1)-(3) is shown below.

(1) sensitivity evaluation:

The positive photoresist composition was applied onto a glass substrate (550mm × 650mm) on which a Cr film was formed by using a resist coating device for large square substrates (device name: TR36000, manufactured by TOKYO OHKA KOGYO CO., LTD.), And then the temperature of the hot plate. Is 130 degreeC, the 1st drying for 60 second is carried out by the proximal bake which spaced about 1 mm, and then the temperature of a hotplate is 120 degreeC, and 60 by the proximal bake which spaced 0.5 mm is carried out. Second drying for a second time was performed to form a resist film having a thickness of 1.5 m.

Next, an i-ray exposure apparatus (device name: FX-702J, manufactured by Nikon) was manufactured through a test chart mask (reticle) on which a mask pattern for reproducing a resist pattern of 3.0 mu m line and space (L & S) and a 1.5 mu m L & S was simultaneously drawn; Selective exposure was performed using the exposure amount (Eop exposure amount) which can reproduce 3.0 micrometers L & S faithfully using NA = 0.14).

Subsequently, using a developing apparatus (apparatus name: TD-39000 Demonstrator, manufactured by TOKYO OHKA KOGYO CO., LTD.) Having a slit coater nozzle in a 2.38% by mass TMAH aqueous solution, Y was determined at the substrate end X as shown in FIG. After 10 seconds to Z, the liquid was placed on the substrate, held for 55 seconds, washed with water for 30 seconds, and spin-dried to simultaneously form a resist pattern of 3.0 µm L & S and a resist pattern of 1.5 µm L & S on the substrate.

The Eop exposure amount at this time was expressed in mJ units with sensitivity.

(2) Resolution evaluation: The limit resolution in the said Eop exposure amount was calculated | required.

(3) Scum evaluation: The surface of the board | substrate in which 1.5 micrometer L & S was drawn in the said Eop exposure amount was observed by SEM, and the presence or absence of scum was investigated. The evaluation result is shown by the following symbol.

(Circle): The generation of scum was hardly confirmed.

(Triangle | delta): It was confirmed that the scum arose slightly.

X: It was confirmed that a large amount of scum was generated.

Example 1

The following were prepared as (A)-(D) component.

(A) 100 parts by mass of alkali-soluble novolak resin

A1: The novolak resin of Mw = 6000 and Mw / Mn = 4.0 obtained by synthesizing by a conventional method using 0.8 mol of formaldehyde with respect to 1 mol of mixed phenols of m-cresol / p-cresol (molar ratio 7/3).

(B) 30 parts by mass of esterification product (PAC1 / PAC3 = 2/1 (mass ratio))

PAC1: esterification reaction of Mw1300 pyrogarol-acetone resin prepared as a polycondensate of pyrogarol and acetone with 1,2-naphthoquinone diazide-5-sulfonic acid chloride (5-NQD) with an esterification rate of 78% product.

PAC3: Bis (2,3,5-trimethyl-4-hydroxyphenyl) -2-hydroxyphenylmethane (M (molecular weight) prepared as a condensate of 2,3,6-trimethylphenol and 2-hydroxybenzaldehyde ) = 376) esterification product with esterification rate of 67.3% of 1 mole to 2.02 moles of 5-NQD.

(C) 20 parts by mass of phenolic hydroxyl group-containing compound

1- [1- (4-hydroxyphenyl) isopropyl] -4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene

(D) organic solvent

D1: PGMEA

Surfactant (product name "R-08": Dainippon Ink and Chemicals, manufactured by Incorporated) in an amount equivalent to 350 ppm relative to the total mass of the components (A) to (C) and these components (A) to (C) It dissolved in PGMEA which is (D) component, it adjusted so that solid content [the sum of (A)-(C) component] concentration might be 25-28 mass%, this was filtered using the membrane filter of 0.2 micrometer of pore diameters, and was positive type. A photoresist composition was prepared.

Examples 2 to 9, Comparative Examples 1 to 4

A positive photoresist composition was prepared in the same manner as in Example 1 except that the components (B) and (D) were replaced with those shown in Table 1 below.

