JPS61223733A - Resist coat - Google Patents

Abstract

PURPOSE:To obtain the titled coat facilitating a dry etching by forming a (co)polymer layer of a fluoroalkyl acrylate on a substrate and by laminating a metal layer of a fluoroalkyl acrylate on a substrate and by laminating a metal (compd.) belonging to the groups Ib, IIb and III-VII in the periodic table and having more than specific value of an atomic weight on the (co)polymer layer. CONSTITUTION:More than one kind of the polymer contg. the compd. shown by the formula wherein Rf is 1-15 C straight chain or branched chain perfluoroalkyl or alkyl group having more than one of a fluorine atom, R<1> is H, CH3, C2H5, or a halogen atom, R<2> is a two valent hydrocarbon group or a copolymer contg. the compd. mentioned above, and an another monomer, are provided on the substrate made of silicone. The thin film composed of the metal or the metal compd. belonging to the groups Ib, IIb and III-VII in the periodic table and having >=25 atomic weight is formed on the polymer or the copolymer. The oxygen gas plasma etching is performed by irradiating a high energy electron ray to the film from the thin layer side. The resist coat in which the irradiated part of the copolymer is removed together with the metal (compd.) layer coated on the copolymer, and the unirradiated part of the high energy ray is not etched with the oxygen plasma, is obtd, thereby obtaining the excellent semiconductor element.

Description

[Detailed description of the invention] [Industrial application field 1 The present invention relates to resist coatings.

[Prior Art] Chrome plating layer, a layer formed by applying a solution of a fluoroalkyl acrylate polymer onto a substrate such as silicon, or a fluoroalkyl acrylate layer formed on such a substrate by plasma polymerization. Plasma polymer layers are useful in fields such as the semiconductor industry as resist coatings.

When such a resist film is used, for example, after irradiation with high-energy radiation such as an electron beam, one formed from a solution is developed with a developer, one formed by plasma polymerization is subjected to oxygen plasma etching, or A resist pattern can be formed by irradiation with only electron beams or by other methods (for example, Japanese Patent Laid-Open No. 84092/1982).

[Problems to be Solved by the Invention] However, there is a problem in that the portions of such a resist film that are not irradiated with high-energy radiation also have relatively low resistance to dry etching typified by oxygen plasma.

An object of the present invention is to provide a resist film in which portions not irradiated with high-energy radiation are resistant to dry etching, typically oxygen etching.

[Means for Solving the Problems] The present invention is based on a polymer of (ω) at least one fluoroalkyl acrylate and at least one polymerizable substance other than the fluoroalkyl acrylate used as necessary. layer (hereinafter referred to as ω layer), and +
b) A layer having an atomic weight of 25 or more and consisting of at least one metal or metal compound selected from the group consisting of metals belonging to Ib and groups ■ to ■ and their compounds from the periodic table (hereinafter referred to as (b+ layer)) The present invention relates to a resist film formed by laminating layers of.

In the present invention, a film in which a layer of a W(CO)s plasma polymer is formed on a layer of a plasma polymer of fluoroalkyl acrylates is irradiated with an electron beam. This was made based on the discovery that the W(CO)s plus polymer layer is ablated or scattered with the addition of the W(CO)s plus polymer.

[Structure of the Invention] The fluoroalkyl acrylates used in the present invention have the general formula: A group in which one or more of these fluorine atoms is replaced by a hydrogen atom and has at least one fluorine atom, R1 is a hydrogen atom, methyl group, ethyl group, or halogen atom, and R2 is a divalent hydrocarbon residue) Examples include fluoroalkyl acrylates represented by
) for connecting the COO group and the Rt group,
The number of carbon atoms is preferably 1 to 10, particularly 1 to 5, but this is not critical. Further, preferred Rf groups of the fluoroalkyl acrylates include those in which the Rf group has 1 to 10 carbon atoms, and the number of fluorine atoms is at least the sum of the number of carbon atoms in the R1 group and 12% of the number of carbon atoms. It is 1/2.

Among the above-mentioned fluoroalkyl acrylates, preferred ones have a boiling point of 400°C or less or 40°C or less at atmospheric pressure.
The temperature is 70°C or less at Torr.

