Note: Descriptions are shown in the official language in which they were submitted.
0a~977Z
K- 1 8217/A
Olefinically unsaturated onium salts
The present invention relates to olefinically unsaturated onium salts, to their preparation,
to radiation-sensitive copolymers of the novel olefinically unsaturated onium salts and
copolymerisable olefinically unsaturated monomers containing an acid-labile group in the
molecule, and to the products prepared from the radiation-sensitive copolymers.
In the preparation of lithographic films, it is known to add onium salts as low molecular
compounds to the resist resin by dissolving said resin together with the onium salt in a
suitable polar solvent. The choice of solvent is relatively strictly lirnited, as the onium
salts are normally only soluble in strongly polar solvents, whereas the resist resins are
usually only soluble in weakly polar solvents. Although after stripping off the solvent the
onium salt is dissolved in the matrix resin, the danger of the formation of clusters, and
hence of the onium salt crystallising out of the resin matrix, is quite substantial, especially
if large amounts of onium salt are required or if relatively polar resist resins are used, as is
described in detail in Proceedings of the ACS Division of Polymeric Materials Science
and Engineering, Vol. 61, 1989, pages 185-188.
In DE-OS 39 02 114 there are disclosed radiation-sensitive ethylenically unsaturated
copolymerisable sulfonium salts in which the reactive double bond is attached to the
photoiniator (sulfonium salt group) through a so-called spacer, which may also contain
-OCO- groups. When used as photoresists, the copolymers obtained from such sulfonium
salts by copolymerisation with unsaturated compounds containing an acid-labile group are
still poorly light-sensitive, so that the photoresist must be irradiated at fairly high
intensities to produce images.
It has now been found that the above shortcomings can be substantially avoided by poly-
merising olefinically unsaturated onium salts which contain a spacer of different chemical
structure with copolymerisable compounds containing an acid-labile group. When used as
photoresists, the radiation-sensitive copolymers so obtained have enhanced solvent-
resistance and improved lithographic properties.
;~0~977X
- 2 -
Specifically, the present invention relates to olefinically unsaturated onium salts of
formulae I and II
R
CH2 = C--A--COO{ 3--Y~
CH2=C~CH23--O {3 Y2~ x~ (II),
wherein Rl is a hydrogen atom or methyl and A is a direct bond, phenylene or a radical
~OH2~ or tCH23~, wherein n and o are each independently of
the other an integer from 1 to 10, Y1 is -I- or $-R2 and Y2 is $-R2, wherein R2 is
Cl-C4alkyl, unsubstituted or Cl-C4alkyl-substituted phenyl, m is 0 or an integer from 1 to
10, and X is BF4, PF6, AsF6, SbF6, SbC16, FeCI4, SnF6, BiF6, CF3S03 or SbFsOH.
In formulae I and II, Rl is preferably a hydrogen atom or methyl and A is a direct bond,
phenylene or benzylene, Y1 and Y2 are each $-R2, wherein R2 is unsubstituted or methyl-
substituted phenyl, and m is 0 or an integer from 1 to 4 and X is AsF6, SbF6 or CF3S03.
More particularly, in formulae I and II Rl is a hydrogen atom and A is a direct bond, and
Yl and Y2 are each S ~9, m is 0 and X is AsF6, SbF6 or CF3S03.
Where R2 is alkyl or alkyl-substituted phenyl, the alkyl moieties may be branched or
straight-chain. Typical examples are methyl, ethyl, n-propyl, isobutyl and n-butyl.
Particularly preferred cpmpounds of forrnula I are 4-acryloyloxyphenyldiphenylsulfonium
hexafluoroarsenate, 4-acryloyloxyphenyldiphenylsulfonium hexafluoroantimonate and
2-acryloyloxyphenyldiphenylsulfonium triflate.
3 Z049~72
The compounds of formulae I and II may be prepared by reacting 1 mol of a hydroxy-
substituted onium salt of formula III
HO~Yl~ X~ (III),
wherein Yl and X are as defined for formula I, with 1 mol of an acid halide of formula IV
i 1
CH2=C-A-CO-Hal (IV),
wherein Rl and A are as defined for formula I and Hal is a chlorine, bromine or iodine
atom, in the presence of a tertiary amine, to compounds of formula I, or by reacting 1 mol
of a hydroxy-substituted onium salt of formula V
H~)~ Y2~9 X~3 (V),
wherein Y2 and X are as defined for formula II, with 1 rnol of a halogen compound of
formula VI
CH2=CH~ CH2~Hal (VI),
wherein m is as defined for formula II and Hal is a chlorine, bromine or iodine atom, in
the presence of a tertiary amine, to compounds of formula II.
