JPS60208752A - Composition for peeling photoresist - Google Patents

Abstract

PURPOSE:To eliminate poor removal of minute patterns and to improve peelability of a photoresist by using a homooligomer or cooligomer of an unsatd. ester having a polyfluoroalkyl group specified in C number. CONSTITUTION:The oligomer used here is a homo- and/or co-oligomer of an unsatd. ester having 4-20C polyfluoroalkyl group, preferably, such as an oligomer of acrylate or methacrylate having terminal perfluoroalkyl group, and a peeling soln. contg. it in an amt. of 0.01-5.0wt% is used. The objective photoresist may be of any type. This peeling compsn. is suilable for peeling the photoresist, especially in the case of manufacture of semiconductors, and the use of it permits poor peeling of mimute patterns to be prevented, soluble parts to be peeled in a short time, and pinholes due to swelling and film thinning to be prevented on the insolubilized parts. It is widely used for other photoresist applying fields.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photoresist stripping composition in which the stripping properties of the photoresist are improved by incorporating a specific fluorine-based oligomer.

When forming fine integrated circuits on wafers such as silicon and manufacturing C and LSI, the steps are resist coating → prebake → exposure → development → rinse → boss bake → etching →
A resist process consisting of resist stripping steps is employed. During development, it is necessary to peel off the exposed portions for positive photoresists and the unexposed portions for negative photoresists. Furthermore, when removing the resist, it is necessary to remove the resist that has hardened during post-baking. LSI by increasing the density of engineering C.

As the degree of integration increases toward VLSI, the line width of circuit patterns is becoming finer down to submicrons.

Therefore, in the development step, a stripping agent that is excellent in stripping only the solubilized photoresist is required, and in the resist stripping step, a stripping agent that can completely strip the hardened resist It is required.

The inventors of the present invention have conducted intensive studies to develop a high-performance stripping composition for use in such development or stripping processes, and as a result, they have discovered an even more superior composition by incorporating a specific fluorine-based oligomer. was found to be obtained. That is, the present invention includes a homopolymerization oligomer of an unsaturated ester containing a polyfluoroalkyl group having 4 to 20 carbon atoms and/or a copolymerization oligomer of the unsaturated ester and another copolymerizable compound. The present invention relates to a characteristic photoresist stripping composition. The stripping composition of the present invention can strip the soluble portion of the photoresist in a short time without causing defects in removing fine patterns during the development process, and prevents swelling of the resist pattern, which is the insolubilized portion, and vibration of the resist. There are no problems such as pinholes or easy peeling of the resist. In addition, in the resist stripping process, the temperature is lower to remove fine details (9, hardened resist).
1. It has excellent characteristics such as being able to be completely peeled off.

The fluorine-based oligomer in the present invention has 4 to 20 carbon atoms.
A homopolymerized oligomer of an unsaturated ester containing polyfluoroalkyl groups (hereinafter referred to as oligomer A) and/or a copolymerized oligomer of the unsaturated ester and another copolymerizable compound (hereinafter referred to as oligomer B). .

Oligomer A includes not only polymerized oligomers in which the number of carbon atoms in the polyfluoroalkyl groups in the heptadmers is the same, but also polymerized oligomers in which the number of carbon atoms is different.

The unsaturated ester containing a polyfluoroalkyl group having 4 to 20 carbon atoms is not particularly limited, but for example, the following acrylates or methacrylates are preferred.

0PB(OF2)40H20000(OH3)=(3H
.

OFa (C1”z)s (O horse) 20000 (OH3
) = OH.

0F3(01%)g 0OOOH=OHz(!Fa(O
F,)70H,0H20000H=OH.

OF, (OF2) 780. N(OsH7)(OH鵞)t
0OOOH==OH.

C horse (OF,)7 (OH2), 0OOOH=OH.

0F3(OF,)780tN(OEm)(OR,,),
0000(OH3)=OH.

