JP2839172B2 - Chemically amplified photoresist containing non-metallic photosensitive acid generator - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a lithographic resist or photoresist having increased sensitivity and no metallic sensitizer. In particular, the present invention relates to a resist capable of achieving chemical amplification using a sulfonyloxyimide sensitizer that generates a strong acid by irradiating ultraviolet rays, electron beams or X-rays.

BACKGROUND ART In the manufacture of semiconductor devices, it is necessary to use a resist composition that can form an image and transfer an image pattern during a process. There is a need to increase the density of semiconductor circuits, from large scale integrated circuit (VLSI) devices to very large scale integrated circuit devices (UL
As the transition to SI increases, sub-micron photolithography (photol) can't manufacture and maintain the finest tolerances
The demand for materials useful for ithography has become important. To achieve such tolerances, chemically amplified resist systems containing polymerizable materials and acid-generating sensitizers have been developed, which increase sensitivity by using ultraviolet, electron and x-ray emission spectra. The advantage is obtained. The terms resist, lithographic resist, and photoresist are used interchangeably. Thin films of these materials are imaged at various radiation wavelengths or modes to form a pattern that is resistant to dry or wet processes as known in the art.

U.S. Pat. No. 4,102,687 discloses an ultraviolet curable organic resin composition comprising a formaldehyde and a thermosetting organic condensation resin such as urea, phenol or melamine, and a group VIa (i.e., S, Se or Te). Contains onium salts. It has been suggested to use such compositions as photoresists.

U.S. Pat. No. 4,102,747 discloses the use of polyarylonium salts of trifluoromethanesulfonic acid as photoinitiators for various cationically polymerizable organic materials. The ionic onium triflate salts disclosed herein have been shown to be useful in imageable photoresists, and the negative image is formed by a mechanism that crosslinks the epoxy novolak resin.

U.S. Pat. No. 4,371,605 discloses N-hydroxyamide and N-hydroxyamide as photoinitiators for certain photopolymerizable compositions.
The use of sulfonic esters of hydroxyimides is disclosed. The composition can then be used for patterning circuit boards and the like. The composition can be patternwise exposed to ultraviolet light having a wavelength greater than about 310 nm and produces a negative relief image upon development in acetone. A possible mechanism for such photoinitiation is that the photoinitiator cleaves upon irradiation to form the corresponding sulfonic acid, which acts as a catalyst for cationic polymerization of the polymerizable substance. Polymerizable materials include ethylenically unsaturated compositions, cyclic compositions that undergo ring opening, and polymerizable materials that undergo acid catalysis, such as melamine resins. Although polyaromatic sensitizers have been added to enhance the sensitivity of the composition, these sensitizers are too opaque at 254 nm and are not useful in deep ultraviolet applications, and are commonly used in semiconductor lithography. It does not dissolve in the aqueous alkaline developer used.

U.S. Pat. No. 4,491,628 discloses a photoresist composition comprising a mixture of a metal and metalloid type onium salt cationic photoinitiator and a polymer having an acid labile repeating pendant group. In the presence of UV light of the appropriate wavelength,
And in the presence of abstractable hydrogen, the photolysis of the onium salt generates a strong acid, which in the presence of heat cleaves the acid-labile pendant group and, concomitantly, exposes the polymer to light. Differentiate the solubility of the part in the developer. The polymers disclosed in the above patent include poly (pt-butyloxycarbonyloxystyrene) and poly (p-butyloxycarbonyloxystyrene).
-T-butyloxycarbonyloxy-α-methylstyrene). The composition can be patterned by exposure to far ultraviolet light at a wavelength in the range of about 200-300 nm. Alternatively, the addition of a polyaromatic sensitizer allows the composition to be used at longer wavelengths.

U.S. Pat. No. 4,603,101 discloses a photoresist composition comprising a cationic photoinitiator, such as a diaryliodonium salt and an arylsulfonium salt, and a polystyrene made from a t-substituted organic methyl vinyl aryl ether. Methods for increasing the sensitivity of the system to longer wavelengths are also disclosed.

U.S. Pat. No. 4,618,564 discloses a photoresist composition comprising a mixture of an aqueous alkali soluble polymer and N-sulfonyloxyimides capable of inhibiting dissolution of the polymer in an aqueous alkaline developer. Suitable polymers include novolak resins, polyethylene carboxylic acids and derivatives thereof, copolymers of styrene and maleic anhydride, and polycarbonates derived from diglycol and dicarboxylic acid. Polycyclic aromatic sensitizers can be added to enhance the sensitivity of the composition, but these sensitizers are too opaque to be useful in deep ultraviolet applications and are generally not Does not dissolve very much in the aqueous alkaline developer used.

Umehara et al., “Application of Silicon Polymer as
Positive Photo Sensitve Material "(Society of Plas
tic Engineers, Mid-Hudson Section, Technical Paper
s: Photo Polymers-Processes and Materials, 122-131
Page (1988) discloses the use of a positive working composition, which comprises a silyl ether comprising a polymer exhibiting enhanced hydrophilicity;
S-Triazine substituted with trihalomethyl and 1,3,
Contains 4-oxadiazole photoinducible acid precursor.
The use of N-phenylsulfonyloxy-1,8-naphthalimide sensitizers is also indicated, but is stated to have inferior properties to the standard or standard quinonediazide.