Specific examples of fluoroalkyl acrylates include co, -C(CH3)COOCH2(CF2)2NCH
2-C(C1h)COOC(CHs) 2(CF2)
2HCHs -C(CH3)COOCH2(JIFC
hCHa = C(CH3)COOCH2CF2C
HFCF3CH2-C(CH3)COOCH(CH3)
CF2 CHFCF3C)+2 = C(CH3)
COOCH(C2Hs) CF2 CHFCF3Cl
2=C(CH3)COOCH(Ca)It)CFz
CHFCF3CH2= C(CH3)COOC(CHa
)2 CF2 CHFCFICHa = C(C
H3) COOC(C)+3) (C2Hs) CF2
CHFCF3, CH2-C(CHa)COOCH2
(CF2 CF2). Hn is 2~5 CH, Tomi C(CH3)C00C(CH3)BaCF2C
F2) Hn n is 2~5 CHa = C(CH3)C00C(CHs) 2C
F2 CH(CF3) 2CHa -C(CHs) C
00C1h CH2(CF2 CF2). CF (C
F3) 2n is 1-5 CH2-C(CH3) C00CH* CH2(CF2
) Fn is 1 to 10, etc.

In the present invention, a polymerizable substance other than fluoroalkylacrylates, such as a vinyl monomer having a double bond, may be used together with fluoroalkylacrylates to form the Ca1 layer.

Regarding the usage ratio of fluoroalkyl acrylates and polymerizable substances other than fluoroalkyl acrylates, it is preferable to use fluoroalkyl acrylates in an amount of 70 to 100% (wt%, same hereinafter) based on the total amount of polymerizable substances. is used to improve adhesion and the like, and is preferred from the standpoint of maintaining the high sensitivity or high resolution that the former originally possesses, and it is more preferred to use 90 to 100%.

Specific examples of the vinyl monomer include ethylenically unsaturated olefins such as ethylene, propylene, butylene, isobutylene, and butadiene; styrene, α-
Styrenes such as methylstyrene and p-chlorostyrene; Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, and maleic anhydride; methyl niaacrylate, ethyl acrylate, n-butyl acrylate;
Isobutyl acrylate, dodecyl acrylate, n-butyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate,
Esters of α-methylene aliphatic monocarboxylic acids such as ethyl α-ethyl acrylate; vinyl methyl ether,
Vinyl ethers such as vinyl ethyl ether and vinyl isobutyl ether: Vinyl esters such as vinyl chloride, vinyl acetate, vinyl propionate, MFII vinyl, and vinyl benzoate = 1-methyl-1-methoxyethylene, 1,1-dimethoxyethylene, 1.2-dimethoxyethylene, 1.1-dimethoxycarbonylethylene-1-
Ethylene derivatives such as ditroethylene, 2N-vinylpyrrole, N-vinylcarbazole, tovinylindole,
Tovinyl compounds such as tovinylpyrrolidine and tovinylpyrrolidone; other acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, α-ethylacrylamide, acrylanilide, p-chloroacrylanilide, -m: troacrylanilide, tomethoxyacrylanilide, Examples include vinylidene chloride and vinylidene cyanide.

Typically, the ω layer is formed on a substrate on which a pattern is to be formed using the resist coating of the present invention.

(Substrates on which the aJ layer is formed include semiconductors made of silicon, germanium, etc., conductive films made of chromium, aluminum, titanium, gold, etc., and silicon oxide, phosphosilicate glass, arezenosilicate glass, borosilicate glass, etc.) Examples include insulating films such as glass.

(To form the ω layer on the substrate, for example, place the substrate in a gas flow of a low-pressure mixed gas of fluoroalkyl acrylates, a polymerizable substance other than the fluoroalkyl acrylates used as necessary, and an inert gas, The substrate is placed in a flow of a low-pressure mixed gas of an inert gas excited by glow discharge, fluoroalkyl acrylates, and polymerizable substances other than fluoroalkyl acrylates used as necessary. This may be done by a method such as the afterglow method.

As the inert gas, helium, neon, argon, krypton, and xenon can be used, and it is preferable to use argon or krypton.

Glow discharge may be performed by providing two parallel plate electrodes inside the reaction tube or by providing an induction coil outside the reaction tube and applying a high frequency voltage or current.

Regardless of the method used, such as placing a substrate in the discharge area or using the afterglow method, the
Pressure 10-10-4 Torr, preferably 1-1G
-2 Torr, for example, the flow rate of inert gas per container 11 is 0.1 to 200 m3 STP/Win, and the flow rate of monomers such as fluoroalkyl acrylates is about 0.5 to 50% of the inert gas flow bed. , especially 1~
It is preferable to supply it at a rate of about 20% by volume. Further, the glow discharge is preferably performed under a high frequency electric field of 0.1 to 1008 Hz with a discharge power of 1 to 50 ON per container 11.

