JPS58113932A - Resist material and formation of resist micropattern using it - Google Patents

Abstract

PURPOSE:To form a resist micropattern improved in adhesion to a base without deteriorating sensitivity and resolution, by irradiating a resist film of a copolymer of fluoroalkylacrylate and acrylamide with high energy rays. CONSTITUTION:A resist micropattern is formed by copolymerizing (A) fluoroalkyl acrylate of formulaI(R1 is optionally halogenated methyl or ethyl, halogen or H, R2 is 1-6C divalent hydrocarbon group, and Rf is 1-15C fluorinated alkyl), such as formula II, and (B) acrylamide of formula III (R3 is H, methyl, ethyl, or the like), such as methacrylamide, irradiating a resist film made of this copolymer with high energy rays, such as electron beams, and developing it.

Description

[Detailed Description of the Invention] Regarding a mold resist material and a method for forming a fine resist pattern using the same - Conventionally, photoresists that use visible light or near ultraviolet rays have been used as pattern forming materials in technical fields such as masking and semiconductor manufacturing. Such a resist was sufficient to create an opening on the order of several Par.
However, in recent years, as electronic components have become lighter and larger in capacity, patterns have become increasingly finer, and there has been a need for openings on the order of several micrometers or smaller, particularly 1 micrometer or smaller.

In order to form such fine patterns on the order of several μm or sub-electrons, conventional 7-oscilloscope resist materials cannot be used, so high-energy rays such as short-wavelength deep ultraviolet rays and XA1 electron beams are used. The resist material used was developed, and submicron order [
It has become possible to form a d pattern.

Polymethacrylate, below C, PMM is widely used as such resist material.
There is a). PMMA has very high resolution but low sensitivity (for example, soft
1300 mJ/am'' for xJIII, and I x 10-'O/am2 for electron beam), but it takes a long time to form 1.

In addition, attempts have been made to use certain polyfluoroalkyl methacrylates as resist materials for high-energy rays (see Japanese Patent Publication No. 55-24088).
Although these resist materials have improved sensitivity, which is a drawback of PMMA, when developing certain types of substrates such as silicon, the developer solution penetrates between the resist pattern and the resist pattern may peel off or the pattern may rise, and as a result, the dimensions of the blade pattern on the substrate obtained by etching etc. may become larger than the specified dimensions.
There is a problem due to poor adhesion, which causes a decrease in accuracy. In some cases, such defects cannot be sufficiently recovered even by post-baking.

The present inventors conducted extensive research to overcome the drawbacks of these conventional resist materials, and as a result, we found the following formula: a group substituted with a halogen atom,
Represents a halogen atom or a hydrogen atom, R2 has 1 carbon number
fluoroalkyl acrylate represented by the general formula (■): 3 0H2=0 1(I) A copolymer obtained by copolymerizing acrylamide represented by the formula C (in which R3 represents a hydrogen atom, a methyl group, or an ethyl group) exhibits high sensitivity and resolution. It has been found that the resist material has excellent adhesion properties and is an excellent positive resist material for forming fine patterns.

Specific examples of the compound represented by the general formula (I) include those represented by the following chemical formula.

OH2:O(OH3)OOOGH2GIF20HF20
H2=O(OH3)0900H2(IF,OF,Oν2
C! 2(%=O(OH3)OOOOOH2a1P2OFU
FOF30) 13 0H2=CI (Town 10000H2C) I20'? 20F
g (7F.

0H2= O(OH, +ooooH2au2(oy, c
yir,)2cyy.

The ratio (molar ratio) of the compound represented by general formula (I) and the compound represented by general formula (1) in the copolymer according to the present invention is 60:40 to 99.9:0.1.
, Nakazu < 80 j 20~99.9 + 0.1
It is preferable that The adhesion of the copolymer is expressed by the general formula fl
) The higher the proportion of compounds represented by ), the higher the improvement, but the sensitivity and resolution decrease.

Within the above ratio range, the sensitivity and resolution do not deteriorate to the extent that they become a practical problem, and the adhesion is also within a sufficient range. In addition, the weight average molecular weight is 10,000 to 20.000.0
00. a9 is so, ooo~1o, ooo,
cioo is used. The higher the molecular weight, the greater the difference in the rate of dissolution in the solvent between the irradiated portion and the non-irradiated portion of the high-energy rays, resulting in improved sensitivity and resolution.

The copolymer used in the present invention can be produced by bulk polymerization, solution polymerization, emulsion polymerization, or suspension polymerization of a compound represented by general formula (I) and a compound represented by general formula (1) in the presence of a conventional polymerization catalyst. This can be carried out by copolymerization using any polymerization method such as polymerization.

The degree of polymerization can be adjusted by a conventional method by changing the amount of polymerization catalyst added, reaction temperature, etc.