Onium salts with metal ions such as Ph ₃ SSbF ₆
It has a high purity and high thermal stability and gives a very sensitive resist system, but it is necessary to avoid the formation of insoluble and nonvolatile metal oxides during reactive ion etching,
In addition, there is a need for a nonmetallic sensitizer in a semiconductor manufacturing process because it is necessary to prevent metal contamination during ion implantation.

Another difficulty with onium salt sensitizers is their lack of compatibility with many resist polymers due to differences in polarity, resulting in phase separation of solid components. Onium salts also have limited solubility in many organic solvents, especially non-polar or moderately polar solvents.

In semiconductor microlithographic applications, another difficulty with onium salt sensitizers is that the photoreaction products are not soluble in aqueous alkaline developers. This leads to scumming and other undesirable properties when trying to resolve small images.

Similarly, when very non-polar sensitizers, such as polyaromatics, are used in a photoresist composition as a mixture with N-sulfonyloxyimides, these sensitizers are completely present in aqueous alkaline developers. Does not dissolve or disperse, resulting in the formation of scum. Small dimensions of the lithographic features further exacerbate scum formation because the boundary layer effect and the viscosity of the developer prevent fresh developer from flowing into submicron features. In addition, the hydrophobicity of the sensitizer reduces the rate of dissolution of the aqueous alkali-soluble portion of the resist composition, thus reducing the effective light speed.

Finally, the presence of a non-bleaching sensitizer that is very opaque to far ultraviolet light results in undesirable wall shapes and a reduction in the light speed of the resist film, which is very inconvenient in semiconductor lithographic processes.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a thermogravimetric analysis (TGA) of selected acid generators
It is a curve.

FIG. 2 is a schematic diagram of the photochemical absorption of radiation and subsequent energy transfer between photoresist components.

FIG. 3 shows poly (4-t-butyloxycarbonyloxystyrene-co-4-hydroxystyrene) (PBOCST
-PHOST, also referred to as "poly B") and trifluoromethylsulfonyloxybicyclo- [2.2.1] -hept-5
4 is an ultraviolet absorption spectrum of ene-2,3-dicarboximide (MDT).

FIG. 4 is a photomicrograph of an imaged photoresist having a profile approximately perpendicular to 1 μm lines and spaces.

DISCLOSURE OF THE INVENTION The present invention provides a resist for use in an ultraviolet, electron beam and X-ray exposure apparatus, wherein the resist has a solubility dependent on the presence of a protecting group that can be removed with an acid. Or a molecular composition and a sulfonic acid precursor that generates a strong acid when exposed to radiation. The resist composition of the present invention comprises an N-fluoroalkylsulfonyloxyimide sensitizer, a substituted or unsubstituted alkylsulfonyloxyimide sensitizer, or a substituted or unsubstituted benzenesulfonyloxyimide sensitizer, and a carbonate or carboxy. A polymer resin or a molecular monomer having a protecting group which is removed by an acid such as a rate. The sulfonic acid precursor is an N-sulfonyloxyimide of the form: In the above formula, C ₁ and C ₂ form a two-carbon structure having a single bond, a double bond, or an aromatic bond, or C ₁ and C ₂ form a three-carbon bond, that is, the imide ring has five members. a ring or a 6-membered ring, R _{represents, -C n H 2n + 1 (} n = 1~8), - C n F 2n + 1
(N = 1 to 8), camphor substituents, 2- (9,10-diethoxy _{anthracene), - (CH 2) n} -Z or - (CF _{2) n}
-Z (n = 1 to 4, Z is H, alkyl, substituted camphor,-
2- (9,10-diethoxyanthracene) or aryl), and X is selected from (m = 1 to 5), and X and Y form (1) a monocyclic or polycyclic ring which may contain one or more hetero atoms, or (2) a fused aromatic ring. (3) each independently represents H, alkyl or aryl;
(4) N-sulfonyloxyimide having the following structure, which may be bonded to another sulfonyloxyimide-containing residue or (5) bonded to a polymer chain or a skeleton, In the above formula, R 1 is H, acetyl, acetamido, alkyl having 1 to 4 carbons (m = 1 to 3), NO ₂ (m = 1
２2), F (m = 1 to 5), Cl (m = 1 to 2), CF ₃ (m =
1-2) and OCH ₃ (m = 1 to 2m), m
May be 1 to 5 in other cases, or a combination thereof, wherein X and Y form (1) a monocyclic or polycyclic ring which may contain one or more heteroatoms, or (2)
Forms a fused aromatic ring, (3) is independently H, alkyl or aryl, (4) is linked to another sulfonyloxyimide-containing residue, or (5) is linked to a polymer chain or backbone. May be.