(B) (D) (mass ratio)   Example One PAC1 / PAC3 (2/1) PGMEA 2 PAC2 / PAC3 (2/1) PGMEA 3 PAC2 / PAC3 (1/2) PGMEA 4 PAC1 / PAC3 (2/1) EL 5 PAC1 / PAC3 (2/1) EL / PGMEA (7/3) 6 PAC1 / PAC3 (2/1) HE 7 PAC8 / PAC3 (2/1) PGMEA 8 PAC9 / PAC3 (2/1) PGMEA 9 PAC10 / PAC3 (2/1) PGMEA Comparative example One PAC4 PGMEA 2 PAC5 PGMEA 3 PAC6 PGMEA 4 PAC7 PGMEA

In Table 1, EL / PGMEA (7/3) shows that EL / PGMEA was mixed at a mass ratio of 7/3 to the component (D).

In addition, PAC2-10 is as follows.

PAC2: bis (2-methyl-4-hydroxy-5-cyclohexylphenyl) -3,4-di prepared as a condensate of 3-methyl-6-cyclohexylphenol and 3,4-dihydroxybenzaldehyde Esterification product with an esterification rate of 52.75% of 1 mole of hydroxyphenylmethane (M = 500) and 2.11 moles of 5-NQD.

PAC3: Bis (2,3,5-trimethyl-4-hydroxyphenyl) -2-hydroxyphenylmethane (M = 376) prepared as a condensate of 2,3,6-trimethylphenol and 2-hydroxybenzaldehyde ) Esterification product of 67.3% of esterification rate with 1 mole and 2.02 moles of 5-NQD.

PAC4: M-cresol / p-cresol / 2,3,5-trimethylphenol = 35: 40: 25 (molar ratio) Mw 1500 novolak resin prepared as a polycondensate of formaldehyde and 5-NQD esterification rate 8% esterification product.

PAC5: The esterification product of 94% of esterification ratio of 1 mol of bis (2,4-dihydroxyphenyl) methane (M = 232) with 3.76 mol of 5-NQD.

PAC6: The esterification product of 66.7% of esterification ratio of 1 mol of tris (4-hydroxyphenyl) methane (M = 292) with 2 mol of 5-NQD.

PAC7: The esterification reaction product of 100% of esterification rate of 1 mol of methyl gallate esters, and 3 mol of 5-NQD.

PAC8: M = 376 2,6-bis (2,5-dimethyl-4-hydroxybenzyl) which synthesize | combined 2, 5- xylenol / p-cresol (molar ratio 2/1) and formaldehyde to a raw material An esterification reaction product having an esterification rate of 66% between 1 mol of 4-methylphenol and 2 mol of 5-NQD.

PAC9: M = 376 2,6-bis (3,5-dimethyl-4-hydroxybenzyl) which synthesized 2,6-xylenol / p-cresol (molar ratio 2/1) and formaldehyde in a raw material An esterification reaction product having an esterification rate of 66% between 1 mol of 4-methylphenol and 2 mol of 5-NQD.

PAC10: bis [3- (2-hydroxy-5-methyl of M = 632 obtained by synthesizing 2-cyclohexylphenol / p-cresol (molar ratio 1/1) and formaldehyde / acetone (molar ratio 2/1) to the raw materials Ester reaction product of 50% of esterification rate of 1 mol of benzyl) -4-hydroxy-5-cyclohexylphenyl] isopropane with 2 mol of 5-NQD.

Sensitivity evaluation (mJ) Resolution Evaluation (㎛) Scum Reviews   Example One 30 1.3 ○ 2 30 1.3 ○ 3 42.5 1.2 ○ 4 35.0 1.3 ○ 5 32.5 1.3 ○ 6 37.5 1.3 ○ 7 37.5 1.1 ○ 8 40.0 1.1 ○ 9 47.5 1.3 △ Comparative example One 30 1.6 × 2 37.5 1.5 × 3 30 1.5 × 4 25 1.6 ○

As positive type photoresist composition for LCD, high resolution under low NA conditions is calculated | required.

As is clear from the results shown in Table 2, the compositions of the examples all had good resolution.

Moreover, the sensitivity was also good enough to be practical, and there was no scum, and it was also favorable in this respect.

On the other hand, the composition of the comparative example 1 had too high molecular weight, and was poor in resolution. In addition, scum also occurred.

The composition of Comparative Example 2 had a poor resolution because the esterification rate exceeded 90%. Also, the scum was slightly bad.

The composition of Comparative Example 3 had a low molecular weight and poor resolution. In addition, scum also occurred.

Since the composition of Comparative Example 4 did not have a skeleton of a low molecular weight novolak resin, the sensitivity was too fast and the resolution was also poor.

