JPH1124285A - Developing solution for resist - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the developing solution for the resist capable of forming a resist pattern good in emulsion uniformity and film endurance characteristics and pattern forms and small in dependence on a development process. SOLUTION: This developing solution for the resist is composed essentially of an organic base containing no metal ion, and a propylene-oxide-ethylene-oxide block copolymer surfactant is added in an amount of 10-500 ppm. This copolymer surfactant to be favorably used is represented by the formula: HO(C2 H4 O)k -(C3 H6 O)m -(C2 H4 O)n H or HO(C3 H6 O)p -(C2 H4 O)q -(C3 H6 O)r H, where each of k, m, n, p, q, and r is a same or different integer. This developing solution is preferably used for developing a positive resist.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing solution for resist, and more particularly, to a developing solution having good wettability to a resist film, no generation of bubbles, and uniformity of development even in development using a small amount of developing solution. The present invention relates to a resist developer which can obtain a resist pattern having good film characteristics and pattern shape and does not adversely affect the performance of the resist, and can be preferably used for developing a positive photoresist.

[0002]

2. Description of the Related Art Conventionally, when a semiconductor integrated circuit device, a mask for manufacturing an integrated circuit, a liquid crystal display device, a color filter, a printed wiring board, a printed board, and the like are manufactured, the substrate is selectively etched or diffused, or the like. Photolithography technology is used for forming pixels and the like. As a method of forming a resist image using a photolithography technique, a radiation-sensitive composition that is usually sensitive to actinic rays such as ultraviolet rays, X-rays, and electron beams, a so-called photoresist, is spin-coated, roller-coated, and dipped on a substrate. A known method or a known method is used for coating, exposure to radiation such as ultraviolet rays, electron beams, X-rays, and the like, followed by development using an alkaline developer. This photoresist is classified into a positive type and a negative type. The former is a type in which an exposed portion is dissolved in a developing solution, but the non-exposed portion is not dissolved, and the latter is an opposite type. In recent years, the electronics industry has been remarkably developed, and as a result, high integration of semiconductor elements is required, and resists with high resolution are required, and positive resists with excellent resolution are often used as resists. It has become. Typical positive photoresists include quinonediazide-type photoresists composed of an alkali-soluble novolak resin and a naphthoquinonediazide compound as a photosensitizer, and chemically amplified resists. On the other hand, in the case of manufacturing semiconductor devices and the like, the use of an alkaline aqueous solution containing metal ions as a developing solution adversely affects product characteristics. Therefore, bases containing no metal ions, such as tetramethylammonium hydroxide (IBM “Technical Technical Disclosure Bulletin
13, 7, 2009, 1970) and aqueous solutions of organic bases such as 2-hydroxyethyltrimethylammonium (choline) hydroxide (U.S. Pat. No. 4,239,661) have been used as developers.

[0003] By the way, the photoresist development method includes:
Various methods such as an immersion developing method, a spray developing method, a paddle developing method, a swing developing method, and a static developing method are known, and the paddle developing method is widely used as a developing method in the manufacture of integrated circuits. In the paddle developing method, the wettability of the developer to the resist film is important. In particular, in recent years, the diameter of a wafer has been increased, and in order to obtain a uniform and high-quality fine resist image on a large-diameter wafer, the wettability of the developer is further increased. Is becoming increasingly important. In order to obtain a high-quality fine resist image, it is also extremely important to strictly control the development time between the resist film and the developer. This is because, in the short-time development, the exposed portion that should be removed by the development is not sufficiently removed, and a film residue occurs. On the other hand, in the long-time development, the adhesiveness between the resist and the substrate is reduced, and the unexposed portion is reduced. This is because an undercut occurs at the substrate interface and the yield decreases rapidly. Further, if the wettability of the developer is poor, it is difficult to make the contact time between the developer and the resist film the same over the entire wafer, and therefore, there is a problem that uniform development over the entire wafer is difficult. Usually, an alkaline aqueous solution is used as a resist developing solution. However, when a surfactant is not used, the wettability of the developing solution with respect to the resist is not good. It has been proposed to add an activator (see, for example, JP-A-58-5).
No. 7128, JP-A-62-32453, JP-A-1-257846, etc.) and practical use.
However, when a surfactant is added to the developing solution, bubbles are easily generated, and the bubbles may hinder contact between the resist and the developing solution, and may cause poor development such as residual film. An antifoaming agent is also added to the developer for defoaming the foam (for example, JP-A-49-91177, JP-A-5-197177).
No. 9-182444), however, those having a remarkable effect, such as a silicon-based antifoaming agent, have a problem that development failure is likely to occur or a temporary defoaming effect is recognized, but there is no sustainability. Further, when a surfactant is added to the developer for a positive photoresist, there is a problem that the sensitivity is increased and the amount of film reduction in an unexposed portion is increased. In addition, the addition of a surfactant improves the dissolving power of the developer and increases the dissolution rate of the unexposed portion, resulting in a decrease in the solubility difference between the exposed portion and the unexposed portion of the resist film. Occurs, and as a result, the resist shape after development becomes a trapezoid instead of a rectangle,
There is also a problem that image quality is impaired. Further, the solubility of the added surfactant is also an important requirement. this is,
If the surfactant is present in the developer without being dissolved, the solid or gel-like undissolved material becomes a source of contamination (so-called contaminant) at the time of fabricating the semiconductor circuit or a defect of the resist pattern. Because