The imide portion of the N-sulfonyloxyimide sulfonic acid precursor may also include a substituted aromatic ring,
The substituents are selected to control ultraviolet absorption properties, dissolution inhibiting or accelerating properties, thermal stability or hydrolytic stability. Among the substituted aromatic imides, among others, 3-
Nitronaphthalimide, 4-nitronaphthalimide, 4
-Chloronaphthalimide, 4-bromonaphthalimide,
There is N, N'-bis (camphor sulfonoxy) -3,4,9,10-perylenetetracarboxydiimide. The improvement in thermal stability is shown in the thermogravimetric analysis (TGA) curve shown in FIG.

It has been found that the sulfonyloxyimide sensitizers of the present invention, when used in various photoresist compositions, have increased sensitivity and are exposed under various radiation conditions. Sulfonyloxyimide sensitizers are used either mixed with the resin or bonded to the polymer skeleton, and the resin is exposed to ultraviolet light,
When exposed to electron beams, X-rays, or radiation, the composition is present in an amount such that the composition is more soluble when used in a positive mold and less soluble when used in a negative mold. Generally, the sulfonyloxyimide sensitizer will be present at about 1-20% by weight of the resin. Such a sulfonic acid precursor is preferably used in an amount of 5 to 10% by weight based on the resin.

Numerous such resins and monomers useful in the present invention that can be provided with acid-removable protecting groups are well known to those skilled in the art. For example, a novolak resin such as cresol novolak, a copolymer of p-hydroxystyrene, and methacrylic acid and its ester, and a monomer precursor thereof can be mentioned.

In a preferred embodiment, a polymer is selected that absorbs incident radiation and transfers the absorbed energy to the sulfonyloxyimidic acid generator. Polymers containing hydroxyaromatics are particularly preferred. The proposed mechanism of energy absorption and transfer is shown in FIG. Referring to this figure, a polymer having a light absorbing property in a wavelength range of exposure radiation captures a photon and shifts to an excited state. Next, the polymer in the excited state transfers an electron to N-sulfonyloxyimide to form a radical.
Form a pair of cation and radical / anion. The radical anion of N-sulfonyloxyimide is decomposed by homolysis to give an imidyl anion and a sulfonatyl radical. The sulfonyl radical then abstracts hydrogen atoms directly from the surroundings to give a protonic acid. Donor radical cations can also abstract hydrogen atoms directly from their surroundings. The resulting cation dissociates to form a proton with a neutral donor. This proton represents two equivalents of the acid and is consumed in neutralizing the imidyl anion. Compounds acting as electron donors improve the overall sensitivity by making this energy transfer thermodynamically favorable. The compound functioning as a hydrogen atom donor is
Reacts with donor radicals / cations to increase the efficiency of acid generation. Electron-donating hydroxyaromatic compounds can perform both functions and increase the overall efficiency of acid generation. Hydroxyaromatic containing polymers are examples of such electron donating hydroxyaromatic containing compounds. Further, such polymers have light absorption properties that favor absorption of ultraviolet energy in the range of about 200-300 nm. Thus, compounds containing hydroxy aromatics are particularly useful in the present invention.

The resist preparation may contain additives to enhance the sensitivity of the preparation, such as plasticizers,
Surfactants, adhesion promoters, casting solven
t), dyes, preservatives and the like, and as will be apparent to those skilled in the art, can be made positive or negative.

The following examples are provided to enable those skilled in the art to better practice the present invention, but are not limited thereto. All parts and percentages given herein are based on weight.

Example 1 Monofunctional trifluoromethylsulfonyloxydicarboximides (ie, dicarboximide triflates V, VI, VII) were prepared by Beard et al., J. Org. Chem., 38, 3673 (197
It was manufactured in the same manner as described in 3).

Addition of one equivalent of pyridine to an equivalent mixture of N-hydroxycarboximide and trifluoromethanesulfonic anhydride in methylene chloride at 0-10 ° C gives medium to high yields as shown in Table 1. Was.

Example 2 Six representative N- to common photoresist solvents
The solubility limit of the sulfonyloxyimide was determined by dissolving a small portion in propylene glycol monomethyl ether acetate (PMA) or 2-ethoxyethylpropionic acid (EEP). N- having the same imide moiety
Within the sulfonyloxyimide series, it was found that as the fluorine content of the sulfonyloxy moiety decreased, the solubility decreased in the following order. MDT is more soluble than p-fluorobenzenesulfonyloxybicyclo- [2.2.1] -hept-5-ene-2,3-dicarboximide (FBS-MD), the latter being p-methylbenzenesulfonyloxybicyclo- [ 2.2.1] -Hept-5-ene-2,3-dicarboximide (Tos-MD). Second
The table shows the solubility limits expressed in% by weight.

In the above table, PDT is trifluoromethylsulfonyloxyphthalimide and exoFBS-OD is p-fluorobenzenesulfonyloxy-exo-7-oxybicyclo-
[2.2.1] -hept-5-ene 2,3-dicarboximide.

