JPH02273641A - Triphenylmethane derivative and its production - Google Patents

Abstract

NEW MATERIAL:A triphenylmethane derivative expressed by the chemical structure. USE:The derivative expressed by the formula has excellent sensitivity, resolving power and heat resistance and is used as an additive of positive type radiation sensitive resist composition. PREPARATION:4-Carboxylbenzaldehyde is subjected to condensation reaction with 2,5-xylenol of 2.0 to 5.0mol based on 1mol of 4-carboxy-benzaldehyde in a solvent such as water in the presence of a catalyst, e.g. 20% concentrated hydrochloric acid, having molar ratio of 1.0 to 10 based on 1mol to 4- carboxybenzaldehyde at 50 to 60 deg.C for 3 to 5 day and metal ion of the resultant condensation product is removed and then purified by recrystallization to provide the compound expressed by the chemical structure.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a triphenylmethane derivative and a method for producing the same.

<Conventional technology> Positive photoresists utilize their high resolution to produce f! Etching protection of photo-etching method when manufacturing integrated circuits such as A-clad laminates, ICs and LSIs 11! I
It is used as.

As for integrated circuits, miniaturization has progressed due to higher integration, and submicron pattern formation is now required, and positive photoresists with excellent resolution are required. Conventionally, a mask contact method has been used to form integrated circuits, but it is said that the limit of this method is 2 μm, and instead, a reduction projection exposure method is attracting attention. In this method, the pattern of a master mask (reticle) is reduced and projected using a lens system for exposure, and resolution is possible down to submicrons.However, one of the problems with Jin's reduction projection exposure method is the throughput. In other words, unlike a batch exposure method such as the conventional mask contact method, the reduction projection exposure method involves repeated exposure in divisions, resulting in a longer total exposure time per wafer. .

The most important way to solve this problem is to improve the sensitivity of the resist used, as well as improving the equipment. If exposure time can be shortened by increasing sensitivity, throughput and yield can be improved. On the other hand, L.S.
As the integration degree of I increases, the width of wiring becomes finer, and therefore dry etching has become mainstream instead of conventional wet etching.

Because of this dry etching, heat resistance of the resist has become more required than before.

Looking at the positive photoresists currently used from this point of view, they are not necessarily satisfactory in terms of sensitivity, resolution, and heat resistance. Generally, positive photoresists have lower sensitivity than negative photoresists, and improvements are desired.

For example, the simplest way to achieve high sensitivity is to lower the molecular weight of the novolak resin used in positive photoresists, which increases the rate of dissolution in alkaline developers and apparently increases the sensitivity of the resist. However, with this method, film loss in non-exposed areas increases (so-called decrease in film remaining rate), pattern shape deteriorates, and the difference in dissolution rate in developer between exposed and non-exposed areas becomes small. The so-called r value decreases (resolution decreases).
In addition to these problems, there arises an extremely serious inconvenience in that the heat resistance of the resist decreases.

That is, at present, there is no positive resist that has all of sensitivity, resolution, and heat resistance, and we are in an extremely disadvantageous situation in which an attempt to improve one of these results in further deterioration of the other.

<Problems to be Solved by the Invention> An object of the present invention is to provide a positive radiation-sensitive resist composition for use in the production of integrated circuits that solves the problems of the prior art and has excellent sensitivity, resolution, and heat resistance. It is an object of the present invention to provide a triphenylmethane derivative that can be added to produce a triphenylmethane derivative.

<Means for Solving the Problems> As a result of intensive studies, the present inventors have found that the above problems can be solved by adding a compound represented by the following formula (1) to a positive radiation-sensitive composition. Heading: The present invention has been completed.

The compound of the present invention can be synthesized by a condensation reaction of 2,6-xylenol and 4-carboxybenzaldehyde.

In addition, examples of the acid catalyst used in the condensation reaction include organic acids, inorganic acids, divalent metal salts, and the like. Specific examples include oxalic acid, hydrochloric acid, sulfuric acid, perchloric acid, p-toluenesulfonic acid, trichloroacetic acid, phosphoric acid, formic acid, zinc acetate, zinc chloride, magnesium acetate, etc.
Hydrochloric acid is preferred.

The molar ratio of charging is 4-carboxybenzaldehyde 1
In terms of mole, 2.6-xylenol is 2.0 to 5.0
mol, preferably 8.0 to 4.0 mol.

The appropriate amount of catalyst is 1.0 to 10 in molar ratio to 4-carboxybenzaldehyde.

Hydrochloric acid can be diluted to 5 to 85% depending on the reaction temperature and reaction time, but if the concentration is low, the reaction mass becomes lump-like and difficult to stir, so it is diluted by 20 to 85%.
5% is preferred.

When using 20% hydrochloric acid, the binding reaction is carried out at 50-60°C.
, is carried out in 8 to 5 hours. If it is 20% or more, it is necessary to lower the reaction temperature or shorten the reaction time, and if it is less than 20%, it is necessary to raise the reaction temperature or shorten the reaction time.

Examples of the diluting solvent include water, toluene, xylene, and cyclohexane, with water being preferred.

The condensation product can be purified by recrystallization after demetallization.

Demetallization can be carried out by dissolving the product in an organic solvent that is separated by mixing it with water, and washing with ion-exchanged water. Examples of the organic solvent include methyl isobutyl ketone, ethyl cellosolve acetate, ethyl acetate, and the like.