As described above, the developing solution for resist includes:
(1) The dissolution contrast between the exposed part and the unexposed part is high,
(2) good wettability to the resist surface, (3) excellent development uniformity over the entire development area, (4) bubbles are hardly generated, and even if they are generated, they are quickly defoamed. Less process dependence on temperature, time, method, etc.
Various conditions such as (6) no adverse effect on the properties of the resist, (7) good solubility of the additive component in the developer, and (8) good characteristics can be obtained by using a small amount of the additive component. It is necessary to meet. Further, in recent years, there has been an increase in awareness of environmental problems, and in order to cope with this, there has been an increasing demand for reducing the amount of developer used as much as possible from the viewpoint of reducing the absolute amount of waste liquid and also from the economic viewpoint.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a developer which satisfies the characteristics required for the above-mentioned resist developer, that is, the wettability to the resist film, the exposed portion and the non-exposed portion. Good dissolution selectivity of the part, no generation of bubbles, good resist uniformity, residual film characteristics and pattern shape can be obtained even when developing with a small amount of developing solution It is an object of the present invention to provide a resist developer which has a low property and does not adversely affect the performance of the resist and can be developed with a small amount of use.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a propylene oxide-ethylene oxide block copolymer surfactant is used in a resist developing solution mainly containing an organic base containing no metal ion. It has been found that the above object can be achieved by adding a specific amount of

That is, according to the first aspect of the present invention, a propylene oxide-ethylene oxide block copolymer surfactant is added in an amount of 10 to 500 ppm to a resist developer mainly containing an organic base containing no metal ions. A developing solution for resist.

[0008] In a second aspect of the present invention, there is provided the resist developer according to the first aspect, wherein the propylene oxide ethylene oxide block copolymer surfactant is a propylene oxide represented by the following general formula (I): A resist developer comprising an ethylene oxide block copolymer.

Formula (I) HO (C ₂ H ₄ O) _k- (C ₃ H ₆ O) _m- (C ₂ H ₄
O) _n H (where k, m and n represent the same or different integers, respectively.) The invention of claim 3 of the present invention provides the resist developer of claim 1, wherein A resist developer, wherein the copolymer surfactant is a propylene oxide ethylene oxide block copolymer represented by the following general formula (II).

General formula (II) HO (C ₃ H ₆ O) _p- (C ₂ H ₄ O) _q- (C ₃ H ₆
O) _r H (wherein p, q, and r each represent the same or different integers.) The invention of claim 4 of the present invention relates to a propylene oxide ethylene oxide block represented by the above general formula (I). The resist developer according to claim 2, wherein the molecular weight of polypropylene oxide in the polymer is 900 to 3500, and the ratio of polyethylene oxide is 10 to 30% by weight.

The invention according to claim 5 of the present invention is characterized in that the resist developer is a positive resist developer. Liquid.

Hereinafter, the present invention will be described in more detail.