Example 3 A. A solution of 17.4 mg of MDT was dissolved in 25 ml of acetonitrile, and 1 cm
The ultraviolet absorption spectrum was measured using a quartz cell.
Poly (4-t-butyloxycarbonyloxystyrene-co-4-bidoxystyrene) (PBOCST-PHOST,
200 mg of a solution of acetonitrile 2
It was dissolved in 50 ml, and the ultraviolet absorption spectrum was measured similarly using a 1 cm quartz cell. These spectra are
Shown in the figure. The MDT solution is 10 times stronger than the corresponding solution when dissolved in 250 ml of acetonitrile corresponding to the poly B solution, at a ratio corresponding to a typical photoresist composition.
Note that in order to directly compare the absorption of MDT and poly B, the absorption of MDT must be divided by 10 relative to the absorption shown in the figure. At the wavelength of 267 nm, poly B
Note also that MDT alone contributes less than 0.01% to the total absorption of 8% w / w MDT in the mixture.

B. Poly (4-t-butyloxycarbonyloxystyrene-co-4-hydroxystyrene) (PBOCST-PHOST,
About 20% by weight of trifluoromethylsulfonyloxybicyclo- [2.2.1] -hept-5
A photoresist preparation containing 8% by weight of ene-2,3-dicarboximide and the balance propylene glycol methyl ether acetate is coated on a silicon wafer and heated on a hot plate at 90 ° C. for 1 minute. A thin film having a thickness of about 1.1 μm was obtained. The coated wafers were each exposed to monochromatic ultraviolet light of a single wavelength selected from the values shown in Table 3. For development, it was immersed in a TMSH solution for 60 seconds as standard, and the transmitted dose was determined for each of the 13 wafers by a method well known in the art. The results are shown in Table 3.

The results of the transmitted dose data are shown in FIG. 3 and compared with the UV spectrum, it can be seen that the maximum photoresist sensitivity corresponds to the maximum absorption of the polymer containing hydroxyaromatics, and that it is at a wavelength not absorbed by the acid generator. Clearly indicated.

Example 4: Polymeric trifluoromethylsulfonyloxybicyclo- [2.2.1] -hept-5-en-2,3-di when exposed to far ultraviolet (UV) or electron beam (Eb) radiation. The conversion of the acid generator to protonic acid in a thin film containing a mixture with carboxyimide (MDT) or trifluoromethylsulfonyloxydiphenyl- (p-methylphenyl) sulfonium salt (TDPSTf) was determined. The results are shown in Table 4.

Example 5: Polymer and trifluoromethylsulfonyloxybicyclo- [2.2.1] -hept-5-ene-2,3-dicarboximide (MDT) or trifluoromethyl when exposed to far ultraviolet radiation Sulfonyloxydiphenyl- (p
-Methylphenyl) sulfonium salt (TDPSTf) was used to determine the quantum yield of the acid generator in the thin film containing the mixture. The results are shown in Table 5. Q is the quantum yield and OD is the light density.

Example 6: About 20% by weight of poly (4-tert-butyloxycarbonyloxystyrene) (PBOCST) (this is U.S. Pat. No. 4,491,62).
No. 8, the disclosure of which is incorporated by reference into the present invention), trifluoromethylsulfonyloxy-7-
Oxabicyclo- [2.2.1] -hept-5-ene-2,3-
A photoresist preparation containing 4% by weight of dicarboximide (prepared according to the method of Example 1 and referred to as ODT) and 76% by weight of propylene glycol methyl ether acetate is coated on a silicon wafer and heated at 100 ° C.
Was heated on a hot plate for 1 minute to obtain a 1.1 μm thin film. The coated wafer is opened for aperture-4 (240-280 nm).
Exposure with far ultraviolet radiation through a chrome mask on a Perkin-Elmer PE 500 exposure apparatus set to
An exposure of 8 mJ / cm ² was given. Exposed wafer at 90 ° C 9
Subjected to post exposure bake (PEB) for 0 seconds and then developed in xylene spray for 90 seconds to give a 1 μm negative image with nearly straight wall shapes.

Example 7: Poly (4-t-butyloxycarbonyloxystyrene-co-4-hydroxystyrene) (PBOCST-PHOST)
20% by weight of resin, which is prepared according to the disclosure of U.S. Patent Application No. 264,407, the disclosure of which is incorporated by reference into the present invention, and trifluoromethylsulfonyloxybicyclo- [2.2.1] -hept-5-en-2. A photoresist composition comprising 2% by weight of 2,3-dicarboximide (prepared according to the method of Example 1 and referred to as MDT) and 78% by weight of propylene glycol methyl ether acetate is coated on a silicon wafer and heated on a hot plate. Above
Heat at 70-100 ° C (preferably 70-90 ° C) for 1 minute and heat up to 0.9μ
m was obtained. The coated wafer through a chrome mask exposure with far ultraviolet radiation on Perkin-Elmer PE 500 exposure device set to aperture -4 gave exposure of 15 mJ / cm ^2. The exposed wafer is subjected to post-exposure bake (PEB) at 90 ° C. for 90 seconds, followed by phenomena in tetramethylammonium hydroxide (TMAH) aqueous solution for 60 seconds to produce a 1 μm positive image with nearly straight sidewalls. Obtained.
FIG. 4 shows the obtained image. Trifluoromethylsulfonyloxy-7-oxabicyclo- [2.2.1] -hept-5-ene-2,3-dicarboximide, trifluoromethylsulfonyloxysuccinimide (SDT) and two triflate groups per molecule Containing bifunctional compounds such as N, N'-bistrifluoromethylsulfonyloxy- (3-methyl-4,5-imidocyclohex-3-enyl) succinimide were imaged in a similar manner.