Hydroxy-substituted iodonium salts of formula III are known and described, inter alia, by
F.M. Beringer and I. Lillieu in J. Am. Chem. Soc. 82 (1960), page 725 et seq.
The hydroxy-substituted sulfonium salts of formula III and V have not so far been
described in the literature and can be prepared by reacting 4-bromophenol with thiophenol
copper salt in molar amounts to 4-hydroxydiphenylsulfide, which is subsequently reacted
with molar amounts of a diphenyliodonium salt, such as diphenyliodonium hexafluoro-
arsenate, in the presence of a catalyst, such as copper(II)benzoate, to the 4-hydroxyphenyl-
- 4 -
diphenylsulfonium salt.
The compounds of formula IV are known compounds, some of which are comrnerciallyavailable. Exemplary of compounds of formula IV are acryloyl chloride, methacryloyl
chloride, 4-vinylbenzoyl chloride, 4-isopropenylbenzoyl chloride, 4-vinylphenylacetyl
chloride, 4-isopropenylphenylacetyl chloride, 4-vinylphenylpropionic acid and 4-vinyl-
phenyl-n-butyric acid.
The compounds of forrnula VI are also known compounds, some of which are cornmer-
cially available, typically vinyl chloride and vinyl bromide, allyl chlonde and allyl
bromide, and buten-1-yl chloride and buten-1-yl bromide.
Exemplary of the tertiary amines used for the preparation of the compounds of this
invention are triethylamine, benzyl dimethylamine, tributylamine, pyridine,
N,N'-dimethylpiperazine or N-methylpyrrolidone.
It is preferred to carry out the reaction in a customary organic inert solvent, such as
methylene chloride, and at room temperature or slightly elevated room temperature.
As mentioned at the outset, the novel olefinically unsaturated compounds can be
polymerised with copolymerisable compounds which contain an acid-labile group to give
radiation-sensitive copolymers v~hich can be used direct as photoresists.
Accordingly, the present invention relates to radiation-sensitive copolymers having a
molecular weight of 103 to 106, determined by gel permeation chromatogMphy,
comprising, based on the sum of the structural units present in the copolyrner of (a)
and (b),
(a) 1 to 20 mol % of the structural repeating unit of formula VII or VIII
11
A - COO ~3 Y ~ (VII) or
2~)497~2
(gH2~o _~}y ~ (VIII),
wherein Rl, A, Yl, Y2 and m are as defined in formulae I and II,
(b~ 80 to 99 mol % of a structural repeating unit of formula lX
1 3 IRs
t IC--C~ (IX),
R4 L
wherein R3 and R4 are each independently of the other a hydrogen atom, C1-C4aLkyl or
phenyl, Rs is a hydrogen atom, methyl or a halogen atom and L is a radical which contains
an acid-labile group, and
(c) 0 to 50 mol % of a structural repeating unit of formula X
IR6 IR7
C--C~ (X),
R Rg
wherein R6 and R7 are each independently of the other a hydrogen atom, unsubstituted
C1-C4alkyl or C1-C4alkyl which is substituted by halogen atoms or cyano or nitro groups,
or are unsubstituted phenyl or naphthyl or phenyl or naphthyl which are each substituted
by halogen atoms, C1-C4alkoxy, hydroxy, cyano or nitro groups, and R8 and Rg are each
independently of the other a hydrogen atom or halogen atom, unsubstituted Cl-Cl2alkyl or
C1-C12alkyl which is substituted by halogen atoms or cyano or nitro groups, unsubstituted
phenyl, naphthyl or benzyl, or phenyl, naphthyl or benzyl which are each substituted by
halogen atoms, hydroxy, cyano, nitro C1-C4alkyl or Cl-C4alkoxy groups, or are a radical
selected from the group consisting of -ORlo, -COOR1l and -COR12, wherein Rlo and R
are each independently of the other a hydrogen atom, unsubstituted Cl-Cl2alkyl or
Cl-C12alkyl which is substituted by halogen atoms or cyano or nitro groups, unsubstituted
phenyl or naphthyl or phenyl or naphthyl which are each substituted by halogen atoms,
hydroxy, cyano, nitro C1-C4alkyl or Cl-C4alkoxy groups, and Rl2 has the same meaning
204977Z
- 6-
Rl3
as Rlo and is also the radical -N~ , wherein Rl3 and Rl4 have each independently of
R14
the other the same meaning as R1o, or wherein R8 and Rg together, if R6 and R7 are a
l l
hydrogen atom, are the radical O=C- I -C=O, wherein A is a hydrogen atom, unsubstituted
A
or hydroxy-substituted phenyl or benzyl, with the proviso that the sum of the arnounts of
the structural repeating units present in ta) and (b) is 100 mol % and the amount of the
structural repeating unit present in (c) is based on said sum.