In the resist developing solution of the present invention, an organic base containing no metal ion is used as an alkali component. It is conventionally known to use an organic base containing no metal ion as an alkali component of a resist developer. In the present invention, any of these known organic bases containing no metal ion can be used. Examples of the organic base containing no metal ion that can be used in the present invention include lower alkyl quaternary ammonium bases such as tetramethylammonium hydroxide (TMAH) and 2-hydroxyethyltrimethylammonium hydroxide (choline); monomethylamine , Dimethylamine, trimethylamine, monoethylamine, diethylamine,
Linear or branched alkyl or aryl substituted primary, secondary or tertiary amines such as triethylamine; alkanolamines such as ethanolamine; alkylenediamines such as 1,3-diaminopropane; Arylamines such as 4,4'-diaminodiphenylamine; imines such as bis- (dialkylamino) imine; heterocyclic bases such as pyrrole, pyrrolidine, pyrrolidone, pyridine, morpholine, pyrazine, piperidine, oxazole, thiazole and the like. Of these, particularly preferred are tetramethylammonium hydroxide and 2-hydroxyethyltrimethylammonium hydroxide. These organic bases containing no metal ion may be used alone or in combination of two or more. The concentration is 1% by weight or more.
It can be used in an amount of 10% by weight, preferably 1.5% by weight to 5.5% by weight.

The surfactant used in the resist developer according to the present invention is a propylene oxide / ethylene oxide block copolymer surfactant. The propylene oxide ethylene oxide block copolymer surfactant, typically have the general _{formula: HO (C 2 H 4 O} ) k - (C 3 H 6 O) m - (C 2 H 4 O) n H A normal type propylene oxide ethylene oxide block copolymer represented by (I), and a general formula: HO (C ₃ H ₆ O) _p- (C ₂ H ₄ O) _q- (C ₃ H ₆ O) _r H The reverse type propylene oxide ethylene oxide block copolymer represented by (II) is mentioned, and any of these can be used in the present invention. Here, k to r represent the same or different integers. In the present invention, a propylene oxide / ethylene oxide block copolymer other than those represented by the above general formula may be used as long as the object of the present invention can be achieved.

The propylene oxide / ethylene oxide copolymer represented by the above general formula (I) or (II) has a solubility of a surfactant in a developer depending on the degree of polymerization (molecular weight) of polypropylene oxide and polyethylene oxide. The foaming property of the developer, the wettability of the resist surface, and the like are affected. The effects of these properties vary depending on the amount of the surfactant added. For example, when the addition amount is about 100 ppm, in the copolymer represented by the general formula (I),
In general, those having a molecular weight of polypropylene oxide of 900 to 3500 and a proportion of polyethylene oxide of 10 to 30% by weight in the copolymer give preferable results. If the molecular weight of the polypropylene oxide in the copolymer is less than 900, the wettability to the resist is poor,
On the other hand, if the molecular weight exceeds 3500, the solubility in the developing solution becomes poor. When the amount of polyethylene oxide in the copolymer is less than 10% by weight in the copolymer, problems such as solubility in a developer and wettability occur. When the amount exceeds 30% by weight, the solubility in the developer is increased. Although the properties are good, problems occur in the defoaming property, and problems occur in any of development uniformity, residual film properties, resist properties, resist pattern shape, sensitivity, and minimum developer amount, which is not preferable. Also, in the reverse type represented by the general formula (II), it is considered that the polyethylene oxide is located at the center of the molecule, but the polyethylene oxide content in the molecule is further higher than that of the normal type. At most, for example, 50p
In the case of pm, even when it is 50% by weight or more, the defoaming property is good, and a favorable result can be obtained. In addition,
The reverse type propylene oxide / ethylene oxide copolymer also has a feature that the chemical resistance is superior to that of the normal type. In any case,
The molecular weight of polypropylene oxide and the content ratio of polyethylene oxide in the copolymer may be appropriately selected depending on the amount of the copolymer added so as to obtain an optimum result.

The amount of the surfactant added is 10 to
When the addition amount is 500 ppm, a developer satisfying the above characteristics can be obtained.
pm is preferred.

Further, the developing solution of the present invention contains additives such as a wetting agent, a stabilizer, a dissolution aid, a residual film or an anti-scum agent which are conventionally known to be used in a developing solution for resist. It can be used as appropriate. Examples of these additives include nonionics, anionics, cationic surfactants, monohydric alcohols, polyhydroxy compounds, and the like other than the propylene oxide ethylene oxide block copolymer surfactant.