'Pa (O1'z)y BOOH(03HIri(OH
I) 20000H=OH2CFM (oFri70ON
H(OH3)1 oaooa=: oH.

CFs (OF2)a (O horse) 20000H=OHz
011'3((3F meaning)s (OH,), 0000(
GIH,) = OH.

011FI (CIFI) @ 0ONH (OH2) 100
00(OHB) = 0H2H(CI!',)loO
H,000(!H= 0H20F201(OFs+)t
o OH,0000(OH3) = OH2 The compound that can be copolymerized with the unsaturated ester can be selected from a wide range as long as it does not impede the effects of the present invention. For example, ethylene-vinyl acetate, vinyl chloride, vinyl fluoride,
Vinylidene halide, styrene, α-methylstyrelkyl ester, methacrylic acid and its alkyl ester,
Poly(oxyalkylene) acrylate, poly(oxyalkylene) methacrylate-traacrylamide, methacrylamide, diacetone acrylamide, methylolated diacetone acrylamide, N-methylol acrylachate, vinyl alkyl ether, halogenated alkyl vinyl ether, vinyl alkyl ketone.

Butadiene 1 inglene, chloroprene, glycidyl acrylate, benzyl methacrylate.

benzyl acrylate, cyclohexyl acrylate,
It is possible to copolymerize one or more types of polymerizable compounds that do not contain perfluoroalkyl groups, such as maleic anhydride, aziridinyl acrylate or hamethacrylate, and N-vinylcarbazole, as constituent units of the copolymerized oligomer. It is. The copolymerization ratio of these copolymerization components to the unsaturated ester containing a polyfluoroalkyl group is usually 1 to 70% by weight, particularly preferably 10 to 50% by weight. In order to obtain a raw material, a polymerizable compound is dissolved in a suitable organic solvent, and solution polymerization is carried out by the action of a polymerization initiation source (a peroxide, an azo compound, or ionizing radiation a that dissolves in the organic solvent used). A sagging method can usually be adopted. Suitable solvents for solution polymerization are toluene, ethyl acetate, inglovil alcohol, 1,1,2-)dichloro-1,2,2-trifluoroethane, tetrachlorodifluoroethane, methylchloroform, and the like. Such oligomers may have number average molecular weights in the range of approximately 1,000 to 50,000.

The structure of oligomer B is a random type in which an unsaturated ester containing a polyfluoroalkyl group and another copolymerizable compound are randomly arranged, a graft type in which unsaturated esters containing a polyfluoroalkyl group are grouped together, etc. A structure such as a graft type in which copolymerizable compounds are grouped together, or a block type in which an unsaturated ester portion containing a polyfluoroalkyl group and another copolymerizable compound portion are separated may be adopted.

Solvents constituting the stripping composition of the present invention include alkali phosphates, alkali silicates, alkali borates, alkali carbonates,
Alkali water injection solutions such as alkali acetate and alkali benzoate, hydrocarbons such as toluene, cyclohexane, and hepta, tetrachloroethylene + 1.1.2-trichloro-
Trifluoroethane, 1,1.1-tri'loloethane,
Halogenated hydrocarbons such as methylene chloride 1. acetone,
Ketones such as methyl ethyl ketone and methyl imbutyl ketone, alcohols such as ethanol, ingropanol, n-7" lobanol, benzyl alcohol, aromatic sulfo/acids such as dodecylbenzenesulfonic acid, phenols such as cresol and phenol, Examples include esters such as ethyl acetate and inamyl acetate, ethers such as ethylene glycol monomethyl ether and tetrahydro-7rane, and amides such as dimethylformamide.

In the resist stripping process, hot concentrated sulfuric acid, fuming nitric acid, hydrogen peroxide, etc. may be used. The blend iIt of oligomer A and/or B in these stripping solvents is 0.01 to 5.0
% by weight, preferably 0.1-1. It is sufficient to use a small amount of Oi lid, and when oligomer A and Bf are used in combination, it is preferable to use oligomer BQ as the main component.