The method for producing a positive photoresist composition and resist pattern for an LCD of the present invention provides good resolution even under low NA conditions, and therefore is suitable for the production of system LCDs and is very useful industrially.

Claims (13)

(A) alkali-soluble resin, (B) an esterification reaction product having an average esterification rate of 30 to 90% between a low molecular weight novolak resin having a polystyrene-reduced mass average molecular weight of 300 to 1300 and a naphthoquinone diazide sulfonic acid compound, (C) a phenolic hydroxyl group containing compound whose molecular weight is 1000 or less, (D) Positive type photoresist composition for LCD manufacture containing an organic solvent. The method of claim 1, wherein the low molecular weight novolak resin, Formula 1 [Formula 1]

(Wherein R ¹ to R ⁵ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, two of R ¹ , R ³ and R ⁵ are hydrogen atoms, and one is an alkyl group having 1 to 5 carbon atoms) A positive photoresist composition for LCD production, comprising a low molecular weight novolak resin that can be synthesized by condensation of a bifunctional phenol compound represented by &lt; RTI ID = 0.0 &gt;&lt; / RTI &gt; The method of claim 1, wherein the low molecular weight novolac resin, Formula 1 [Formula 1]

(Wherein R ¹ to R ⁵ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, two of R ¹ , R ³ and R ⁵ are hydrogen atoms, and one is an alkyl group having 1 to 5 carbon atoms) Bifunctional phenolic compounds represented by Formula 2 [Formula 2]

Wherein R ¹¹ to R ¹⁵ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, one of R ¹¹ , R ¹³ and R ¹⁵ is a hydrogen atom, and two are hydrogen atoms of 1 to 5 carbon atoms. Monofunctional phenolic compound represented by And a low molecular weight novolak resin that can be synthesized by condensation with aldehydes and / or ketones. The method of claim 1, wherein the low molecular weight novolac resin, Formula 1 [Formula 1]

(Wherein R ¹ to R ⁵ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, two of R ¹ , R ³ and R ⁵ are hydrogen atoms, and one is an alkyl group having 1 to 5 carbon atoms) Bifunctional phenolic compounds represented by To condensates that can be synthesized by condensation with aldehydes and / or ketones, Formula 2 [Formula 2]

Wherein R ¹¹ to R ¹⁵ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, one of R ¹¹ , R ¹³ and R ¹⁵ is a hydrogen atom, and two are hydrogen atoms of 1 to 5 carbon atoms. An alkyl group. A positive photoresist composition comprising a low molecular weight novolak resin which can be synthesized by reacting a monofunctional phenol compound represented by the formula (I). The positive type photoresist composition according to any one of claims 1 to 4, wherein the component (D) contains propylene glycol monoalkyl ether acetate. The positive type photoresist composition according to claim 1, wherein the component (D) contains an alkyl lactate. The positive type photoresist composition according to claim 1, wherein the component (D) contains 2-heptanone. A positive photoresist composition according to claim 1, which is for an i-ray exposure process. The positive type photoresist composition according to claim 1, wherein NA is for an exposure process of 0.3 or less. The positive type photoresist composition according to claim 1, wherein the positive photoresist composition is for LCD production in which an integrated circuit and a liquid crystal display portion are formed on one substrate. (1) Process of apply | coating positive type photoresist composition of Claim 1 on a board | substrate, and forming a coating film, (2) heat-treating (prebaking) the substrate on which the coating film is formed and forming a resist film on the substrate; (3) a step of performing selective exposure to the resist film using a mask on which both a resist pattern forming mask pattern of 2.0 μm or less and a mask pattern for resist pattern forming of more than 2.0 μm are drawn; (4) performing a heat treatment (post exposure bake) on the resist film after the selective exposure; (5) A development process using an aqueous alkali solution is performed on the resist film after the heat treatment, and a resist pattern for integrated circuits having a pattern dimension of 2.0 μm or less and a resist pattern for liquid crystal display portions larger than 2.0 μm are simultaneously formed on the substrate. Process, (6) A method of forming a resist pattern, comprising a rinsing step of washing away the developer remaining on the resist pattern surface. The method of forming a resist pattern according to claim 11, wherein the step (3) of performing selective exposure is performed by an exposure process using i-line as a light source. The method of forming a resist pattern according to claim 11, wherein the step (3) of performing selective exposure is performed by an exposure process under low NA conditions of NA of 0.3 or less.

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