The developer of the present invention can be applied to any of the conventionally known positive and negative photoresists, and can be particularly preferably used for positive photoresists. Representative examples of the photoresist to which the developer of the present invention can be applied include, as a positive type, a composition containing an alkali-soluble resin such as a novolak resin and a quinonediazide-based photosensitizer, a chemically amplified resist, and the like. As the negative type, a compound containing a polymer compound having a photosensitive group such as polyvinyl cinnamate, a compound containing an aromatic azide compound, or an azide compound-containing composition comprising a cyclized rubber and a bisazide compound, a diazo compound, Examples thereof include those using a resin, a photopolymerizable composition containing an addition-polymerizable unsaturated compound, and a chemically amplified negative resist.

The developing solution of the present invention can be used in any of the conventionally known developing methods. In particular, when the developing solution is used in a paddle developing method, a static developing method, etc., the improved properties are obtained. Is preferred.

[0020]

The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. In addition, in the following, all% represent weight%.

Examples 1 to 11 Tetramethylammonium hydroxide (TMAH) was dissolved in pure water to a concentration of 2.38%, and the molecular weight of the polypropylene oxide in the copolymer and the ethylene oxide A developer was prepared by adding 100 ppm of a propylene oxide ethylene oxide block copolymer (normal type) having a content ratio shown in Table 1.

The surface tension, foamability, turbidity,
A test was performed on the relative sensitivity of the resist, the resist shape after development, the exposure margin, and the development uniformity under the following conditions, and the developer was evaluated. The results shown in Table 1 were obtained.

(Preparation of resist film sample) The sample used for the evaluation of the developing solution is a positive type photoresist AZ-7800 (manufactured by Hoechst) which basically comprises a naphthoquinonediazide-based photosensitive agent and a novolak resin as a resist. And spin-coated on a HMDS-treated 6-inch silicon wafer substrate so that the film thickness after pre-baking becomes 1.07 μm, and baked on a hot plate at 90 ° C. for 60 seconds to obtain an NA of 0.50. Exposure was performed using a line stepper and post-exposure baked (PEB) on a hot plate at 110 ° C. for 60 seconds.

(Development conditions and post-development processing) In the development, the sample was processed by paddle development at 23 ° C. for 60 seconds, followed by rinsing with pure water and spin drying.
The amount of the developer used was 15 mL.

(Surface Tension) The surface tension of the developer sample was measured using a surface tension measuring device (manufactured by Kyowa Interface Science Co., Ltd.).
It was measured under standard conditions.

(Foaming and defoaming properties) The developer was shaken under the same conditions and allowed to stand, and the state of foaming and defoaming properties were visually observed.

(Turbidity) A surfactant is added to the developer,
The transparency at 0 ° C. was visually observed.

(Resist Relative Sensitivity) Exposure energy when the resist in an exposure area of about 1 cm square (exposed without passing through a reticle) is completely dissolved is _defined as sensitivity (E _th ). With the sensitivity of 100,
Expressed as a relative ratio.

(Resist Shape) The cross-sectional shape of the resist after spin drying was observed with a scanning electron microscope (SEM).

(Exposure Margin) After exposing the resist through a reticle and performing PEB and development, 0.50 μm
The pattern of m is observed by SEM, and the dimensions are measured. 0.
The exposure margin was determined by the numerical value obtained by dividing the exposure amount (E _op ) at the time when the size of 50 μm was obtained by E _th . At this time, those having a numerical value exceeding 1.5 were judged as "good".

(Development Uniformity) The development finish (state of development unevenness of the entire wafer) when the entire surface of the wafer was exposed with an exposure amount of _Eth- 5% _Eth was visually observed.

Comparative Examples 1 to 7 As a developing solution, a developing solution containing no surfactant (Comparative Example 1) or a propylene oxide / ethylene oxide block copolymer (normal type) described in Comparative Examples 2 to 7 in Table 1 was used. Tests were performed in the same manner as in Examples 1 to 11, except that a developer obtained by adding 100 ppm was used, and the results described in Table 1 were obtained.

In the following table, ○ indicates good,
Δ indicates a little inferior but usable, and X indicates a defect. In the table below, “PO molecular weight” is the molecular weight of polypropylene oxide in the copolymer, and “EO content” is the content ratio of ethylene oxide in the copolymer.

[0034]

[Table 1]

Comparative Example 1 did not contain a surfactant, so the surface tension was high, the wettability to the resist surface was poor, and when the developer was used at 15 mL, the developer spread evenly over the entire surface of the 6-inch wafer. The result was inferior in uniformity of development because, for example, the development time could not be strictly controlled even if the development time was not uniform.