Example 8: The sensitized resist material of the present invention is also sensitive to electron beam exposure. The preparation of Example 6 (PBOCST and ODT) was heated at 100 ° C. for 1 minute, imaged at an electron point energy of 25 KeV at a dose of ² μC / cm ² and then PEB at 90 ° C. for 90 seconds.
And developed for 30 seconds in xylene spray. A high resolution negative image was obtained.

Example 9: trifluoromethylsulfonyloxybicyclo- [2.
2.1] -Hept-5-ene 2,3-dicarboximide (MD
T) A preparation consisting of 2% by weight, 5% by weight of bisphenol A-di-t-butyl carbonate, 20% by weight of novolak resin and 73% by weight of propylene glycol methyl ether acetate was coated on the wafer to give a 1.2 μm thin film. Coated far and UV exposure of the wafer in UV2 (240 to 260 nm), giving a dose of 10 mJ / cm ^2, followed by 90 seconds at 90 ° C. PE
B was performed and developed in TMAH for 60 seconds to obtain 0.5 μm and 1 μm lines in positive mode.

Example 10: Poly (4-tert-butyloxycarbonyloxystyrene-co-4-hydroxystyrene) (PBOCST-PHOST) 2
0% by weight (prepared by the method described in U.S. Pat. No. 264,407), 0.75-1.0% by weight of N-trifluoromethylsulfonyloxyphthalimide (PDT) A photoresist preparation consisting of and a balance of propylene glycol methyl ether acetate was prepared, spin-coated on a silicon wafer at 4500 rpm, and heated on a hot plate at 90 ° C. for 1 minute to form a thin film having a thickness of 0.9 to 1.1 μm. I got The coated wafer through a chrome mask exposure with far ultraviolet radiation on Perkin-Elmer PE 500 exposure device set to aperture -4 gave dose 8~10mJ / cm ^2. The exposed wafer was subjected to post-exposure bake (PEB) at 90 ° C. for 90 seconds, followed by development in a TMAH aqueous solution for 60 seconds. 1 μm images with nearly vertical sidewalls were obtained.

Example 11: Poly (4-tert-butyloxycarbonyloxystyrene-co-4-hydroxystyrene) (PBOCST-PHOST) 2
0% by weight, N-trifluorosulfonyloxydiphenylmaleimide (DPMT) 0.75 to 1.0% by weight And preparing a positive photoresist preparation containing the balance of propylene glycol methyl ether acetate and spin-coating on a silicon wafer at 4500 rpm,
Heating at 90 ° C. for 1 minute on a hot plate gave a thin film having a thickness of 0.9 to 1.1 μm. The coated wafer was exposed in a UV2, UV3 and UV4 mode with far ultraviolet radiation through a chrome mask on a Perkin-Elmer PE500 exposure apparatus set to aperture 4. This exposed wafer at 90 ° C for 90 seconds,
Post-exposure bake (PEB) was applied, followed by development in TMAH aqueous solution for 60 seconds.

 The results are as follows.

All images had nearly vertical sidewalls.

Example 12: The resist composition of Example 11 (PBOCST-PHOST and DPM
T) was prepared and spin coated on a silicon wafer as described in the example. The coated wafer was then exposed to 405 nm deep ultraviolet radiation with an h-line stepper, 40 mJ / cm
^Two exposure doses were given. The exposed wafers are
Post-exposure bake (PEB) for 0 seconds followed by development in aqueous TMAH for 60 seconds resulted in a 1 μm positive image with nearly vertical sidewalls.

Example 13: Poly (4-tert-butyloxycarbonyloxystyrene-co-4-hydroxystyrene) (PBOCST-PHOST) 2
0% by weight, N-trifluoromethylsulfonyloxyphthalimidyl ether (ODPT) 0.35 to 50% by weight And a photoresist preparation containing the remaining amount of propylene glycol methyl ether acetate, spin-coated on a silicon wafer at 4500 rpm, and heated on a hot plate at 90 ° C. for 1 minute to form a thin film having a thickness of 0.9 to 1.1 μm. I got Pe with coated wafer set to aperture 4
8-10 mJ at an average wavelength of 254 nm in UV2 mode with far ultraviolet radiation through a chrome mask on an rkin-Elmer PE 500 exposure tool
/ cm ² exposure dose. 90 ° C for this exposed wafer
For 90 seconds, followed by post-exposure bake (PEB), followed by development in a basic aqueous solution for 60 seconds. The resulting image had a width of 1 μm and substantially vertical sidewalls.

