JPS5861106A - Method for forming fluoroalkyl acrylate polymer film on substrate - Google Patents

Abstract

PURPOSE:To obtain a coating film of the titled polymer useful as a coating film of resist having high sensitivity, by polymerizing a specific fluoroalkyl acrylate, etc. in the presence of tetramethyltin using inert gas excited by glow discharge. CONSTITUTION:(A) A fluoroalkyl acrylate of formula (Rf is 1-15C perfluoroalkyl group or a group having one or more fluorine atoms and obtained by substituting one or more fluorine atoms of the above perfluoroalkyl group with H atoms; R<1> is H, methyl, ethyl, or halogen; R<2> is bivalent hydrocarbon group), (B) a polymerizable substance other than the component (A) as an optional component, and (C) tetramethyltin, are fed from the container 8 to the vacuum chamber 1 filled with argon supplied from the argon container 2. The monomers, etc. are polymerized with an inert gas excited by passing through the glow discharge zone generated by the dielectric coil 4 connected to the radio frequency wave generator 7 through the watt meter 6 and the impedance matching circuit 5 to form a polymerized coating film on the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of forming a polymeric coating, and more particularly to a method of forming a resist coating.

The present inventors have previously shown that fluoro-tetraalkyl acrylates can be formed into a single film on a substrate by a single discharge, and that this film is patterned with high-energy radiation and further developed. He discovered that a fine resist pattern could be formed by this method and filed a patent application (Japanese Patent Application No. 142198-1982).

That is, (1) (by the inert gas excited by the one-shot discharge, (b) formula: RfR20000R1=rm2 (wherein, Rf is a straight or branched perfluoroalkyl having 1 to 15 fl carbon atoms) or a group in which one or more lenofluorine atoms are substituted with a hydrogen atom and has at least 7 fluorine atoms, R1 is a hydrogen atom, a methyl group, an ethyl group, or a hydrogen atom, and one is a divalent hydrocarbon residue. A homopolymer or copolymer of fluoroalkyl acrylate on a substrate characterized by polymerizing (0) a polymerizable substance other than (b) as necessary. A method of forming a polymer coating of a mixture of a homopolymer of a fluoroalkyl acrylate and a homopolymer of another polymerizable material, and (g) (A) (4) by means of an inert gas excited by a glow discharge. , (b) Formula: RfR2oaocm: = OH, IB
(In the formula, ~ is a linear or branched barfluoroalkyl group having 1 to 15 carbon atoms, or a group in which one or more fluorine atoms are replaced with a hydrogen atom and has at least one 7 atom, R1 is a hydrogen atom, a methyl group, an ethyl group, or a hydrogen atom, and R2 is a divalent hydrocarbon residue); and (0) optionally a polymerizable substance other than (kl). (B) irradiating the film with high-energy rays to draw a latent image pattern; (0) Finally, developing the resist pattern. This is a method of manufacturing a substrate having a coating.

In this method, Q. 50 in 5pm resist film
Although a pattern can be formed with a local irradiation dose of ~250°C and good sensitivity can be obtained, it is still insufficient.

An object of the present invention is to obtain a resist film made of a fluoroalkyl acrylate-F polymer produced by G-discharge polymerization with even better sensitivity. With active gas, (Sequence: RtR20000R1=Cni2 (in the formula, Rf is a linear or branched barfluoroalkyl group having 1 to 15 carbon atoms, or one or more fluorine atoms thereof is substituted with a hydrogen atom, and at least fluorine atom 1
1 represents a hydrogen atom, a methyl group, an ethyl group, or a heligen atom, and 1 represents a divalent hydrocarbon residue.

) and (b) optionally polymerizable substances other than (&) are polymerized together with (0) tetramethyltin to form a film of a fluoroalkyl acrylate polymer on a substrate. The present invention also relates to a method for producing a substrate having a resist pattern coating, which comprises irradiating the coating with high-energy rays to draw a latent image pattern, and finally developing the coating if necessary.

According to the present invention, a pattern can be formed on a resist film having a film thickness of 0.2P with an irradiation dose of about 24".

The excited inert gas in the present invention has a temperature of 0 to 20
0°01 pressure 10~10 TorrJ or 1~1
Passing inert gas through the gas discharge area at 0.2 Torr20
00m38TP/min, and the green discharge is 0.
．． 1~1QQ under white high frequency electric field 1~500W, especially 5
Preferably, it is carried out with a radiating power of ~50 W. The green discharge is carried out either by providing two parallel plate electrodes inside the reaction tube and applying a high frequency voltage, or by providing an induction coil outside the reaction tube and applying a high frequency current.