The method for forming the resist film of the copolymer on the substrate is carried out by a general resist film forming method. That is, the copolymer is dissolved in a solvent such as an aliphatic ketone, an aliphatic alcohol, an aliphatic ester, an aliphatic ether, an aromatic hydrocarbon, an alicyclic ketene, a hacegenated hydrocarbon, or a mixture thereof to prepare a resist solution. A resist film can be formed by coating the resist solution on a substrate using a spin coater or the like, and then completely evaporating the solvent by air drying, heating drying, or the like.

The substrate used is not particularly limited, and various substrates such as a chrome mask substrate, silicon, nitric oxide, silicate glass, silicon titanium, aluminum, titanium, and gold can be used in the present invention, and any substrate can be used in the present invention. The resist coating seen by the invention exhibits high adhesion.

A fine resist pattern can be formed by irradiating the resist film with high-energy rays to draw a pattern, and then developing it using a developer.

The high energy beam used for pattern drawing is an electron beam, 300n! Ultraviolet rays below II, far ultraviolet rays or xI
Examples include I.

The developing solution is a solvent in which, in the resist film made of the copolymer, the dissolution rate of the part whose molecular weight has been reduced by irradiation with high-energy rays and the originally high-molecular-weight part which has not been irradiated with high-energy rays is significantly different. used.

Such solvents include one or a mixture of two or more alcohols having 2 to 8 carbon atoms, or (n)(t) alcohols having 1f to 8 carbon atoms;
, < represents a mixture of two or more types and (ii) one or two hydrocarbons having 5 to 11 carbon atoms.
Examples include mixtures of more than one species and mixtures with water. Among (B), (1) is preferably isopropyl alfur or normal propyl alcohol, and (■) is hexane, heptane, octane, nonane, benzene, cyclohexane or water. The mixing ratio of the solvents listed in (1) of (B) and the solvents listed above can be appropriately selected and determined depending on the molecular weight of the copolymer and the desired sensitivity.

Further, the developing temperature and time may be appropriately determined depending on the type of developer and the molecular weight of the copolymer.

Finally, the desired fine resist pattern is formed by drying and baking the irradiated object after development.

Next, the present invention will be explained in more detail with reference to reference examples and examples, but the present invention is not limited only to these examples.

Reference Example 1 12 parts (parts by weight, same hereinafter) of methacrylic acid chloride and 2.2. L 4.4.4-Hexafluorobutyl alcohol 60Wl, further added as a polymerization inhibitor, 90
Heated at ~100°O for 3 hours. The reaction product mixture was distilled to obtain 15 parts of 2.2.5.4.4-hexafluorobutyl methacrylate (hereinafter referred to as HIFIIMA) (boiling point = 60-6 ηQmsm).

Next, 99 parts (97.1 mole parts) of HIPBMk, 1 part (2.9 mole parts) of methacrylamide (hereinafter referred to as MAA), 0.ff part of azobis isophandronitrile (hereinafter referred to as artificial EN), and 1 part (2.9 mole parts) of decyl mercaptan 0.0
After adding and mixing 25 parts and 1 oz of methyl isobutyl ketone and degassing, the mixture was copolymerized at 60°O for 24 hours. A7ton was added to the reaction product mixture to make a homogeneous solution, and then petroleum ether was added to precipitate it, yielding 93 parts of a copolymer.

This copolymer was analyzed by pyrolysis gas tetramography, and it was confirmed that it contained 3.0 moles of MAA monomer unit and was copolymerized at a similar charging ratio.

This copolymer was made into a methyl ethyl ketone solution, and 35c
The intrinsic viscosity [η] determined by lo was 0.39. The weight average molecular weight determined by gel vermutation chromatography was approximately 550,000.

Example 1 46 parts of methyl isobutyl natone was added to 4 parts of the copolymer obtained in Reference Example 1 to prepare a uniform resist solution. The resist solution was coated onto a silicon wafer by a spin coating method so that the film thickness was 0.5 μm, and then heated at 140° for 30 minutes to evaporate the solvent, and then cooled to room temperature. After forming the resist film, each sample having the resist film was subjected to an accelerating voltage of 2DkV (current I x 10-
'A) electron beam for 0.08 seconds each (electron beam dose 1.
9 x 10-70/am2) ~125 seconds (electron dose 2
．． 9X'10-'010ffi"). These samples were irradiated with 23'0 isopropyl alcohol-n-hebutane mixed solvent (volume ratio 85:15).
) for 90 seconds to develop the resist pattern. This product was immediately immersed in n-heptane at 23°A for 60 seconds and washed.The remaining film thickness of the resist film of the resist pattern obtained by above was measured using Film Thickness Measurement 11i (Talystep C manufactured by Bopson Ltd., UK). did.

Figure 1 shows a characteristic diagram showing the relationship between irradiation time (seconds) and residual film thickness (Fml). Figure 1 shows the sensitivity of the resist i -
2X 10-'O/a+a2, r value of 2.62 can be read.

Next, an experiment was carried out in the same manner as in Example 1 except that lysine (capacity ratio 1:5) was used instead of lysine using an electron beam of 0.47 x 10-'Q/am2. As a result, the sensitivity is 2.9 x 1
0 0/am, and the γ value was 1.2.

