JPH04340553A - Laminated material for multilayer resist method - Google Patents

Abstract

PURPOSE:To form a high-precision mask pattern on a substrate by multilayer resist method by using a uniform and dense silicon oxide film as an intermediate film formed under nonaqueous condition. CONSTITUTION:A mask pattern is formed on a substrate to be worked by multilyaer resist method that a flattening film, intermediate film, and resist film are successively formed on the substrate or an intermediate film and resist film are successively formed on the substrate and then a desired pattern is transferred successively from the upper layer. In this method, a silicon oxide film formed under nonaqueous condition is used as the intermediate film.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated material for use in forming a mask pattern by a multilayer resist method. More specifically, the present invention relates to a laminated material for use in a two-layer or three-layer resist method, which is used in the manufacturing process of semiconductor devices and can transfer a resist pattern onto a processed substrate with high precision. .

0002

2. Description of the Related Art In recent years, as the degree of integration of semiconductor devices has increased, there has been a demand for finer resist patterns in lithography processes. A multilayer resist method has been proposed as one means to meet this demand. Three-layer resist method and two-layer resist method are conventionally known as such multilayer resist methods, but in this three-layer resist method, a thick fluid layer is first applied to the substrate in order to flatten the unevenness of the substrate. After forming a flattening film with an organic material, an intermediate film made of an inorganic material is provided on top of the planarization film, and a resist film is further formed on top of the planarization film, which is exposed and developed to form a pattern. The two-layer resist method uses an intermediate film made of an inorganic material that has the effect of flattening the unevenness of the substrate. After forming the
This is carried out by forming a resist film thereon, sequentially etching it in the same way as the three-layer resist method described above, and transferring the resist pattern.

By the way, in order to form the intermediate film in the multilayer resist method, from the viewpoint of mass production, a coating type silica material prepared by hydrolyzing a silicon compound such as an alkoxysilane or a halogenosilane is conventionally used. A method has been used in which an intermediate film made of a silicon oxide film is formed by applying this coating-type silica-based material and then baking it.

However, the silicon oxide film formed in this way has hygroscopic properties and easily absorbs moisture in the atmosphere. Therefore, when a resist pattern is formed on this film, the absorbed moisture will cause damage to the silicon oxide film. There is a drawback that adhesion with the resist pattern is reduced, and sufficient precision cannot be obtained when transferring the resist pattern by etching.

[0005]

[Problems to be Solved by the Invention] The present invention overcomes the drawbacks of the laminated materials used in the conventional multilayer resist method, and provides a method for the multilayer resist method that can transfer a resist pattern onto a processed substrate with high precision. This was done for the purpose of providing a laminated material.

[0006]

[Means for Solving the Problems] The present inventors have conducted extensive research in order to develop a laminated material used to form a mask pattern using a multilayer resist method that can transfer a resist pattern onto a processed substrate with high precision. As a result, the inventors discovered that the above object can be achieved by using a silicon oxide film with low hygroscopicity formed under non-aqueous conditions as the interlayer film, and based on this knowledge, the present invention was completed.

That is, the present invention provides a three-layer resist method having a structure in which a first layer consisting of a flattening film, a second layer consisting of an intermediate film, and a third layer consisting of a resist film are laminated on a substrate to be processed. In the laminated material, the intermediate film is made of a silicon oxide film formed under non-aqueous conditions, or a first layer made of an intermediate film and a second layer made of a resist film are placed on a substrate to be processed.
The present invention provides a laminated material for a two-layer resist method having a structure in which layers are laminated, wherein the intermediate film is a silicon oxide film formed under non-aqueous conditions. be.

[0008] "Non-aqueous conditions" as used in the present invention means conditions in the absence of water and without the production of water. The interlayer film made of silicon oxide film used in the conventional multilayer resist method is formed in the presence of water or under conditions where water is generated, so in its infrared absorption spectrum,
While there is a peak in the wave number range of 3200 to 3600 cm due to the presence of water, the intermediate film made of the silicon oxide film of the present invention has substantially no peak in the wave number range. There is clearly a difference in composition between the two.

[0009] An intermediate film made of a silicon oxide film having such characteristics can be obtained, for example, by applying an organic solvent solution of a silazane compound on the substrate surface or a flattened film, and then baking the solution in an oxidizing atmosphere. It will be done. This silazane compound is a general term for compounds having an Si-N bond in the molecule, but in the method of the present invention, it is preferable to use a silazane compound that does not contain an oxygen atom in the molecule.