The inert gas can be helium, neon, argon, krypton, xenon, preferably argon and krypton.

The fluoroalkyl acrylate used in the present invention is represented by the above formula. The 〇- group has 1 to 151!1 carbon atoms, preferably 1 to 10 carbon atoms, and has at least 1 fluorine atom, preferably is at least 1/2 of the sum of the number of carbon atoms in the Rf group and the number of carbon atoms in the f group. The R2 group is an acrylate group or a methacrylate group and R
The number of carbon atoms is preferably 1 to 10, particularly 1 to 5, but is not critical. Preferred fluoroalkyl acrylates have a boiling point of 400° or less or 40τerr at atmospheric pressure.
It must be 70 phrases or less.

Examples of fluoroalkyl acrylates used in the present invention include 0H2=0(OH3)OOOOOH,2(Cff2),
$Q)12 = 0(OH3)0000(aH3)2(
OF, 2) 2HOH, 2= O(J!H3)OOOaH
2H17730H2= 0(aH3)OOOOOH@72
0HFOF30H2= O(OH3)OOOOOH(OH
3) OIF, IQHPGF3aH2== O(OH3)
OOOOH(02)13)m! 2011ICPI30H
g W 0(OH3)0000H(03117)075
Gi7OF30HJ! x 0(OH3)0000(O
H3), dν2Gi'PO? 3(M2 = 0(OH3
)0000(OH3)(O枦5)OF10H]]IO'
F30H2= 0(OH3)0000((!H3)10
1F20H((7F3)2σH2=O(OH3)OOO
Examples of OH1tM2(01g)n7n include 1 to 10.

In the present invention, such fluoroalkyl acrylate is used in a proportion of 0.5 to 50% of the inert gas flow rate.
Preferably, it is supplied at a rate of ~20%.

In the present invention, the polymerizable substances other than Xun, which are used as necessary, are vinyl monomers having double bonds.

Examples of the vinyl monomer include ethylenically unsaturated olefins such as ethylene, propylene, butylene, isobutylene, and butadiene; styrenes such as styrene, a-methylstyrene, and p-crylstyrene; acrylic acid, methacrylic acid, Unsaturated carboxylic acids such as itaconic acid, maleic acid, maleic anhydride 117 Methyl acrylate, ethyl acrylate, isobutyl acrylate, isobutyl acrylate, dodecyl acrylate, isobutyl acrylate, 2-chloro-ethyl acrylate, acrylic l ! 7
a, methyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, a
- Esters of a-methylene aliphatic monocarboxylic acids such as ethyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl chloride, vinyl acetate, vinyl pionate, etc. , vinyl esters such as vinyl butyrate and vinyl benzoate + 1-methyl-1'-methoxyethylene, 1
．． 1'-dimethoxyethylene, 1,2-dimethoxyethylene, 1,1'-dimethoxycarbonylethylene, 1-
Ethylene derivatives such as methyl-1'-ditriethylene
N-vinylbilyl, N-vinylcarbazole, vinyl indole, N-vinylvinylvinyl, N-vinylpyridonato-vinyl compounds; other acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, a-ethyl Examples include acrylamide, acrylanilide, di-acryloacrylanilide, m-ditriacrylanilide, m-methoxyacrylanilide, vinylidene acrylide, and vinylidene cyanide.

The proportion of such vinyl monomer is preferably 60 moles or less of the total amount with fluoroalkyl acrylate.

A known method can be adopted for making fluoroalkyl acrylate.

For example, fluoroalcohols can be reacted with acrylic acid or methacrylic acid or derivatives thereof.

QH2=OR”0OOH+RfR”Oto-1→CH
2=OR'oooop2R and -4-R20 (wherein R1
, R2 and k are the same as above. ) Specifically, for example, 2,2,5,4,4,4-hequinafluoributyl alcohol is added to methacrylic acid acid, and a small amount of a polymerization inhibitor, such as Heid ν quinone dimethyl ether, is added. - Heated to 120°a, 2t2.5t4.4
．． 4-Hequinafluorobutyl methacrylate can be produced.

The ratio of tetotsumethyltin to fluoroalkyl acrylate is 0.1 to 20 times, and <0.5 to 1%.
A zero attack is preferred.

The substrates used in the present invention are not limited, and include, for example, salt crystals, Yuta mastered glass plates, semiconductor films such as silicon and germanium, conductive films such as chromium, arsenium, titanium, and gold, silicon oxide, and silicon nitride. Examples include insulator films such as phosphorus silicide glass, arsenic silicide glass, and boron silicide glass. Such a substrate is placed within the discharge zone or downstream of the discharge zone.

