JPH0342664A - Radiation sensitive resist - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a positive type resist used for forming fine patterns of semiconductor devices such as VLSIs, which is sensitive to radiation and exhibits good characteristics. Regarding resist.

[Prior Art] Amid the demand for higher integration of semiconductor devices, development of microfabrication technology at the submicron level is progressing. In order to realize this technology, several methods are being considered, but among them, shortening the wavelength of the light source used in optical lithography technology, and using negligible electron beams and X-rays as exposure sources due to problems such as optical interference. High-energy radiation exposure technology, such as those used in

Conventionally, resists made of novolak resin and naphthoquinone azide have been known as resists for photolithography, and these resists have excellent properties such as high resolution, dry etching resistance, and high sensitivity.

However, as the wavelength of the exposure source becomes shorter, the aforementioned novolac resin type suffers from incompatibility of the sensitive wavelength, a drastic decrease in sensitivity due to a decrease in the radiation transmittance of the resist itself, and defects in the shape of the resist batten. A problem occurs.

Furthermore, as resists for electron beams and X-rays, positive resists such as polymethacrylate resins and polyolefin sulfone resins, and negative resists such as chloromethylated polystyrene have been developed.

However, the former has disadvantages such as low dry etching resistance and low sensitivity, and the latter has disadvantages such as a decrease in resolution due to swelling by the developer.

Furthermore, JP-A No. 175046 discloses that an alkali-soluble phenol resin is resistant to alkali dissolution before exposure, but becomes alkali-soluble when exposed to radiation. Compositions with radiation-sensitive onium salts are disclosed. In addition, special public relations
Publication No. 3-59131 discloses a composition of an alkali-soluble polymer compound and an alkali-insoluble organic acid ester that produces an acid before esterification upon irradiation with high-energy radiation. The purpose of both methods is to obtain a highly sensitive resist. However, although the compositions disclosed in these publications have shown some improvement in various properties, they have not been able to improve them to a practical level.

On the other hand, in order to compensate for the shortcomings of resists, studies are being conducted to improve the process of using resists.
A thick planarized organic layer is formed on a semiconductor substrate, several thin films and a resist layer are formed on top of this, and the resist pattern of the upper layer is sequentially transferred to the lower layer by dry etching to form a resist with a high aspect ratio. Multilayer processes have been developed to form patterns.

However, the multilayer method has the disadvantage that dry etching must be performed several times in order to transfer the resist pattern, and extremely complicated steps and treatments must be performed.

[Problems to be Solved by the Invention] The present invention has been made to solve the problems of the prior art as described above, and has high sensitivity to radiation exposure and the ability to faithfully expose only the exposed portion to alkali. The object of the present invention is to provide a positive radiation-sensitive resist that has submicron-level resolution as a result of solubilization and has high dry etching resistance that can be used as a single layer.

[Means for Solving the Problems] As a result of intensive research aimed at achieving the above object, the present inventors found that the general formula (■): (wherein R1 is a bisimino group, a phenylene group, a biphenylene group, (However, the hydrogen atoms of R1 and R2 may be substituted with a substituent that does not participate in the reaction), x represents either 10--CH2--8O2--NHCO-1-CO- , n is a positive integer), an alkali-soluble polymer compound, and a compound that generates an acid when irradiated with radiation, is suitable for use as a radiation-sensitive resist. The present invention was completed based on the discovery that this material has unique characteristics.

[Function] In the present invention, an alkali-soluble polymer compound interacts with the polymer represented by the general formula (1) and becomes insoluble in an aqueous alkaline solution. However, when irradiated with radiation, the interaction between these molecules is canceled due to the effect of the acid generated from the coexisting compounds that generate acid when exposed to radiation, and the irradiated area becomes alkaline. It becomes soluble, and as a result, positive pattern formation becomes possible. The generation of acid is essential to release the interactions between molecules, and this reaction is further accelerated by adding a heating step. Furthermore, the main chain of the polymer represented by general formula (I) is partially cleaved under the influence of the generated acid. Since these two effects are enhanced by the heating process, the resist of the present invention achieves a greater sensitivity improvement than when using conventional resists.

[Example] General methods for synthesizing the polymer represented by the general formula ()) used in the present invention include (11) a method of directly esterifying a dioxime compound or a diphenol compound with a dicarboxylic acid, (2) There are methods such as a method of low-temperature polycondensation of a dioxime compound or diphenol compound and a dicarboxylic acid halide, and (3) a method of transesterification of a dioxime compound or diphenol compound and a dicarboxylic acid ester. Among these methods, ( 2)
The method of polycondensation at a low temperature is the most preferable because it has advantages such as low reaction temperature so that side reactions do not occur, the reaction ratio is easy to control, and the molecular weight is easy to control. The reaction in this case is generally carried out in the temperature range from -5 to 10°C.

It is preferable that n in the general formula (1) is in the range of 5 to 500, particularly in the range of 10 to (00).