Such a silazane compound can be obtained by reacting a halogenosilane or organohalogenosilane with ammonia or an amine in an organic solvent. Examples of the halogenosilane used at this time include S
iCl4, HSiCl3, H2SiCl2, H3SiC
Examples of organohalogenosilanes include CH3SiHCl2, CH3S
iH2Cl, CH3SiCl3, (CH3)2SiCl
2, (CH3)3SiCl, C2H5SiCl3, (C
2H5)3SiCl, (C2H5)(C6H5)SiC
l2, (C2H5) (C6H5)2SiCl, (CH3
)3CSiHCl2, (CH3)2CHSiHCl2,
(C6H5)SiHCl2, (C6H5)SiCl3,
(C6H5)2SiCl2, (C6H5)3SiCl,
C6H5CH2SiCl3, (C6H5CH2)2Si
Examples include Cl2, (C6H5CH2)3SiCl, and the like.

On the other hand, examples of amines to be reacted with these halogenosilanes and organohalogenosilanes include lower alkylamines such as monomethylamine, ethylamine, propylamine, and butylamine, polyamines such as ethylenediamine, and aralkylamines such as benzylamine and phenethylamine. etc. can be mentioned.

[0012] Examples of organic solvents used in these reactions include toluene, xylene, diethyl ether,
Examples include dichloromethane.

Particularly suitable silazane compounds include HSiCl3, H2SiCl2, H3SiCl2,
It is obtained by dissolving halogenosilane such as and blowing ammonia gas into it.

In the present invention, the reaction mixture of halogenosilane or organohalogenosilane and ammonia or amines thus obtained can be used as a coating liquid as it is, or the reaction mixture can be distilled under reduced pressure or the like. After removing the solvent and recovering the desired silazane compound as an oily substance or solid substance, this can be dissolved in a suitable organic solvent to prepare a coating solution.

Examples of the organic solvent in this case include methanol, ethanol, propanol, butanol, cyclohexanol, benzyl alcohol, dimethylolbenzene, furfuryl alcohol, tetrahydrofurfuryl alcohol, diacetone alcohol, ethylene glycol monoalkyl ether, and diethylene glycol. Alcohols such as monoalkyl ether, triethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, acetic acid alkyl ester, diethylene glycol monoalkyl ether acetate, triethylene glycol monoalkyl ether acetate,
Propylene glycol monoalkyl ether acetate, acetoacetic acid ethyl ester, lactic acid alkyl ester,
Esters such as benzoic acid alkyl ester, benzyl acetate, glycerin diacetate, ketones such as acetone, methyl ethyl ketone, cyclohexanone, acetylacetone, isophorone, diethyl ketone, methyl isobutyl ketone, methyl n-butyl ketone, acetonyl acetone, n-pentane, Examples include hydrocarbons such as n-hexane, isohexane, n-heptane, n-octane, isooctane, benzene, tonene, xylene, ethylbenzene, diethylbenzene, isopropylbenzene, and tetralin. These organic solvents may be used alone or in combination of two or more.

In the present invention, in order to form the desired intermediate film, 1 to 60% by weight of a silazane compound is added to the coating liquid.
, preferably in a proportion of 10 to 30% by weight, and whose viscosity at room temperature is in the range of 0.5 to 50 centipoise, preferably 1 to 20 centipoise, is practically suitable. The viscosity depends on the desired film thickness, etc.
It can be adjusted by appropriately selecting the type and amount of the organic solvent.

The interlayer film in the present invention can be prepared by applying the coating solution prepared as described above to the surface on which the interlayer film is to be formed using a spinner method.
After coating by a conventionally used method such as a spray method or a dipping method, it is dried at a temperature of about 50 to 200°C to form a polysilazane film, and then coated in the air or an oxygen atmosphere at a temperature of usually 200 to 800°C. The polysilazane film can be formed by baking at a temperature in the range of 15 to 60 minutes to convert the polysilazane film into a silicon oxide film.

The intermediate film thus formed is a crack-free, homogeneous, continuous film made of silicon oxide with low hygroscopicity and has a thickness of 0.2 to 3.0 μm. Nitrogen atoms and carbon atoms may be contained to the extent that they are not included.

In order to form a mask pattern on a substrate by a multilayer resist method using the laminated material of the present invention, in the case of a three-layer resist method, first a flattening layer made of an organic resist, polyimide resin, etc. is formed on the substrate. After forming
forming an intermediate film made of the silicon oxide film thereon;
Further, a resist film is formed on this intermediate film, and then active rays are irradiated through a mask with a predetermined pattern, followed by development treatment, thereby forming a resist pattern on the silicon oxide film. Next, the silicon oxide film is removed by etching using the formed resist pattern as a mask, and then the planarization layer is removed by etching using the patterned silicon oxide film as a mask. In the case of the two-layer resist method, an intermediate film is first formed from the silicon oxide film on the substrate, a resist pattern is formed on it by lithography, and then this resist pattern is used as a mask to The silicon oxide film may be removed by etching.

In this case, in order to improve the adhesion between the silicon oxide film and the resist film formed thereon, the silicon oxide film is heated to a temperature of 200 to 600% immediately before forming the resist film.
The heat treatment is preferably performed at a temperature in the range of 0° C., and if necessary, the surface of the silicon oxide film may be subjected to a known hexamethyldisilazane treatment to improve adhesion to the resist film.