Example 14: Poly-t-butyloxycarbonyloxystyrene 20
Wt%, bistrifluoromethylbis-N, N'-trifluoromethylsulfonyloxyphthalimidylmethane (6FPDT) 0.75 to 1.0 wt% A negative photoresist preparation was prepared containing and the balance of propylene glycol methyl ether acetate. This preparation was spin-coated on a silicon wafer at 4500 rpm and heated on a hot plate at 90 ° C. for 1 minute to obtain a thin film having a thickness of 0.9 to 1.1 μm. The coated wafer was exposed to far ultraviolet radiation through a chrome mask on a Perkin-Elmer PE 500 exposure apparatus set to aperture 4 and UV
An exposure dose of 8 to 10 mJ / cm ² was given in two modes at an average wavelength of 254 nm. The exposed wafer was developed in xylene for 10 seconds to give a 1 μm image with nearly vertical sidewalls.

Example 15: Negative photoresist preparation comprising 20% by weight of poly-t-butyloxycarbonyloxystyrene (PBOCST), 0.75-1.0% by weight of N-trifluoromethylsulfonyloxydiphenylmaleimide and the balance of propylene glycol methyl ether acetate Was prepared. This composition was spin-coated on a silicon wafer at 4500 rpm and heated on a hot plate at 90 ° C. for 1 minute to obtain a thickness.
A thin film of 0.9 to 1.1 μm was obtained. Transfer the coated wafer to Perkin
-UV3 through chrome mask on Elmer PE 500 exposure tool
Exposure to deep ultraviolet radiation in mode gave an exposure dose of 100 mJ / cm ² . The exposed wafer was subjected to post-exposure bake (PEB) at 90 ° C. for 90 seconds, followed by development in xylene for 10 seconds to obtain a 1 μm image with nearly vertical sidewalls.

Example 16: N-trifluoromethylsulfonyloxymaleimide monomer was prepared according to CDBeard et al., J. Org. Chem., 38, 3673 (197
It was prepared by the method of 3) and polymerized with pt-butyloxycarbonyloxystyrene using azobisquisbutyronitrile (AIBN) as an initiator by the method described in U.S. Pat. No. 4,491,628.

The obtained polymer, poly (4-t-butyloxycarbonyloxystyrene-co-N-trifluoromethanesulfonyloxymaleimide), was spin-coated on a silicon wafer and heated at 90 ° C. for 1 minute on a hot plate. The coated wafer was exposed to far ultraviolet radiation in a UV2 mode on a Perkin-Elmer PE 500 exposure apparatus, and a dose of 25 m
J / cm ² was given. The exposed wafer was subjected to post-exposure bake (PEB) at 90 ° C. for 90 seconds. Development in aqueous alkali gave a 1.25 μm positive image.

Example 17: Poly (maleic anhydride-styrene) copolymer is reacted with hydroxyamine hydrochloride in pyridine to give the corresponding N
-A hydroxyl maleimide-styrene copolymer was formed. Then the copolymer Was reacted with triflic anhydride to produce poly (N-trifluoromethylsulfonyloxymaleimide-co-styrene). A photoresist preparation comprising 20% by weight of poly (t-butyloxycarbonyloxystyrene (PBOCST), 8% by weight of poly (N-trifluoromethylsulfonyloxymaleimide-co-styrene) and 72% by weight of propylene glycol methyl ether acetate was prepared. This composition was spin-coated on a silicon wafer and heated on a hot plate at 90 ° C. for 1 minute to obtain a 0.8-1.0 μm thin film.The coated wafer was exposed to Perkin-Elmer PE 500 exposure Exposure with deep ultraviolet radiation in UV2 mode through a chrome mask on the device,
A dose of 20-25 mJ / cm ² was given. 90% on this exposed wafer
A post-exposure bake (PEB) at 90 ° C. for 90 seconds followed by development in anisole provided a good transfer image on the substrate.

Example 18: AN-trifluoromethylsulfonyloxybicyclo-
[2.2.1] An epoxide-containing sensitizer is obtained by oxidizing -hept-5-ene-2,3-dicarboximide (MDT) at 0 ° C. with metachloroperoxybenzoic acid in methylene chloride. Prepared. Purified by chromatography (silica gel, hexane: ethyl acetate 2: 1). According to hydrogen and carbon NMR, infrared spectrum and ultraviolet spectrum, the obtained substance was identified as N-trifluoromethylsulfonyloxybicyclo- [2.2.1] -heptane-5,6-oxy-2,3-dicarboximide (EXMDT ).

B. Poly (4-t-butyloxycarbonyloxystyrene-co-4-hydroxystyrene) (PBOCST-PHOST) 2
A positive resist preparation was prepared containing 0% by weight, 2% by weight of the epoxy sensitizer (EXMDT) prepared above and the balance of propylene glycol methyl ether acetate. 3000 rp of this resist preparation on silicon wafer
m, and dried on a hot plate at 90 ° C. for 1 minute. The coated wafer was averaged on a Perkin-Elmer PE500 exposure apparatus with aperture 4 set to an average wavelength of 254 nm.
And exposed to a dose of 6-8 mJ / cm ² .
Post-exposure bake (PEB) on the exposed wafer at 90 ° C for 90 minutes
, Followed by development in a basic aqueous solution,
A pattern having a line width and an interval of 1 μm having substantially vertical side walls was obtained.

