JPS6010249A - Formation of pattern - Google Patents

Abstract

PURPOSE:To enable optional selection of a developing mode by using a polymer producing free radicals on irradiation of electron beams and a monomer having a functional group capable of graft cross-linking with said radicals under the irradiation of electron beams and forming another soluble polymer. CONSTITUTION:A resist material contains (A) a polymer or a copolymer capable of producing radicals on irradiation of electron beams, such as p-vinylbenzoyl-p- tert-butylperbenzoate or a copolymer of itself and styrene or its deriv., (B) a monomer having a functional group capable of graft cross-linking with said radicals under the irradiation of electron beams to form another solubilized polymer, such as acrylic acid, allyl alcohol, or allylamine. After the irradiation of electron beams, the unreaced monomer is removed by baking it, and then, the resultant solubilized polymer is developed by optionally selecting a developing soln. in accordance with its solubility.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for forming /arm turns, and more particularly to a method for forming a turn after any type of wet development by irradiating a resist material with high energy radiation such as an electron beam. The present invention relates to a method of forming a positive resist pattern. This method of forming an arm turn can be particularly advantageously used in a microfabrication process for manufacturing a hand conductor device.

BACKGROUND OF THE TECHNOLOGY In the field of manufacturing conductor devices, it is well known that high-energy radiation, particularly electron beams, is used to carry out microfabrication on the order of saramicrons. For such microfabrication, various types of positive resist materials for electron beam exposure have been proposed and are commercially available. Such positive resist materials for electron beam exposure usually consist of a resolving disc 4 reamer such as polymethyl methacrylate. That is, when such a polymer is exposed to light, its main chain is first cut by electron beam irradiation, and the molecular weight of the electron beam irradiated portion is reduced. A decrease in molecular weight means that the solubility of that part in the developer (used in the next step) has become greater than that of the non-irradiated area, and therefore,
During subsequent development, only the solubilized region is selectively dissolved and removed to obtain a positive resist with 9 turns.

Prior Art and Problems As is clear from the above, when implementing the master turn forming method using a positive resist material for electron beam exposure, a solubility difference is introduced into the resist material as a result of electron beam irradiation. This is an essential requirement, and materials that meet this requirement are extremely limited. The drawback of such limited resist materials is that they have poor heat resistance and plasma resistance. Such drawbacks cause deformation or decomposition of the resist polynes during the plasma etching process, and cannot guarantee a satisfactory function as a resist.

In addition, when implementing the conventional arm turn forming method, it is virtually impossible to arbitrarily select the development form, and as a result of taking various factors into consideration, in many cases a specific I have no choice but to rely on developer. Such limitations on the development form also mean limitations on the resist material.

Object of the Invention The present invention provides that, when forming a positive resist polymer, it is possible to select a resist polymer from a wide range of polymers (l) and a wet development method can be used as the development method, such as organic development or alkaline development. It is an object of the present invention to provide a pattern forming method that can use both development and acid development.

According to the present invention, the above-mentioned object is to provide a polymer or copolymer capable of generating diradicals by electron beam irradiation, and a polymer or copolymer that is graft-bonded to the radicals under electron beam irradiation and to a developer. Using a resist material containing a monomer that contains a functional group that solubilizes the copolymer, and which can remove unreacted functional groups by heating under a predetermined reduced pressure, a positive resist material is used to form a positive resist material by electron beam irradiation, and a 9-turn distoning process is performed. This can be achieved by forming

In practicing the present invention, any polymer or copolymer may be used as long as it is capable of generating radicals in the side chain moieties upon electron beam irradiation, i.e., radicals to which the monomers described below can be grafted. can. In fact, the present invention does not rely on the generation of solubility differences due to cleavage of the polymer main chain, but instead relies on the solubilization of the electron beam irradiation region by the graft bond between the radical and the monomer.
Any desired durable resist polymer can be used. From research conducted by the present inventors, it has been found that poly(p-vinylbenzoyl-
It has been found that it is possible to use particularly advantageously p-tart, -guyrno-penzoate) or copolymers thereof with styrene or styrene-cast conductors.

When carrying out the present invention, only the electron beam irradiation area is
i#! In order to solubilize the monomer in the liquid, use a monomer having a functional group that can be graft-crosslinked to radicals from the radical-forming polymer or copolymer under electron beam irradiation to form another solubilized polymer. is necessary. The monomer used here needs to have a certain high vapor pressure. Unreacted monomers with high vapor pressure will be removed under vacuum or reduced pressure during subsequent baking without adversely affecting resolution or sensitivity. When selecting the seven-layer composition of the present invention, it is possible to do so by considering the type of development to be used. That is, the functional group of the monomer can be arbitrarily selected so that the solubilized polymer produced by the combination of the functional group and the radical can be made soluble in any developer.

As long as it satisfies the above-mentioned conditions, there are no particular limitations on the seven-pointer of the present invention. Monomers useful in the practice of this invention include, for example, acrylic acid, allyl alcohol, allyl amine, vinyl amine, hydroxystyrene, cal? Examples include xystyrene and aminostyrene.