Examples of the photoresist include, but are not limited to, positive or negative light exposure resists, deep ultraviolet exposure resists, and X-ray or electron beam resists. The material of the resist for light exposure is quinonediazide based on phenol and cresol novolak resin, cis-1,
There are cyclized rubber based on 4-polyene, polycinnamic acid, etc. For deep ultraviolet resists, there are polymethyl methacrylate, polymethyl impropenyl ketone, etc., and for electron beam and X-ray resists. Although polymethyl methacrylate 9, glycidyl methacrylate-ethyl acrylate copolymer, methyl methacrylate-methacrylic acid copolymer, and the like are known, the uninvented stripping composition is effective for all of them.

The stripping composition of the present invention is particularly suitable for stripping photoresists during semiconductor manufacturing, but can also be used in other photoresist application fields, such as printed wiring boards, lead frames, electronic component fields such as TV shadow masks, and metals. ,ceramic.

It is also extremely effective as a remover in the field of etching glass, etc.

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

"Synthesis of fluorine-containing oligomer" 1. The following composition was reacted in an autoclave at 70°C for 15 hours to synthesize fluorine-containing oligomer (I)'.

(Molecular weight approximately 4,000) a9Flt a-OR,0OOC! III=OH,2
0 parts by weight 1.1.2-) Lichloro-1,2,2) Lifluoroethane 502-2' Azobisin butyronitrile 0.5n -OB HI38 H1,8 2, in an autoclave at 80°C for 15 hours below A fluorine-containing oligomer (...) was synthesized by reacting with the following composition.

(Molecular weight approximately 4,000) 08F,,802N(0,H5)-0H20H2000
0H=OH, 10 parts by weight Toluene 50 2-2' Azobisin butyronitrile 0.5n-08
H17SH1,83 was reacted with the following composition in an autoclave at 80°C for 15 hours to synthesize a fluorine-containing oligomer [)'(c).

(Molecular weight approximately 5,000) 091180ONH0.1m0000H=Ohorse 20 parts by weight OH,=O-0H310 00008H17' Ethyl acetate 50 2-2'-Azoinbutyronitrile 0.8n -Og
HI3 SH1,4 Example 1 A photoresist agent made of methyl methacrylate-methacrylic acid copolymer was applied onto a silicon wafer and dried to form a resist film.

After baking at 100°C for 30 minutes, irradiating with electron beam,
Lines and spaces with an average size of 20μ were formed. Next, 1.0% by weight of fluorine-containing oligomer 'e-containing tr20
It was immersed in 1.1.1-trichloroethane at 1.1.1° C., and the resist solubilized portion was peeled off. The peeling time was measured by checking the peeling condition with a microscope. The results are shown in Table 1.

In addition, in the case where the fluorine-containing oligomer was not added, poor extraction of fine patterns was observed.

Table 1 Example 2 A photoresist agent made of polyurethane was applied onto a silicon wafer and dried to form a resist film. Then, 100℃-30 minutes of Gribake, exposure and 160℃-4
The resist film was solidified by performing a 0 minute post bake.

The resulting resist film was coated with 9 parts by weight of 70 parts by weight of perchlorethylene, 20 parts by weight of phenol, 10 parts by weight of dodecylbenzenesulfonic acid, and 1 part by weight of fluorine-containing oligomers.
The film was immersed in a release agent at 0°C and 120°C, and the time until the film was completely removed was measured. The results are shown in Table 2.

Table 2

Claims (1)

[Claims] 1. Contains a homopolymerization oligomer of an unsaturated ester containing a polyfluoroalkyl group having 4 to 20 carbon atoms and/or a copolymerization oligomer of the unsaturated ester and another copolymerizable compound. A photoresist stripping composition characterized by: 2. The photoresist stripping composition according to claim 1, wherein the unsaturated ester containing a polyfluoroalkyl group is an acrylate or methacrylate containing a terminal perfluoroalkyl group.