The thickness of the aJ layer formed on the substrate in this way is preferably 0.01 to 10ρ, and if it is less than 0.01, it is insufficient to ablate or scatter the +a1 layer. There is a tendency for this to occur, and if the number exceeds 10, there is a tendency for it to be wasted.

In the above explanation (the ω layer was formed by a plasma polymerization method, a polymer with at least one polymerizable substance other than fluoroalkyl acrylates and fluoroalkyl acrylates used as necessary is produced, It may be formed by using a solution, applying it by a usual spin-coating method, brushing method, etc., drying it, and prebaking if necessary.

Above (on the ω layer, the periodic table Ib with an atomic weight of 25 or more,
The layer (b) is formed of at least one metal or metal compound selected from the group consisting of metals belonging to I[b and groups 1 to 2 and their compounds.

The above atomic weight is 25 or more and the periodic table Ib, IIb and ■~
Specific examples of metals belonging to group ① and their compounds include w, No, Au%Pt1M1Ti1, respectively.
Sn, Xi, Cr and W(CO)s, N1(CO
)a, No(CO)s, an(CH3)4, etc. Among these, u, No, AU%pt,
u, ++, Sn.

W (
CO)s, Sn(CH3)4, etc. are preferred.

(b) The formation of the layer is, for example, W(CO)s, N1(C
o) In the case of materials that can be vaporized, such as t, No(Co)s, etc., CVD (such as plasma polymerization method or ion blating method as explained in the case of forming the ω layer) is used. chemical Val)erdep
For example, MlA
u, Pt, No, H, an, Xi, Cr, T
When using materials that are difficult to vaporize, such as metals such as i, PVD (1) MSi
It may be formed by the Cal VaElerdepos+tton) method or the like.

The thickness of layer (b) thus formed is 5.
Preferably 0-2000 people, 100-100
More preferably, it is 0A. (The thickness of the bt layer is 5
When the thickness is less than 0 A, the resistance to dry etching such as oxygen plasma becomes low, and when the thickness exceeds 2000, it tends to become difficult to form a pattern (up to the ω layer) using high-energy radiation.

For example, as shown in FIG. 1, the input density layer is 0.
6111/d, has the characteristics of being resistant to oxygen plasma under conditions such as gas pressure 0.5 Pa, not being etched beyond a certain depth, and being etched by CO2 plasma under the same conditions. are doing.

The substrate on which the resist film of the present invention is formed can be exposed to high-energy radiation such as electron beams or Or can form a pattern.

The amount of high-energy radiation to be irradiated may be appropriately selected depending on the type, the type of layer (aJ layer, +b) constituting the coating, the thickness of the coating, and the like. When irradiating with electron beam,
Usually 10-4~1G-? Torr, preferably 10-
The process is carried out in a vacuum of s~10' Torr.

In the above description, a resist film consisting of a (ω layer and a (b) layer) has been described, but it is also possible to provide a total of 1 to 10 laminated sets consisting of a (ω layer and a (b) layer).

Next, as the (a) layer of the resist film of the present invention, 2°2.
An embodiment in which a polymer layer of 3,4,4,4-hexafluorobutyl methacrylate is provided and a W(CO)s plasma polymer is further provided as a layer will be described.

Using W(CO)6 (on the ω layer, e.g. a discharge layer -
13.56MHz, discharge power 10W, Ar pressure 0
．． 4Pa.

When a plasma polymer is generated under conditions of W(Co)6-Ar combined pressure of 1.3 Pa, ESCA analysis shows that WC
A layer (b) of a W(CO)s plasma polymer having a composition of 603,3NO,2 is formed.

W (CO)a plasma polymers are normally insensitive to e.g. electron beams, but surprisingly,
When present as a layer on a layer of a polymer of fluoroalkyl acrylates, the electron beam reaches the layer of polymer of -fluoroalkyl acrylates through the layer of W(CO)s plasma polymer, and the latter layer It has the property that as it is decomposed and etched by the electron beam, the former layer above it is also etched. This property can be obtained by forming a plasma polymer film using molybdenum carbonyl, nickel carbonyl, etc., or by using a vacuum evaporation method.