Examples of dioxime compounds that can be used to synthesize the polymer represented by general formula (1) include glyoxime, dimethylglyoxime, diethylglyoxime, dibutylglyoxime, diphenylglyoxime, cyclohexanedionedioxime, benzoquinonedioxime, etc. can be given.

In addition, diphenol compounds include catechol, resorcinol, hydroquinone, dihydroxybiphenyl,
Examples include dihydroxydiphenyl ether, dihydroxydiphenylmethane, dihydroxydiphenylsulfone, dihydroxydiphenylamide, dihydroxybenzophenone, bisphenol A, and the like.

Examples of dicarboxylic acids that can be used in the direct esterification include oxalic acid, malonic acid, maleic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexyl dicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenyl ether dicarboxylic acid, and naphthalene dicarboxylic acid. etc. can be given.

In addition, dicarboxylic acid chlorides, preferably dicarboxylic acid chlorides, used in the case of low-temperature polycondensation with dicarboxylic acid halides include, for example, oxalic acid dichloride, malonic acid dichloride, succinic acid dichloride, glutaric acid dichloride, adipic acid dichloride,
Pimelic acid dichloride, superic acid dichloride, sebacic acid dichloride, maleic acid dichloride, fumaric acid dichloride, cyclohexanedicarboxylic acid dichloride, phthalic acid dichloride, isophthalic acid dichloride, terephthalic acid dichloride, biphenyl dicarboxylic acid dichloride, diphenylmethane dicarboxylic acid dichloride, diphenylsulfone dicarboxylic acid dichloride Examples include acid dichloride, penzanilide docarboxylic acid dichloride, and benzophenone dicarboxylic acid dichloride. Furthermore, in the case of transesterification, dicarboxylic acid esters such as isophthalic acid diphenyl ester can be used.

The alkali-soluble polymer compound used in the present invention is
Since the resulting radiation-sensitive resist is used as a radiation-sensitive resist, and is mainly used as a single-layer resist, it is preferable to have a structure with excellent dry etching resistance.

Examples of such alkali-soluble polymer compounds include phenol novolac resin, cresol novolac resin, naphthol novolac resin, p-vinylphenol resin, and the like. The average molecular weight of these is preferably about 2,000 to 50,000.

The radiation includes X-rays, electron beams, LIV, D
It is described as a concept that also includes UV light.

Another component used in the present invention, a compound that generates an acid upon irradiation with radiation, includes, for example, triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluorophosphate, and triphenylsulfonium hexafluorophosphate. Alsinate, triphenylsulfonium hexafluorophosphate, triphenylsulfonium trifluorosulfonate, diphenyliodonium tetrafluoroborate, diphenyliodonium hexafluoroantimonate, diphenyliodonium hexafluoroarsinate, diphenyliodonium hexafluorophosphate -2,4
, B-) Lis(trichloromethyl)triazine, 2-aryl-4,6-bis(trichloromethyl)triazine, α,α,α,-tribromomethyl-phenylsulfone, α,α,α.

α゛、α、α゛hexachloroxylylene, 1 methyl sulfonic acid-2-nitrobenzyl ester, 2-2 l acetic acid
- Examples include lobenzyl ester.

The resist of the present invention is obtained by blending the three components described above, and the content of each component is 5 to 60% (by weight, the same applies hereinafter) of the compound represented by the general formula (I); Preferably 10 to 40%, alkali-soluble polymer compound 40
Appropriate ranges are 94% to 94%, preferably 60 to 90%, and 0.05 to 20%, preferably 0.5 to 10% of compounds that generate acid upon irradiation with radiation. If the amount of the polymer represented by general formula (1) is less than 5%, patterning tends to be difficult, and if it exceeds 60%, the amount of alkali-soluble polymer compound decreases, resulting in poor dry etching resistance. A downward trend occurs. If the acid-generating compound is less than 0.05%, it will be difficult to form a good pattern, and if it exceeds 20%, it will be difficult to achieve uniform compatibility of the three components, so the pattern formed will be difficult. defects are more likely to occur.

The resist of the present invention is composed of three components as described above, and two agents (for example, aminosilane, aminoalkoxysilane, alkylalkoxysilane, etc.) are used to improve the adhesion between the substrate and the resist. In addition, other compounds suitable for the purpose can be added as necessary.

A solvent may be added to the resist of the present invention for viscosity adjustment, etc., and any solvent can be used as long as it dissolves the above three components and does not react with these components. Common examples include methyl cellosolve, ethyl cellosolve, dimethyl glyme, diethyl glyme, cyclopentanone, cyclohexanone, γ-butyrolactone, and isoamyl acetate.

When a resist solution is prepared using the resist of the present invention and a solvent in combination, the solution is applied onto a substrate such as a silicon wafer, prebaked, and exposed to UV light and deep
After irradiation with radiation such as UV light, X-rays, and electron beams, 8
Pattern formation can be carried out by a general method of heating at about 0 to 150° C. for 5 to 30 minutes and then developing.

