JPH07104467A - Positive resist composition and pattern forming method - Google Patents

Abstract

PURPOSE:To provide a positive resist composition having high sensitivity, a high residual film rate and a high resolution. CONSTITUTION:The composition features that alkali soluble resin is blended with the 1,2-quinone diazide compound expressed by the formula where R stands for a methyl group or a hydrogen atom, R<1> to R<4> for a 2-quinone diazide sulfonyl group or a hydrogen atom. Also, at least one of R<1> to R<4> is a 1,2-quinone diazide sulfonyl group. Also, (n) shows an integer selected from the figures of 0 to 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-performance positive resist composition and a pattern forming method using the composition.

[0002]

2. Description of the Related Art Positive resists have been widely used in the manufacture of integrated circuits since they are capable of obtaining high-resolution resist patterns. However, recent integrated circuits are highly integrated, and a resist with higher resolution is required. In addition, the investment in integrated circuit manufacturing equipment is enormous, and it is necessary to manufacture integrated circuits with high throughput in order to depreciate the equipment, and the positive resist used there has higher sensitivity. Therefore, it is required that patterning can be completed in a shorter time.

For example, TF which is considered as a kind of integrated circuit
Although positive type resists are often used in the manufacture of T (Thin Film Transistor) liquid crystal substrates, the priority here is to increase the throughput and to reduce the cost of the TFT liquid crystal substrate, in particular in conventional semiconductor integrated circuits. It is required to have a sensitivity as high as about 10 times that of the positive resist used.

In such a situation, a method of reducing the ratio of the photosensitizer and increasing the sensitivity from the ratio of the alkali-soluble resin and the benzophenone type photosensitizer which have been conventionally used has been studied, but the film reduction is caused. However, various problems such as profile deterioration due to the above remain.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a positive resist composition having high resolution, high sensitivity, and high resolution, and a pattern forming method using the composition. To do.

[0006]

Means and Actions for Solving the Problems As a result of intensive studies for achieving the above-mentioned object, the present inventor has found that the alkali-soluble resin is represented by the following general formula (1):
By using a quinonediazide compound in combination as a photosensitizer, a positive resist composition with high sensitivity and high residual film rate and high resolution can be obtained. A resist film is formed using this resist composition and prebaked. Since the pattern obtained by exposure and development does not have film reduction like this, there is no problem of profile deterioration and the resolution is high.
The present invention has been completed by finding that it is advantageous in producing various substrates such as liquid crystal substrates.

[0007]

[Chemical 2](However, in the formula R Is a methyl group or a hydrogen atom, R
¹~ R^FourIs a 1,2-quinonediazidesulfonyl group or
Hydrogen atom and R¹~ R^FourAt least one of
It is a 2-quinonediazidesulfonyl group. Also, n is 0
An integer selected from 2 to 3 is shown. )

Therefore, the present invention is based on a positive resist composition obtained by blending an alkali-soluble resin with the 1,2-quinonediazide compound represented by the above general formula (1), and on the basis of this resist composition. A method for forming a pattern is provided, which comprises applying the composition to a substrate, pre-baking, exposing, and then developing.

The present invention will be described in more detail below. The alkali-soluble resin used in the present invention may be any alkali-soluble resin conventionally used in positive resist compositions. A novolac resin synthesized by condensing at least one phenol represented by the formula (2) with an aldehyde is preferable.

[0010]

[Chemical 3] (However, m = 1 to 3 represents an integer.)

In this case, the aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde and the like, with formaldehyde being preferred. The mixing ratio of phenols and aldehydes is 0.3 for aldehydes and phenols.
It is preferable to use it in a molar ratio of ˜2.

The average molecular weight of the alkali-soluble resin used in the present invention is preferably 2,000 to 10,000 in terms of polystyrene equivalent weight average molecular weight.

In the positive resist composition of the present invention, the 1,2-quinonediazide compound represented by the following general formula (1) is blended with the above alkali-soluble resin.