In the cases where "turbidity" is indicated by "x" in the table (Comparative Examples 5 and 6), undissolved substances causing turbidity are present in the developing solution, and this is a residue of development or a pattern defect. Because of the cause, it cannot be used as a developer without conducting a test.

For this reason, the test for each characteristic was not particularly performed for those in which "turbidity" in the table was indicated as "x".

Further, in the case where "foaming property, defoaming property" in the table is "x" (Comparative Examples 2, 3, 4, and 7), bubbles exist between the resist surface and the developing solution. However, since the bubbles did not disappear immediately, the resist in that portion was not developed, or the development time was different from other portions, resulting in poor development uniformity.

Examples 12 to 16 As a developing solution, tetramethylammonium hydroxide (TM
AH) in pure water containing 2.38% of propylene oxide ethylene oxide block copolymer (normal type) in which the molecular weight of polypropylene oxide in the copolymer is 1750 and the content of polyethylene oxide is 20%. Tests were performed in the same manner as in Examples 1 to 11, except that the addition was performed in the amount described in Table 2, and the results described in Table 2 were obtained.

Comparative Examples 8 and 9 The amount of the surfactant added was 1000 ppm (Comparative Example 8).
Example 12 except that it was 000 ppm (Comparative Example 9).
Tests were conducted in the same manner as in Examples 1 to 11 using the same developing solutions as in Examples 1 to 16, and the results shown in Table 2 were obtained.

[0041]

[Table 2]

With respect to those in which "turbidity" is indicated by "x" in the table (Comparative Examples 8 and 9), the test for each characteristic was not particularly performed for the same reason as in Comparative Examples 5 and 6.

Examples 17 and 18 Tetramethylammonium hydroxide (TMAH) was dissolved in pure water to a concentration of 2.38%.
The propylene oxide ethylene oxide block copolymer (reverse type) described in (1) was added at 50 ppm to prepare developers of Examples 17 and 18. Using this developer, a test was conducted in the same manner as in Examples 1 to 11, and the results shown in Table 3 were obtained.

[0044]

[Table 3]

As is clear from the above Examples and Comparative Examples, the developer of the present invention satisfies various characteristics conventionally required for a resist developer by adding a small amount of a surfactant. It can be seen that can be obtained. In addition, the surface tension of the developer of the present invention is remarkably improved and the wettability of the developer with respect to the resist film is improved as compared with the developer without the surfactant. It was found that the amount of the developer used was about 1/3 of that in the case of using a developer containing no surfactant.

[0046]

As described above, the developing solution for a photoresist of the present invention has no bubble generation, and even if bubbles are generated, quickly defoams, and has a solubility of surfactant, uniformity of development, and This has the effect that the amount of developer used can be reduced while maintaining the remaining film characteristics, the resist pattern shape, and the sensitivity well.

Claims (5)

[Claims] A propylene oxide / ethylene oxide block copolymer surfactant is added to a resist developer mainly containing an organic base containing no metal ion.
A resist developing solution characterized by adding ppm. 2. The propylene oxide / ethylene oxide block copolymer surfactant of the following general formula (I):
2. The resist developer according to claim 1, which is a propylene oxide ethylene oxide block copolymer represented by the formula: General formula _{(I) HO (C 2 H} 4 O) k - (C 3 H 6 O) m - (C 2 H 4
O) _n H ( _where k, m, and n represent the same or different integers, respectively) 3. The propylene oxide / ethylene oxide block copolymer surfactant according to the following general formula (II):
2. The resist developer according to claim 1, which is a propylene oxide ethylene oxide block copolymer represented by the formula: Formula _{(II) HO (C 3 H} 6 O) p - (C 2 H 4 O) q - (C 3 H 6
O) _r H (where p, q, and r represent the same or different integers, respectively) 4. The polypropylene oxide in the propylene oxide / ethylene oxide block copolymer represented by the above general formula (I) has a molecular weight of 900 to 3500 and a polyethylene oxide ratio of 10 to 30.
3. The developing solution for a resist according to claim 2, wherein the amount is% by weight. 5. The method according to claim 1, wherein the resist developing solution is a positive resist developing solution.
Item 6. The resist developer according to item 1.