To carry out the invention, for example, the apparatus shown in FIG. 1 is used. While adjusting the pressure to a predetermined level using a vacuum pump, supply inert gas, fluoroalkyl acrylate, and tetramethyl anchor, place the substrate on a horizontal or vertical document mounting table, and apply a high-frequency voltage to generate a glow discharge. When this is done, a coating of fluoroalkyl acrylate polymer is formed on the substrate.

The polymer coating/film thus formed is pre-baked together with the substrate at a temperature of 70 to 200°C as necessary.

The substrate coated with the polymer may be subjected to high-energy radiation such as electron beams, X-rays, etc. without prebaking or after prebaking.
A pattern is drawn on the film by irradiating it with ms ultraviolet rays, etc.
By developing this as necessary, a film having a fine resist pattern can be formed on the substrate.

For development, if drawing is done by electron beam irradiation, electron beam irradiation alone may be sufficient in some cases when the thickness of the resist film is small. In the case of development, electron beam irradiation can be kept small, which is preferable.

Furthermore, this development is carried out using an electron beam, x
This can also be done by eluting the Is irradiated portion.

In oxygen plasma etching, the gas pressure is 1 to 600 mT.
orr % temperature of 0 to 100°0, a polymer coating with a latent image on the substrate is placed together with the substrate, for example on one pole of a parallel plate circular electrode, with insulation if necessary, and oxygen is passed through. Do it while doing it.

Oxygen is best mixed with an inert gas such as red,
In addition, the 02 concentration in the Ar-02 mixed gas is 10 to 200
~20 mm for a container volume of 10 to 100 usually 61
Pass the mixed gas through am'BTP and Ais. The discharge power is preferably 0.2 to 2 W per 1 o of interelectrode volume.

Development by heating is from 1 to 1 O-5), preferably 10
It is preferable to carry out the reaction under reduced pressure of ~10 Torr and at a temperature above the glass transition point of the polymer that does not cause thermal decomposition, generally from 80 to 250'O.

Hydrogen or inert gas plasma etching
By placing the polymer coating formed on the substrate in a hydrogen or inert gas plasma maintained at a temperature of 5°C to 100°O at a gas pressure of 10 Torr, preferably 10-2 to 10" Torr. For example, argon, helium, nitrogen, etc. can be used as the inert gas.Specifically, the polymer coating is placed on one plate of the parallel electrodes so that it faces the other plate. Place the substrate on which the film has been formed.If necessary, the substrate and the electrode plate may be insulated.The flow rate of hydrogen or inert gas is usually 0.
1 to 10 (1m"57P/fa1m, and discharge may be performed with a discharge power of 0.05 to 1W per interelectrode volume 1(2)3.The discharge time may be adjusted as appropriate depending on the conditions above. do it.

The resist pattern film thus formed can be applied to the production of conductor elements, magnetic bubble elements, optical application parts, and video disks.

The method of the present invention will be explained in more detail with reference to Reference Examples and Examples, but the present invention is not limited to these Examples.

Reference Example 1 A film of a fluoroalkyl acrylate polymer was formed on a substrate using a plasma polymerization apparatus shown in FIG.

The vacuum container (1), which is the main body of the device, has a total volume of 11, and the pressure inside the vacuum container (1) is the same as that of the vacuum pump 01)! The pressure was adjusted to 0.7 Torr with a four-door vacuum needle (8), and the gas in the vacuum vessel was evacuated via a liquid nitrogen trap (8). 63. Argon is supplied from the argon container (2) at the tip.
Supplied with 5am 87P/1ain, radio wave generator (
7) From the power needle (6) and the impedance adjustment circuit (
15.56MH generated in the dielectric film (4) via 5)
Argon was excited by passing through the glue discharge area of a.

On the other hand, from the container (8), a mixture of fluoroalkyl acrylate and tetramethyltin was added at 1.6 (11!l'8).
/wa i m was supplied into the vacuum volume #(1) at a flow rate of argon, and the substrate (not shown) placed on the sample mounting table (9) was cooled with cooling water after merging with the excited argon. ) and evacuated with a vacuum pump αυ.

The conditions for forming the film were as follows.

Temperature around the glass plate device on which the substrate was vapor-deposited Gas pressure in the heated vacuum chamber: 0,7 torr Glow release: 11
Power 10W Argon flow rate 66
．． 5am3BTP/11n fluoroalkyl acrylate WdlL 1.5soJ8τL/-4n tetofmethyltin inflow 0. Q5om3ffi5ai
臘Contact time and go separation thickness were measured using Talystep. The film thickness was 1.6 μm.