[0014]

[Chemical 4](However, in the formula R Is a methyl group or a hydrogen atom, R
¹~ R^FourIs a 1,2-quinonediazidesulfonyl group or
Hydrogen atom and R¹~ R^FourAt least one of
It is a 2-quinonediazidesulfonyl group. Also, n is 0
An integer selected from 2 to 3 is shown. )

The 1,2-quinonediazide compound of the formula (1) is obtained by substituting at least one OH group of the ballast molecule represented by the general formula (3) with a 1,2-quinonediazidesulfonyl group. Used as a photosensitizer.

[0016]

[Chemical 5]

The ballast molecule represented by the formula (3) can be synthesized by condensing the resolecinol and the phenol represented by the general formula (2) with formaldehyde, and the ballast molecule represented by the formula (3) and the general formula (4). It can also be synthesized by condensation with a methylol represented by

[0018]

[Chemical 6]

Here, the 1,2-quinonediazidesulfonyl group of R ^{1 to} R ⁴ is a 1,2-naphthoquinonediazide-4-sulfonyl group, a 1,2-naphthoquinonediazide-5-sulfonyl group or the like. Is preferred.

The content of the 1,2-quinonediazide compound is 10 to 100 parts by weight of the alkali-soluble resin.
The amount is preferably 40 parts by weight, more preferably 12 to 30 parts by weight. If the amount is less than 10 parts by weight, the residual film rate decreases, and 4
If it is more than 0 parts by weight, the sensitivity may decrease.

In the composition of the present invention, a sensitizer may be added to improve the sensitivity to radiation, a surfactant may be added to improve the coatability, and a composition on a highly reflective substrate may be added. Dyes and pigments can be added to prevent the standing wave.

Here, benzotriazole, benzophenone, pyrrole, imidazole, etc. are used as the sensitizer, and polyoxyethylene alkyl ethers, silicone-based surfactants, fluorine-based surfactants, etc. are used as the surfactants. To be Examples of dyes and pigments include basic dyes, methine dyes and azo dyes.

The compounding amount of the sensitizer is 0 to 30 parts by weight, particularly 0.1 to 100 parts by weight of the alkali-soluble resin.
10 parts by weight is preferable, and the compounding amount of the surfactant is 0 to 5 parts by weight, particularly 0.001 to 1 part by weight, relative to 100 parts by weight of the alkali-soluble resin.

The positive resist composition of the present invention can be used in the same manner as a normal positive resist composition. It is applied to a substrate such as a semiconductor integrated circuit, prebaked according to a conventional method, exposed, and then exposed. It is to develop.

In this case, as a method for applying the composition of the present invention onto a silicone wafer or a glass substrate with a transparent conductive film, a predetermined amount of an alkali-soluble resin or a 1,2-quinonediazide compound, for example, a solid content is used. Concentration is 15 ~
Dissolve in a solvent so as to be 55% by weight, for example 0.1 μ
A method of filtering with a filter having a pore size of m and applying this by spin coating can be mentioned.

Examples of the solvent used at this time include ethyl cellosolve acetate (ECA), ethyl lactate (EL), propylene glycol methyl ether acetate (PGMEA), butyl acetate (BA),
3-methyl-3-methoxybutyl propionate (MM
P), cyclohexanone (CH) and the like. These solvents may be used alone or as a mixture.

The coating film thickness of the composition of the present invention on the substrate is preferably 0.1 to 50 μm, more preferably 0.1 to 5 μm.

The prebaking, exposure, and developing methods and conditions can be conventional methods as described above, but the prebaking remains in the resist film applied using a hot plate or a drier. The condition is such that the solvent can be further removed by evaporation, and heating is usually performed at a temperature of 60 to 110 ° C. for several tens of seconds to several tens of minutes.