The above-mentioned radicals and monomers may be bonded as necessary.
Alternative methods may be adopted. That is, while the generated radicals are alive, the radical-containing polymer can be exposed to the vapor of an appropriately selected monomer to bind the monomer to the moieties to obtain a solubilized polymer for any developer.

In the present invention, the generation of radicals from the radical-forming polymer or copolymer and the graft polymerization of the radicals with monomers are considered to proceed according to the following reaction mechanism. It is thought that polymerization (1) and (U) proceed in combination.

When carrying out the present invention, a wet development method commonly used in this technical field may be optionally used to remove the solubilized polymer or copolymer in the electron beam irradiated area, thus forming a positive tone and distoning nine turns. I can do it. Here, useful organic developers include acetone, xylene, benzene, toluene, etc., useful alkaline developers include a quaternized alkyl ammonium salt aqueous solution (for example, MF 312 manufactured by Shipley), and useful acid developers. Examples include acetic acid and the like.

The pattern forming method of the present invention can be carried out, for example, by the following procedure.

A resist solution is obtained by dissolving the selected radical-generating polymer or copolymer and a functional group-containing monomer in a suitable solvent such as benzene, xylene, or cellosolve solvent such as methyl cellosolve (MOL!). , 8i0□, PSG, etc. by a spin code method, a spray method, etc. The preferred thickness of the resist film is about 5,000λ to 15.0mm.
It is ol. The resulting resist film is baked in N2 at about 80-120°C for about 30-80 minutes.

After baking, the image/mother turn is exposed using an electron beam exposure device commonly used in this technical field. In the exposed area, as a result of electron beam irradiation, radicals are generated from the polymer or copolymer and the radicals are grafted to the monomer, thereby producing a solubilized polymer or copolymer.

After electron beam exposure, in order to remove unreacted monomers, especially those in unexposed areas, it is heated at about 80 to 120°C for about 0.5 to 1 hour under vacuum or under reduced pressure of about 10-2 to 10-5. Bake with. After the baking is completed, the resist film is developed with an organic developer, an alkaline developer, or an acid developer depending on the solubility of the solubilized polymer or copolymer to completely dissolve and remove the exposed portion of the resist film. In this way, a clear positive resist pattern corresponding to the exposed image pattern can be obtained.

Examples of the invention The invention will now be illustrated by the following examples.

Example 1: Poly(p-vinylbenzoyl-p-tert,-butyl perbenzoate) (molecular weight = 45000-5000
About 10% by weight of hydroxystyrene was added to 0) and dissolved in methylcellosolve acetate (MCA) to obtain a benzene solution. This benzene solution was spin-coded onto a silicon wafer to a thickness of about 1 μm, and heated at about 85°C for 33
Bake for a minute. After baking, exposure was performed using an electron beam exposure device at an acceleration voltage of 20 keV. After patterning, vacuum bake at approximately 120°C for 1 hour (
A 70% aqueous solution of MF 312 (manufactured by Shipley) was used for alkaline development. The electron beam irradiated area of the resist film was completely dissolved and removed, and a positive pattern (D0=7 to 12×10 Si1) was obtained. This resist pattern had excellent heat resistance and plasma resistance, and the subsequent processing of the substrate could be easily performed.

Example 2 In two cases, the procedure described in Example 1 above was repeated. However, using poly(p-vinylbenzoyl-p-tert-butylperbenzoe-)-CO-styrene) (9:1) (molecular weight = about 75,000 to 80,000, dispersity = 1.5), 5 wt % of p-carboxystyrene was added to form a film. Methyl cellosolve (
MC) was used. Almost the same results as in Example 1 were obtained.

Effects of the Invention According to the present invention, first, organic development, alkaline development, acid development, etc. can be used as desired depending on the type of polymer used, and therefore the resist polymer can be easily selected. is. Furthermore, it is possible to obtain a resist polymer with heat resistance and plasma resistance due to the ease of selecting the resist polymer, and perhaps the fact that the side chain moieties of the polymer are entirely conjugated systems. Although this is thought to be due to the above, it is possible to obtain plasma resistance superior to that of polynutylene-based resists, which are currently widely used.

patent applicant Fujitsu Limited patent application agent Patent Attorney Akira Aoki Patent attorney Kazuyuki Utate Patent attorney Yukio Uchida Patent attorney Akira Yamaguchi

Claims (1)

[Scope of Claims] 1. A polymer or colimer capable of generating diradicals by electron beam irradiation, which forms a G27F bond with the radicals under electron beam irradiation and solubilizes the polymer or copolymer in a developer. Contains functional groups such as
A pattern forming method characterized in that a resist material containing a monomer which is unreacted and can be removed by heating under a predetermined reduced pressure is positively molded by electron beam irradiation to form a resist pattern of nine turns. 2. The radical-generating polymer or copolymer is poly(p-vinylbenzoyl-p-tert,-butyl/
4'-benzoate) or a copolymer of it and styrene or a styrene derivative.