Furthermore, in the present invention, even if the silicon oxide film forming step described above is repeated several times to form a silicon oxide film, a homogeneous continuous film can be obtained. A film can be easily formed.

[0022]

[Effects of the Invention] By using the laminated material of the present invention, a highly accurate mask pattern can be formed on a substrate by using a homogeneous and dense silicon oxide film with low hygroscopicity as an intermediate film in a multilayer resist method. It is possible.

Furthermore, the laminated material of the present invention can form an intermediate film consisting of a thick, homogeneous silicon oxide film that does not cause cracks or peeling, so it is possible to form a highly accurate mask pattern on a substrate. It is particularly advantageous.

[0024]

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

Example 1 OFPR-800 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied to a thickness of 2 μm on a silicon wafer having a step of 1.5 μm on which aluminum was vapor-deposited, and heated at 200° C. for 30 minutes. After forming the first layer of flattening film, TEFP (manufactured by Tonen Co., Ltd.), which is a 20% by weight xylene solution of a reaction product of halogenosilane and ammonia, was applied on top of it at 2000 rpm.
Spin coating was performed at 500°C in air, dried at 150°C for 30 minutes to form a polysilazane film, and then dried at 500°C in air for 60 minutes.
By firing for 0 minutes, a second layer consisting of a silicon oxide film is formed.
An interlayer film was formed. No cracks were observed on the surface of this silicon oxide film, and it was a highly homogeneous film. Furthermore, no peak indicating the presence of water was observed in the infrared absorption spectrum of this silicon oxide film.

Next, on the obtained silicon oxide film, TSMR-V50 (manufactured by Tokyo Ohka Kogyo Co., Ltd.), which is an i-line sensitive positive type photoresist, was applied with a spinner at 4000 rpm for 20 minutes.
After forming a resist film with a thickness of 1.0 μm as the third layer by applying it for 90 seconds on a hot plate at 90°C,
1iA (manufactured by Hitachi, Ltd.) and then immersed in a 2.35% by weight tetramethylammonium hydroxide aqueous solution for 1 minute to dissolve and remove the i-line irradiated portion. A resist pattern was formed on the two-layer intermediate film.

Next, a mixed gas of carbon tetrafluoride, trifluoromethane and helium was added at 25, 25 and 1
The oxide film etching device TUE-1101 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was used at a flow rate of 0.00 (SccM).
．． After etching and removing the silicon oxide film using the resist pattern as a mask under conditions of 7 Torr and 150 W, the first layer planarization film was removed by reactive ion etching using oxygen gas using the obtained silicon oxide film pattern as a mask. When a pattern was formed on a silicon wafer by removing it by etching, an extremely accurate pattern was formed even at the step portion.

Example 2 20 TEFPs similar to those in Example 1 were deposited on a silicon wafer having a step of 1.5 μm on which aluminum was vapor-deposited.
The process of spin coating at 00 rpm, drying at 150°C for 30 minutes, and baking at 500°C for 60 minutes in the air to obtain a silicon oxide film was performed twice to form a thick film with properties as a flattening film. A silicon oxide film was formed. No cracks were observed on the surface of this silicon oxide film, and it was a highly homogeneous film. Further, in the infrared absorption spectrum of this silicon oxide film, no peak indicating the presence of water was confirmed.

Next, a resist pattern is formed on the silicon oxide film by the same operation as in Example 1, and the silicon oxide film is etched away using the resist pattern as a mask by the same operation as in Example 1, thereby forming a silicon wafer. When a pattern was formed on top, extremely accurate patterns were formed even on the stepped portions.

Comparative Example Instead of the TEFP (manufactured by Tonen Co., Ltd.) used in Example 1, a coating liquid with a SiO2 equivalent concentration of 12% by weight obtained by partially hydrolyzing tetraethoxysilane in the presence of ethyl alcohol was used. A second intermediate film made of a silicon oxide film was formed in the same manner as in Example 1, except for the use of the following.

The occurrence of cracks on the surface of this silicon oxide film was confirmed, and an absorption peak in the range of 3200 to 3600 cm -1 caused by water was confirmed in the infrared absorption spectrum. Next, a resist pattern was formed on this by the same operation as in Example 1, and a peeling phenomenon was observed in the resist pattern.

Claims (2)

[Claims] 1. A laminated material for a three-layer resist method having a structure in which a first layer consisting of a flattening film, a second layer consisting of an intermediate film, and a third layer consisting of a resist film are laminated on a substrate to be processed. A laminated material for a multilayer resist method, characterized in that the intermediate film is made of a silicon oxide film formed under non-aqueous conditions. [Claim 2] A first film made of an intermediate film is placed on the substrate to be processed.
A multilayer resist method characterized in that the interlayer film is a silicon oxide film formed under non-aqueous conditions in a laminated material for a two-layer resist method having a structure in which a second layer consisting of a resist film and a second layer are laminated. For laminated materials.