The exposure is carried out with a single UV light such as g-ray, h-ray, i-ray or the like or a broadband UV light in which these lights are mixed, and a device such as a stepper or an aligner is used.

On the other hand, an alkaline aqueous solution is used for the development, but a 1-5% by weight aqueous solution of tetramethylammonium hydroxide (TMAH) is particularly preferred.

[0031]

The positive resist composition of the present invention has a high sensitivity, a high residual film ratio and a high resolution, and a resist pattern obtained by using this has a high resolution without a problem of profile deterioration. It is a thing.

[0032]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited to the following examples. The evaluation of various resist performances described in the examples was performed by the following methods. (1) Average molecular weight of alkali-soluble resin M _W Toyo Soda GPC column (G2000H ₆ 2 pieces, G
3000H ₆ 3 present, using G4000H ₆ 1 present), flow rate 1.5 ml / min, eluent tetrahydrofuran, was measured by a GPC method using monodispersed polystyrene as a standard in the analysis conditions column temperature 40 ° C.. (2) Alkali Solubility of Alkali-Soluble Resin Alkali-soluble resin is dissolved in ECA solvent with a solid content of 35% and applied to a 6 ″ Si wafer at 2,000 times,
Soft baking was performed on a hot plate at 90 ° C. for 90 minutes to obtain a resin film having a thickness of about 3 μm. This is applied to a development process monitor (PMS-601) manufactured by Dainippon Screen, and 2.
The film was developed with 38% TMAH, the time until the residual film became zero was measured, the initial film thickness was divided by the time when the residual film became zero, and the alkali solubility was expressed in angstrom / sec (Å / sec). (3) Esterification rate Phenolic O of the compound represented by the general formula (3)
Molecular weight per H group (Molecular weight of compound is O in 1 molecule)
(Value divided by the number of H groups) is defined as OHvalue, and this OHvalue is considered as a virtual molecular weight per one OH group, and the ratio of 1,2-quinonediazidesulfonyl groups introduced here is expressed as the number of moles at the time of charging. It is the ratio at the time of thinking. (4) Resist film thickness Spin coater manufactured by Dainippon Screen (SKW-636-
BV) was used to apply the prepared resist composition onto a HMDS-treated Si wafer, and soft bake was performed on a hot plate at 90 ° C. for 90 minutes.
The resist film thickness was measured with 10 (trade name: optical film thickness measuring device). (5) Optimal exposure amount E _op Nikon i-line (365 nm) exposure apparatus X / SR-17
After exposure with changing the exposure time at 55i7A (numerical aperture NA = 0.50), a 2.38% aqueous solution of tetramethylammonium hydroxide (TMAH) was used as a developing solution and paddle at 23 ° C. for 65 seconds. After developing and rinsing with pure water, spin drying was performed. Then, the exposure energy when a 1.0 μm line-and-space pattern was formed with a width of 1: 1 with an electron microscope (S-4100) manufactured by Hitachi Ltd. was defined as the optimum exposure amount E _op, and was determined. . (6) Resolution The dimension of the smallest resist pattern resolved when exposed at the optimum exposure time was measured and defined as the resolution. (7) Residual film rate The value obtained by dividing the film thickness of the unexposed portion of the pattern exposed by the optimum exposure amount by the film thickness before exposure was expressed as a percentage to obtain the residual film rate.

[Synthesis Example 1] Alkali-soluble resin In a three-necked flask equipped with a stirrer, a condenser, and a thermometer, 64.9 g (0.60 mol) of p-cresol and m-
Cresol 43.3 g (0.40 mol), 37 wt% formaldehyde aqueous solution 44.6 g (0.55 mol) and oxalic acid dihydrate 0.30 g (2.4) as a polycondensation catalyst.
(× 10 ⁻³ mol) was charged, the flask was immersed in an oil bath, the internal temperature was kept at 100 ° C., and polycondensation was carried out for 1 hour.