Surprisingly, the photosensitivity of the sulfonyloxyimide (triflate) compositions of the present invention is enhanced by using a sensitizer that is sufficiently transparent between 200-300 nm and has an absorbance preferably below 0.8. It has been found possible. It is considered that these sensitizers have an electron transfer mechanism from the sensitizer to the triflate receptor. Poly (4-t-butyloxycarbonyloxystyrene-co-4-hydroxystyrene) (PBOCST-PHOS
T) When used with a resist composition, among substituted benzene compounds, hydroquinone, resorcinol, pyrogallol, bisphenol A, 2,6-di-t-butyl-
4-Methylphenol, 3,3 ', 5,5'-tetra-t-butylbisphenol A, and aromatic phenols such as methylenebishydroquinone and 2,5-di-t-butylhydroquinone are bicyclo- [2.2. 1] -Hept-5-ene-2,3-dicarboximide triflate has been found to enhance. It is believed that after photolysis of the N-O bond of the triflate, the phenolic compound enhances the formation of triflate acid during the chemically amplified exposure step. An additional benefit of aromatic phenols is the increased sensitivity of triflate to electron and x-ray exposure.

Example 19: 20% by weight of poly (4-tert-butyloxycarbonyloxystyrene-co-4-hydroxystyrene) (BCOS-PHOS), N-trifluoromethylsulfonyloxybicyclo- [2.2.1] -hept-5 A resist preparation comprising 2% by weight of ene-2,3-dicarboximide (MDT) and 2% by weight of hydroquinone increases sensitivity at least 2 times for X-ray exposure and 1.5 times for electron beam exposure It was shown that. Table 6 shows a comparison between a photoresist with such an additive and a photoresist without the additive.

Example 20: Poly (4-tert-butyloxycarbonyloxystyrene) (PBOCST) 20% by weight, N-pentafluorobenzenesulfonyloxybicyclo- [2.2.1] -hept-5-
A resist preparation containing 2% by weight of ene-2,3-dicarboximide and 2% by weight of hydroquinone and 71% by weight of propylene glycol methyl ether acetate was prepared, as was a resist without hydroquinone. When forming a negative image in UV2 by imaging and development, the resist containing hydroquinone 50 mJ / cm ²
It was noticed that a 1 μm image was resolved by the method, while a resist containing no hydroquinone required a dose of 100 mJ / cm ² .

Example 21: An alkali-soluble basic resin such as p-hydroxystyrene can be developed with a base in combination with a crosslinking agent such as an alkoxylated methamine formaldehyde or urea formaldehyde resin and the triflate sensitizer of the present invention. A negative resist can be prepared. About 15% p-hydroxystyrene, alkoxylated urea formaldehyde 5
%, MDT 2% and propylene glycol methyl ether acetate 78% form a fine negative image in ultraviolet, electron and X-ray radiation, which is due to the cleavage of the alkoxy group from the urea formaldehyde skeleton and subsequent This is because cross-linking with p-hydroxystyrene occurs in the exposed region.

Example 22: N-Camphorsulfonyloxynaphthalimide: 4.7 g of sodium salt of N-hydroxynaphthalimide, 5.0 g (±) of camphorsulfonyl chloride, and a small amount of 18-crown-6 crystals were added to 100 ml of glyme, And stirred in N ₂ overnight. The next day, the solution was refluxed, filtered while hot through diatomaceous earth, and the filter cake was washed with additional hot grime. The solvent was evaporated and the product was recrystallized from toluene / heptane, filtered, washed with cold toluene, then with heptane, suction dried and placed in a vacuum oven at 50 ° C. Pale yellow crystals 8.
2 g (96.5%) were obtained.

Example 23: N-trifluoromethanesulfonyloxy-1,8-naphthalimide: 23.5 g of sodium salt of N-hydroxy-1,8-naphthalimide and 28.2 g of triflateic anhydride were added to 250 ml of chloroform and stirred at room temperature overnight. did. The next day, an additional 250 ml of chloroform was added, the reaction was refluxed, then filtered through dicalite and crystallized. 23.5 g (68.1%) of pale yellow crystals were obtained.