As the resist developer, an aqueous solution of ammonia, triethylamine, dimethylaminoethanol, tetramethylammonium hydroxide, sodium hydroxide, sodium carbonate, or the like can be used.

The resist of the present invention will be described below with reference to specific examples, but the present invention is not limited to these examples.

Example 1 8.8 g (0.1 mol) of glyoxime, 20.2 g of triethylamine, and 1 g of dioxane IO were mixed and cooled with water.

15.5 g (0.1 mol) of succinic acid chloride was added dropwise to this solution. After the dropwise addition, the reaction was continued at room temperature for 4 hours.

After the reaction, the reactants are poured into a large excess of water containing ice,
Thorough cleaning was performed. Finally, after washing with MetaTsuru, it was dried under reduced pressure to obtain Polymer 1. The infrared absorption spectrum of this product showed absorption at <1,750 cm' due to the ester bond. Also, the molecular weight was measured by GPC and was 3,000.
It was found that the molecular weight of

4 Next, p-vinylphenol polymer (Mn = 5,70
0) and 2 g of the above polymer were dissolved in 40 g of diglyme, and diphenyliodonium tetrafluoroborate (abbreviated as DITFB) was further added as an acid generator.
0.5g was added to form a solution. This solution was filtered through a 0.2 m filter to prepare a resist solution.

This resist solution was applied onto a silicon wafer using a spin coater with a rotation speed of 3,000 rpm.
Pre-cure in an oven for 20 minutes. The sample was cooled to room temperature and exposed to 250 nm Deep UV light for approximately 1
Exposure was performed at 0 mj/cJ. After exposure, it was heated in ozone at 100° C. for 10 minutes, then cooled to room temperature, and immediately immersed in a 2% aqueous tetramethylammonium hydroxide solution for 3 minutes.

By this operation, a good pattern with 0.35 AIm lines and spaces was obtained. This pattern was then dried at 100° C. for 30 minutes and then OFed using a counter electrode type plasma etching device.

Plasma etching in gas was performed. the result,
It was found that it had the same resistance to de5 writing as 0FPR800 (manufactured by Tokyo Ohka Kogyo ■).

Example 2 11.0 g (0.1 mol) of resorcin, 16 pyridine
g.

120 g of cyclopentanone was mixed and cooled on ice. This solution isophthalic acid chloride 20.3g (0.1 mol)
was added as a solid in several batches. 4 at room temperature after adding
The reaction continued for hours.

After the reaction, the solution was filtered to remove crystals, and the filtrate was poured into a large excess of methanol to precipitate the polymer. After thorough washing with methanol and water, the product was dried under reduced pressure to obtain Polymer 2. The average molecular weight of this product was about 2.000.

Next, 7 g of p-vinylphenol, 3 g of the above polymer,
A resist solution was obtained in the same manner as in Example 1 using 0.5 g of DITFB and 0.5 g of DITFB.

Further, patterning was performed in the same manner as in Example 1. However, the exposure amount was 15 mj/cJ, and a line and space pattern of 0°4 addition was obtained.

Examples 3 to 19 Using the compounds shown in Table 1, polymer 3.5 was obtained according to Method 6 of Example 1, and polymer 4.6.7 was obtained according to the method of Example 2. Using these polymers 3 to 7,
A resist solution having the composition shown in Table 2 was prepared in the same manner as in Example 1.

Sensitivity, resolution, and dry etching resistance of the prepared resist were evaluated in the same manner as in Example 1.

The results are shown in Table 2.

The abbreviations in Table 2 are as follows.

Alkali-soluble polymer compound PvP Paravinylphenol CN Cresol novolak resin Mn = 800
0 Acid generator DITPB Diphenyliodonium tetrafluoroborate TPSPA) Liphenylsulfonium hexafluoroantimonate TCMT 2-phenyl-4,6-bis(trichloromethyl)triazine exposure Exposure from Example 3 to Example 13 was 250 nm Exposure in Examples 14 to 19 was performed using a 20 KeV electron beam using Deep UV light.

From the results in Table 2, the resist of the present invention can be used as an exposure source of D
eep It was found that the resist of the present invention has high sensitivity and high resolution without reducing the plasma etching speed when using either UV light or electron beam. [Effects of the Invention] The resist of the present invention can be used as a radiation-sensitive resist. It is extremely useful and can be effectively used in the manufacture of semiconductor devices that require ultra-fine patterns. Further, by using the resist of the present invention, high resolution patterning can be performed without reducing dry etching resistance.

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Claims (1)

[Claims] (1) General formula (I): ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, R_1 is a bisimino group, phenylene group, biphenylene group, ▲There are mathematical formulas, chemical formulas, tables, etc.), R_2 represents an alkylene group, phenylene group, biphenylene group, ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, the hydrogen atoms of R_1 and R_2 may be substituted with substituents that do not participate in the reaction), and X is -O-, -CH_2-, -SO_2-, -NHCO-,
-CO-, n is a positive integer); an alkali-soluble polymer compound; and a compound that generates an acid when irradiated with radiation.