The same applies to the case where a thin film formed using a metal such as HOlAu, pt, /J, or Xi or an inorganic compound thereof is used.

When dry etching such as oxygen etching is performed on the resist film irradiated with the high-energy discharge beam thus obtained, the portion where the (b) layer does not exist (the portion where the ω layer remains) is etched.

(In order to transfer the pattern to the bottom of the ω layer, it is a mountain.) After forming the pattern on the layer, etching may be performed using oxygen plasma, hydrogen plasma, argon sputtering, or the like.

(a) When only the tb> layer is formed without forming a layer and oxygen etching is performed, a W(CO)e plasma polymer having a composition of WO2,109,3NO,2 becomes WO2,1
The composition changes only to 09,3NO,2 and is hardly etched. After 10 minutes of CO2 etching, the W(CO)s plasma polymer becomes WO2.
, 803, 6NO, 3 and is etched. Therefore, it is necessary to use dry etching other than CO2 etching for the dry etching of the resist film of the present invention.

The resist film of the present invention formed and patterned in this manner can be suitably used for manufacturing semiconductor devices, magnetic bubble devices, optical application parts, video discs, and the like.

Next, the resist film of the present invention will be explained with reference to Examples.

Example 1 Using a plasma polymerization device that generates glow discharge using a dielectric coil, fluoroalkyl acrylate was prepared with 2.2, 3, 4
, 4.4-hexafluorobutyl methacrylate, discharge pressure 0.6 Pa, argon flow rate 63.5 n' S
TP/Ifn, discharge frequency 13.56MHz.

Discharge power 10W, fluoroalkyl acrylate flow rate 1.55 c113 STP/sin, contact time 5
A layer consisting of a plasma polymer of fluoroalkyl acrylate was formed on a Si-based substrate under conditions of 0 minutes, and eggplant was placed in an air flow of 0.4 Pa generated by maximizing argon suction using a vacuum pump using the same equipment. Pour into a molded flask and heat to 50°C.
Steam generated from W(Co)s heated to
A layer made of a plasma polymer of W(Co)s was further laminated under the condition that the discharge time was 30 seconds.

The thickness of the obtained fluoroalkyl acrylate polymer was about 2.2 mm, and the thickness of the W(CO)s plasma polymer was about 2.2 mm.
It was 00A.

The resulting resist film had a step difference of 3000 Å between the irradiated area and the non-irradiated area by the 100 μC/cd electron beam, and when etched with oxygen plasma, the step difference became 800 OA.

In addition, etching with oxygen plasma was performed by placing the sample on the lower plate of a parallel disk electrode (diameter 100i+e, spacing 3G+++a) with the film facing upward, and while flowing oxygen at a discharge frequency of 13.56HH2. .

Example 2 A 10% methyl isobutyl ketone solution of 2.2,3,4,4,4-hexafluorobutyl methacrylate polymer was placed on a chromium substrate at a spinner speed of 2000 rl) 16
It was coated for 0 seconds to form a film with a thickness of 0.5 Jl. Thereafter, an NI film having a thickness of 0.1 mm was deposited using a conventional method.

1o to the substrate on which the obtained resist film was formed.

It was exposed and irradiated with an electron beam of μC/d to obtain 36 line-and-space patterns, and etched under the same conditions as in Example 1.

The step difference was 0.55ρ. Observation was made using an optical microscope with a magnification of 400 times, and it was confirmed that the substrate was etched.

[Effects of the Invention] When the resist film of the present invention in which the (bt layer is provided on the ω layer) is used, dry etching, which is difficult with conventional resist films, becomes even more possible.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between etching depth and etching time in 002 etching and Ot etching of W(CO)6 plasma polymer. Figure 71

Claims (1)

[Scope of Claims] 1 (a) a layer consisting of a polymer of at least one fluoroalkyl acrylate and at least one polymerizable substance other than the fluoroalkyl acrylate used as necessary; and (b) Periodic table Ib, IIb and III~ with atomic weight 25 or more
At least one metal or metal compound selected from the group consisting of metals belonging to Group VIII and their compounds
A resist film made of laminated layers consisting of seeds. 2 Atomic weight 25 or more and periodic table I b, IIb and III to V
2. The resist film according to claim 1, wherein the metals belonging to Group III and their compounds are W, Mo, Al, Ti, Sn, Ni, Cr, and their compounds, respectively.