Example 24: N-Camphor sulfoneoxy-3-nitro-1,8-naphthalimide (one-pot method): 4.9 g of 3-nitro-1,8-naphthalic anhydride and 1.5 g of hydroxylamine hydrochloride in 100 ml of dry pyridine added. After stirring for 2 hours, the reaction was refluxed and 20 ml of pyridine were distilled off. The reaction was cooled to room temperature, 5.0 g of camphorsulfonyl chloride was added, and the reaction was stirred at room temperature overnight. The reaction was poured over about 500 ml of crushed ice. When the ice was almost thawed, the mixture was filtered, the solid was washed with water and sucked dry. The solid was recrystallized from cyclohexanone to give 4.5 g of orange crystals.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to only the compositions disclosed herein, but includes all of the scope of the present invention defined by the following claims. The right to amendments is reserved.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventors Deputro, Richard, Ansonny, Mount Holly Drive, San Jose, California, USA 6682 (72) Inventors Ito, Hiroshi Echo Ridge Drive, San Jose, California, USA 7149 (72) Inventor Nose, Christopher, John W. Brock, New Jersey, USA. Meadow Drive 934 (72) Inventors Wong, Raniy, Wyrin Wapping Guards Falls, New York, USA Mina Drive 31 (72) Inventors Miura, Steve, Seichi Poughkeepsie, New York, United States Arda Drive 97 (72) 72) Inventors Monte Gomelii, Melvin, Warren Maneuche Drive, New Unser, New York, United States of America 23 (72) Inventors Morrow, Waine, Martin Wapping Guards Falls, New York, United States of America Rideia Drive (no address) (72) Invention Authors Seitchdev, Harvans, Swig Wapping Gards Falls, NY, United States Tanglewood Drive 14 (72) Inventors Welsh, Kevin, Michael Phil, New York, USA Skill, Green Hill Drive 9 (56) References JP-A-60-260947 (JP, A) JP-A-61-166544 (JP, A) JP-A-2-100054 (JP, A) JP-A-3 -206458 (JP, A) JP 2-27660 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03F ^7/ 00-7/18

Claims (5)

(57) [Claims] 1. A polymer or molecular composition, the solubility of which depends on the presence of an acid-removable protecting group, and (b)
A sulfonic acid precursor that generates a strong acid when exposed to radiation, including a sulfonic acid precursor that does not contain metal ions, is a photoresist for use in an ultraviolet ray, an electron beam, or an X-ray exposure apparatus, wherein the sulfonic acid precursor is as follows: Is a sulfonyloxyimide having the structural formula: In the above formula, C1 and C2 is a single bond, double bond, 3 to form a carbon structure or an aromatic bond,, R _{is, (1) -C n H 2n} + 1 (n =
1~8), (2) - ( CH 2) n -Z (n = 1~4, Z is H, alkyl, aryl, camphor substituents or 2- (9,
10-diethoxyanthracene)), (3) substituted camphor,
Or (4) Here, R 1 is H, acetyl, acetamide, alkyl having 1 to 4 carbons (m = 1 to 3), NO ₂ (m =
1), Cl (m = 1 to 2), and OCH ₃ (m = 1 to 2), where m is 1 to 5 in other cases, and X and Y are (1) 0 A single or multiple ring containing one or more heteroatoms, (2) a fused aromatic ring, (3) each independently H, alkyl or aryl, (4 ) Is bound to another sulfonyloxyimide-containing residue, or (5)
A photoresist, wherein the photoresist is bound to a polymer chain or backbone. 2. The photoresist of claim 1, wherein said sulfonic acid precursor is present in an amount of 1 to 20% by weight of the composition. 3. The method according to claim 1, wherein the sulfonic acid precursor is 3-nitronaphthalimide, 4-nitronaphthalimide, 4-chloronaphthalimide, 4-bromonaphthalimide, and N,
2. The photoresist of claim 1, wherein the photoresist is a sulfonyloxyimide having an imide moiety selected from the group consisting of N'-bis (camphorsulfonoxy) -3,4,9,10-perylenetetracarboxydiimide. . 4. The photoresist of claim 1, wherein the polymer or molecular composition contains a hydroxy aromatic group. 5. A polymerizable or molecular composition whose solubility depends on the presence of an acid-removable protecting group, and a metal ion-free sulfonic acid precursor which generates a strong acid when exposed to radiation. Wherein the sulfonic acid precursor is a sulfonyloxyimide having the following structural formula: In the above formula, C1 and C2 is a single bond, double bond, 3 to form a carbon structure or an aromatic bond,, R _{is, (1) -C n H 2n} + 1 (n =
1~8), (2) - ( CH 2) n -Z (n = 1~4, Z is H, alkyl, aryl, camphor substituents or 2- (9,
10-diethoxyanthracene)), (3) substituted camphor,
Or (4) Here, R 1 is H, acetyl, acetamide, alkyl having 1 to 4 carbons (m = 1 to 3), NO ₂ (m =
1), Cl (m = 1 to 2), and OCH ₃ (m = 1 to 2), where m is 1 to 5 in other cases, and X and Y are (1) 0 A single or multiple ring containing one or more heteroatoms, (2) a fused aromatic ring, (3) each independently H, alkyl or aryl, (4 ) Is bound to another sulfonyloxyimide-containing residue, or (5)
Applying a layer of a photoresist composition to the substrate, wherein the layer is bonded to a polymer chain or backbone; and (b) exposing the layer to ultraviolet, electron or x-rays to form a latent image (C) heating the layer to chemically cleave the acid-removable protecting groups in the latent image areas; and (d) selectively removing a portion of the photoresist composition. Dissolving to form a relief image. A method of forming a photoresist relief image.