After the reaction was completed, 500 ml of MIBK (methyl isobutyl ketone) was added, and the mixture was stirred for 30 minutes, then the aqueous layer was separated, and the product extracted in the MIBK layer was 300 m.
After rinsing with 1 l of pure water 5 times to separate the liquid, a vacuum strip at 150 ° C. was performed with an evaporator at 4 mmHg. As a result, 87 g of novolak resin A-1 was recovered.

Further, as in the case of novolac resin A-1,
The novolak resins A-2 to A-4 shown in Table 1 were synthesized.

[0036]

[Table 1]

[Synthesis Example 2] 1,2-quinonediazide compound In a flask equipped with a stirrer, a dropping funnel and a thermometer, 10.0 g (119 mmol) of the resorcyl derivative shown in Table 1 and 1,2-naphtho were protected from light. 24.0 g (89.2 mmol) of quinonediazide-4-sulfonyl chloride was added to 20
It was dissolved in 0 g of 1,4-dioxane. Flask 25
In order to control the temperature below ℃, dip it in a water bath and add 1,4-diazabicyclo [2,2,2] octane (DABCO) 10.50 g to 1,4-dioxane 10
The catalyst dissolved in 0 g was dropped using a dropping funnel. Then, the precipitated DABCO hydrochloride was filtered off,
The filtrate was dropped into 1,800 g of 0.12N hydrochloric acid water with stirring to reprecipitate. It is further filtered and the reprecipitate is washed with 3
Extract into 00 ml of ethyl acetate and add 5 g of 100 g of pure water.
It was washed with water and separated. This was further stripped by an evaporator at 40 ° C. or lower to obtain 26 g of 1,2-quinonediazide compound B-1.

Further, the 1,2-quinonediazide compounds B-2 to B-5 shown in Table 2 were synthesized in the same manner as the 1,2-quinonediazide compound B-1.

[0039]

[Table 2]

Examples 1 to 10 To 100 parts by weight of the alkali-soluble resin shown in Table 3, the 1,2-quinonediazide compound shown in Table 3 and the solvent shown in Table 3 were added and mixed,
After forming a uniform solution, it was filtered through a membrane filter having a pore size of 0.2 μm to prepare a resist solution of the composition of the present invention.

The obtained resist solution was applied onto a 6 ″ silicone wafer and soft-baked at 90 ° C. for 90 seconds to form a resist film having a thickness of 1.05 μm.

Then, a wavelength of 365 nm is passed through the reticle.
After irradiation with (i-line) radiation, development, rinsing with pure water, and drying, the performance of the resist was evaluated, and the sensitivity, resolution, and residual film rate were determined. The results are shown in Table 3.

[0043]

[Table 3]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location H01L 21/027 (72) Inventor Miki Kobayashi 1 Hitomi, Osamu Matsuida-cho, Usui-gun, Gunma 10 Shin-Etsu Chemical Industrial Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Kazuhiro Nishikawa 1 Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Hiroshi Kanbara Usui-gun, Gunma Prefecture Matsuida-machi Oji Hitomi 1-10 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Mitsuo Umemura Gunma Prefecture Usui-gun Matsuida-cho Daiji Hitomi 10 Shin-Etsu Chemical Industrial Silicone Electronic Materials Research Institute

Claims (2)

[Claims] 1. The following for (A) alkali-soluble resin:
1,2-quinonediazide compound represented by the general formula (1)
A positive resist composition characterized by containing
Stuff. [Chemical 1](However, in the formula R Is a methyl group or a hydrogen atom, R
¹~ R^FourIs a 1,2-quinonediazidesulfonyl group or
Hydrogen atom and R¹~ R^FourAt least one of
It is a 2-quinonediazidesulfonyl group. Also, n is 0
An integer selected from 2 to 3 is shown. ) 2. A pattern forming method, which comprises applying the resist composition according to claim 1 on a substrate, pre-baking, exposing, and then developing.