Moreover, the adhesion was very good.

Reference example 3 2.2.5.5-tetrafluoro4-1,1-dimethylpropyl methacrylate 991Mf in place of HIFDMA
An experiment was carried out in the same manner as in Example 1, except that 1 g of acrylamide was used in place of MAA, and 0.05 part of a polymerization initiator was used.
) was obtained.

Example 4 An experiment was conducted in the same manner as in Example 1, except that the copolymer used was replaced with that obtained in Reference Example 3.

As a result, the sensitivity was 2. OX 10°'O/am2,
The r value was 1.4. Moreover, the adhesion was very good.

[Brief explanation of drawings]

Figure 1 shows the relationship between the electron beam irradiation time and the remaining film thickness.The resist pattern was drawn with an AND space of 2.3 and 5 μm, and was similarly developed, washed, and dried, and was observed using an optical microscope at 400x magnification. The density was evaluated. As a result, it was observed that all patterns were completely adhered @Example 2 The isopropyl alcohol-n-hebutane mixed solvent used as the developer was replaced with isopropyl alcohol containing 1.25% water. In addition, the experiment was conducted in the same manner as in Example 1. As a result, the sensitivity was I x 10-6010!
! +2, and the r value was 2.0. Moreover, the adhesion was very good. Reference example 2 The amount of HFEMA used is 90 parts, and the amount of MMA used is 1 part.
The experiment was carried out in the same manner as in Reference Example 1 except that part 0 was used,
A copolymer was added. Example 3 Copolymer t used - It is a characteristic diagram showing the developer solution isopropyl alcohol-n-oct in place of the one obtained in Reference Example 2. Patent Applicant Daikin Industries, Ltd. 1 Figure R So 8 Imma (Seconds) Continued from Page 1 0 Inventor Hiroshi Asayo 162 Shirakata Shirane, Tokai-mura, Naka-gun, Ibaraki Prefecture Nippon Telegraph and Telephone Public Corporation Ibaraki Telecommunications Research 0 in-house inventions Author: Kogure Ibaraki Prefecture, Naka-gun, Tokai-mura, Shirakata-za Shirane 162, Nippon Telegraph and Telephone Public Corporation, Ibaraki Telecommunications Research Institute ■Applicant: Nippon Telegraph and Telephone Public Corporation-35'/

Claims (1)

[Scope of Claims] 1 General formula (I): 1 (wherein R is a methyl group, an ethyl group, or a snow group. A group in which at least one of these hydrogen atoms is substituted with a halogen atom, a halogen atom, or hydrogen represents an atom, R2 represents a divalent hydrocarbon group having 1 to 6 carbon atoms, and R
2 represents an alkyl group having 1 to 15 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom) and a fluoroalkyl acrylate represented by the general formula (I)
A resist material comprising a copolymer with acrylamide represented by: 3 (wherein R3 represents a hydrogen atom, a methyl group, or an ethyl group). 2. The molar ratio of the fluoroalkyl acrylate represented by the general formula (1) to the acrylamide represented by the general formula (II) is 60? 40-99.9:0.
1. The resist material according to claim 1, comprising a copolymer of 1. 5 The molar ratio of the fluoroalkyl acrylate represented by the general formula (1) to the acrylamide represented by the general formula (1) is 80! 20~99.9 +0.1
The resist material according to claim 1, comprising a copolymer. 4 The weight average molecular weight of the copolymer is 10,000 to 2
0,000.000. The resist material according to claim 111f1, 2 or 3. 5 The weight average molecular weight of the copolymer is 50.000 to 1
Claims 1 and 2 which are 0,000.000
A resist material according to item 1 or item 1113. 6 General formula (1): (wherein, R represents a methyl group, an ethyl group, or a group in which at least one of their hydrogen atoms is substituted with a halogen atom, a halogen atom, or a hydrogen atom, and R2 represents a carbon a divalent hydrocarbon group having 1 to 6 carbon atoms, and R1 represents an alkyl group having 1 to 15 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom); A resist consisting of a copolymer obtained by copolymerizing acrylamide and acrylamide represented by the general formula (phantom; (7H2 = 0 1 (■) A method for forming a fine resist pattern, characterized in that the film is irradiated with high-energy rays and then developed.
7. The method for forming a fine resist pattern according to claim 6, which is carried out using I or a mixture of two or more types as a developer. 8 The development is made from (1) one or a mixture of two or more N alcohols having 2 to 8 prime numbers and (1) one or a mixture of two or more hydrocarbons having 5 to 11 carbon atoms or water. 7. The method for forming a shoe resist pattern according to claim 6, which is carried out using a mixture of the following as a developer. 9. Claim No. 9, wherein the development is carried out using a developer mixture consisting of (1) isopropyl alcohol or normal tetrapyl alcohol and (fl) hexane, heptane, octane, nonane, benzene, cyclohexane, or water. Method 0 of forming a fine resist T pattern as described in Section 6