The positive radiation-sensitive resist composition using the present invention contains an alkali-soluble resin and a 12-quinonediazide compound in addition to the triphenylmethane derivative represented by formula 0).

Examples of the alkali-soluble resin include polyvinylphenol and alkali-soluble novolak resin.

As the 1.2-quinonediazide compound, 1°2-naphthoquinonediazide-5-sulfonic acid ester or the like is used.

Preparation of a positive radiation-sensitive resist composition is performed in 1.2 above.
- A quinonediazide compound and an alkali-soluble resin containing a triphenylmethane derivative of the formula (R) are mixed and dissolved in a suitable solvent such as ethyl cellosolve acetate.

Regarding the content of the triphenylmethane derivative in the resist composition, it is preferably 4 to 70 parts by weight, more preferably 10 to 70 parts by weight, based on 100 parts of the total amount of the triphenylmethane derivative and the alkali-soluble resin. It is 40 parts by weight.

<Effects of the Invention> The radiation-sensitive resist composition using the compound of the present invention has the following properties:
Superior sensitivity and resolution compared to existing resist compositions,
It has improved heat resistance.

<Examples> Next, the present invention will be explained in more detail with reference to practical examples, but the present invention is not limited to these examples in any way.

Example 1 2.6-xylenol 29.8 F, 4-
Carboxypenzcaldehyde9. Of, 20% hydrochloric acid 10
0f was charged and reacted for 4 hours at 60 to 60°C with stirring in a water trough.
゜The crude cake obtained by filtering the reaction mixture at room temperature was
0? Dissolve in ethyl acetate and add 600ml of ion-exchanged water. After extraction, the ethyl acetate layer was washed 8 times with 50 of ion-exchanged water. The substance obtained by concentrating this was washed 8 times with toluene 101' in a bulb, filtered, and dried to obtain purified cake 18.9F. Yield 59
．． 4% (based on 4-carboxybenzaldehyde) It was confirmed by the mass spectrum, 'HNMR spectrum and melting point that this was a compound having the structure of the following formula (1).

Mass spectrum rn//e a7a (M+) to HNMRx';l tor (solvent: acetone d6TMs
) Chemical shift value δ (ppm): 11.1 (broad, IH),
7.97 (d, 2H) 7.91 (s, 2H) , 7.1
8(d, 2H), 6.68(s, 2H).

6.46 (s, 2H), 5.64 (s, 1fl), 2.
04 (s, 12H) Melting point 190-191°C Synthesis example 1 Metacresol 149? , para-cresol 121F, ethyl cellosolve acetate 2525', and 5% aqueous formalin solution (87.0%) 147.81 were added dropwise over 40 minutes with stirring, and the mixture was further reacted with stirring for 7 hours. Thereafter, the mixture was neutralized, washed with water, and dehydrated to obtain a solution of novolak resin in ethyl cellosolve acetate. The weight average molecular weight in terms of polystyrene determined by GPC was 9,600.

Synthesis Example 2 Ethyl cellosolve acetate solution of the novolac resin obtained in Synthesis Example 1 (novolac resin content 41.2'%)
) 120f was placed in a bottomless separable flask (No. 81), ethyl cellosolve acetate 868.8F and n-heptane 544.6F were added, and after stirring at 20°C for 80 minutes, the mixture was allowed to stand still and separated. Normal heptane in the lower layer obtained by liquid separation was removed using an evaporator to obtain a solution of novolak resin in ethyl cellosolve acetate. G
Polystyrene equivalent weight average molecular weight by PC is 1660
It was G.

Reference Examples 1 to 2 and Comparative Examples 1 to 2 The combined product obtained in Example 1 and the novolac resin obtained in Synthesis Example 1゜2 were each mixed with ethyl heptalosolve acetate in the composition shown in Table 1 together with a photosensitizer. A resist solution was prepared. The amount of solvent was adjusted to give a film thickness of 1.28 μm under the coating conditions shown below. Each of these compositions was filtered through a 0.2 μm Teflon filter to prepare a resist solution. This was coated at 400 Or, p, m using a spin coating machine onto a silicon wafer which had been cleaned by a conventional method. Next, this silicon wafer was baked for 1 minute on a vacuum suction type hot plate at 100"C. Thereafter, it was exposed to heat using a reduction projection exposure apparatus (NA=0.28) using an 8fSOW ultra-high pressure mercury lamp as a light source. Exposure was carried out by changing the exposure time step by step.Then, developer solution 30PD (
It was developed using Sumitomo Chemical Co., Ltd. (trade name).

After rinsing and drying, the film loss and exposure time of each sheet were plotted to determine the sensitivity. Further, the remaining film rate was determined from the remaining film thickness of the unexposed area.

In addition, silicon wafers with resist patterns after development were placed in a clean oven set at various temperatures for 80 minutes.
The resist pattern was left in an air atmosphere for 1 minute, and then the resist pattern was observed with a scanning electron microscope to evaluate heat resistance.

These results are summarized in Table-1. As is clear from Table 1, it was recognized that the balance of sensitivity, resolution, and heat resistance of the Examples was significantly improved compared to that of the Comparative Examples.

Table 1

[Brief explanation of drawings]

FIG. 1 is a °H nuclear magnetic resonance spectrum of the compound of Example 1. (Margin below)

Claims (2)

[Claims] (1) Triphenylmethane derivative represented by the following formula (I)▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (2) A method for producing the compound according to claim 1, which comprises reacting 2,5-xylenol and 4-carboxybenzaldehyde in the presence of an acid catalyst.