Example 1 Electron beam lithography was performed on a film formed on a p-smooth layer on a glass plate under the same conditions as in Reference Example 1, and the amount of decrease in film thickness with respect to various irradiation doses was measured. Electron beam drawing is 10
-'~10-') - Electron beam is 1~2μ010- with acceleration voltage 20kV and line and space 4μ weight.
The amount of decrease in film thickness was measured using Talystep. The results were as follows.

Irradiation dose Reduction in film thickness (μO/am”) (μm) 1
0.04 1.5 0.12 2 0.25 Example 2 A film coated on the adhesive layer on a glass plate under the same conditions as Reference Example 1 was irradiated with electron beams at various irradiation doses as in Example 1. I did this. Then, heat treatment was performed at 170 oO for 4 minutes under reduced pressure of 10 -3 to 10 Torr. The results are shown below.

Irradiation dose Total film thickness reduction (μO/am”) (μm) 1
0.0a 1.5 0.23 2 0.48 Example 3 A film formed on a four-layered layer on a glass plate under the same conditions as Reference Example 1 was exposed to electrons at various irradiation doses in the same manner as Comparative Example 1. Ray irradiation was performed.

These coatings were then treated with hydrogen plasma. Hydrogen plasma treatment was carried out by placing the sample on the lower electrode plate of a parallel disc electrode (100 mm in diameter, 50 mm apart) with the film facing upward, and applying hydrogen at a frequency of 12$-56M while flowing hydrogen.
A high frequency voltage of Hz was applied.

The conditions for the hydrogen plasma treatment were as follows.

Discharge power 100W Hydrogen pressure 2 mTorr Hydrogen flow rate 1~100 mm' 8 TP/ia
In discharge time: 1 minute The results are shown below.

Irradiation dose Total film thickness reduction (μO/am”) (μ!1I)1
0.06 1.5 0.212
0.45 Reference Example 2 A polymer film of fluoroalkyl acrylate was formed on a substrate in the same manner as in Reference Example 1.

The conditions for forming the film were as follows.

Substrate Glass plate with chromium vapor deposition Temperature around the device: Room temperature Gas pressure inside the vacuum chamber: 0.7 Torr Glow release 11
IL power 10W argon flow IIb &, 5a
rn3STP/m1xr fluoroacrylate-2,5a
m38TP/11m tetramethyltin flow 1 0
．． 1om3BTP/aim contact time: 60 minutes Film thickness was measured using Talystep. The film thickness was 1.9 μm.

Example 4 For reference and under the same conditions as in Example 2, electron beam lithography was performed on a film formed on the p-smooth layer on a glass plate, and the amount of decrease in film thickness with respect to various irradiation doses was measured. Electron beam drawing is 1
0 ~ 10"-')-Line and space below 4
The film was irradiated with an amount of 11111 to 2μ010 μm, and the reduction in film thickness was measured using a tari step. The results were as expected.

Irradiation S amount Amount of film thickness reduction (1o/.,,) (voice+!1) 1 0.04 L, S O, 10 20, 22

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of a plasma polymerization apparatus for carrying out the method of the present invention. (Drawing codes) (1): Vacuum vessel (2): Argon vessel (8): McLeod vacuum gauge (4): III electric coil (6)! Impedance mu circuit (6)! Electric power meter (7) g Radio wave generator (a) Container for mixture of rich y olefin alkali ate and copper tetramethyde (9) 8 sample installation stand a 1; liquid nitrogen silica 0 υ: vacuum pump

Claims (1)

[Claims] 1. By the inert gas excited by the green discharge, (→Formula I RfR20GOGR1=0RB (wherein,
Rf is a linear or drum-like perfluorinated group having 1 to 15 carbon atoms or a fluorine atom of 111
The above groups are substituted with hydrogen atoms and have at least 111 fluorine atoms, R1 is a hydrogen atom, a methyl group, an ethyl group, or a halogen atom, and R2 is a bulky divalent hydrocarbon residue. ) and (b) optionally a polymerizable substance other than (0) tetramethyltin on a substrate, a coating of a polymer of fluoroalkyl acrylate-F. 2. (SJ formula: RfR”0OOOR1=s CIH2
(In the formula, 7 is a linear or branched perfluorinated alkyl group having 1 to 15 carbon atoms or a group in which one or more fluorine atoms are substituted with a hydrogen atom and has at least one fluorine atom; R1 is Hydrogen atom, methyl group, ethyl group or halogen atom and R2 represent divalent softened hydrogen residues) and (b) if necessary (polymerizable substances other than ) Polymerize with tetramethyltin to form a polymer film on the substrate, (then irradiate the film with high-energy rays to draw a latent image pattern, and (0) finally develop as necessary. 6. The method according to claim 2, wherein the developing method is heating or plasma etching.