The novel copolymers preferably comprise (a) 5 to 20 mol% of the structural repeating
unit of formula VII or VIII, (b) 80 to 95 mol % of the structural repeating unit of
formula IX, and (c) 0 to 30 mol % of a structural repeating unit of formula X.
The novel copolymers preferably have a molecular weight (Mw) in the range from 5000
500 000, more particularly from 20 000 to 150 000.
In the structural repeating units of formulae VII and VIII Rl, A, Yl, Y2 and m are as
defined for formulae I and II.
The novel copolymers preferably comprise as (a) the structural repeating unit offormula VII, wherein R1 is a hydrogen atom and A is a direct bond, Y1 and Y2 are each
S ~, m is 0 and X is AsF6, SbF6 or CF3SO3.
In a preferred embodiment of the invention, the novel copolymers comprise as (b) the
structural repeating unit of formula IX, wherein L is a radical of formula XI
- 7 -
l~ IJ
~XI),
COO-C-O--R
CH
R17~ ~R
wherein Rl5 is a hydrogen atom or rnethyl, Rl6 is Cl-C4alkyl or C6-Cl2aryl and Rl7 and
Rl8 are each independently of the other a hydrogen a~om, Cl-C4alkyl or C6-Cl2aryl, and
Rl6 and Rl8, when taken together, may also be an unsubstituted or a Cl-C4aL~cyl-,
Cl-C4alkoxy-, C6-Cl2aryl- or C6-Cl2aryloxy-substituted ethylene, propylene or butylene
radical.
The novel copolymers further preferably comprise as (b) the structural repeating unit of
formula IX, wherein L is a radical of formula XII or Xl [I
~3 (Xll) ~ (Xlll),
O`CH~ \CH o - CH2--C\--/ H2
~y CH2 y) O
wherein p is 2, 3 or 4.
In a further preferred embodiment of the invention, the novel copolymers cs)mprise as (b)
the structural repeating unit of forrnula IX, wherein L is a radical of formula XIV
(XIV),
O-CO-R ,9
Z049772
- 8 -
wherein Rl9 is Cl-C4alkyl, Cl-C4alkoxy or oxyalkylene-Si-(CH3)3.
R6, R7, R8 and Rg in the structural repeating unit of formula X as alkyl may be
straight-chain or branched alkyl, preferably straight-chain alkyl.
Halogen substituents may be fluoro, chloro, bromo or iodo, preferably chloro or bromo.
Unsubstituted or substituted alkyl is typically methyl, ethyl, 2-chloroethyl, 2-nitroethyl,
n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, isoamyl, n-hexyl, 2-ethylhexyl,
n-decyl, 6-nitrohexyl or 9-bromononyl.
Substituted phenyl or naphthyl are typically o-, m- or p-chlorophenyl, o-, m- or p-tolyl,
xylyl, 2-nitrophenyl or c~-chloronaphthyl.
In the structural repeating unit of formula X, R6, R7 and R8 are preferably eachindependently of the other a hydrogen atom, Cl-C6alkyl or phenyl, and Rg is preferably a
halogen atom, phenyl or benzyl or a radical selected from the group consisting of -ORlo,
-COORIl and -CORI2, wherein Rlo, Rll and R12 are each independently of one another a
Rl3
hydrogen atom, Cl-C6alkyl or phenyl, and Rl2 is also the radical -N~ , wherein Rl3
Rl4
and Rl4 have each independently of the other the preferred meaning of Rlo.
The novel copolymers can be prepared by subjecting
(a) a compound of formula I or II and
(b) a compound of formula IXa
R3 Rs
IC= C (IXa),
R4 L
wherein R3, R4, Rs and L are as defmed for formula IX, in the molar ratio of a:b from 1:4
to 1:99, or
(c) a mixture of a compound of formula IXa and a compound of formula Xa
9 2049772
R R
6 17
l = ¦ (Xa),
R8 Rg
contained therein in an amount of up to 50 mol %, preferably of up to 30 mol%, based on
the sum of the proportions of (a) and (b) in the molar ratio of 1 :4 to 1 :99, in which formula
Xa R6, R7, R8 and Rg are as defined for formula X, to radical copolymerisation in known
manner.
The radical copolymerisation can be carried out using different techniques. These have
been described by, inter alia, S. Sandler and W. Karo in "Polymer Synthesis" Vol. 1-3,
1968, Academic Press, New York. Customary polymerisation methods are typically mass
polymerisation or solvent, emulsion, suspension or precipitation polymerisation.
Compounds of formula IXa are known. Exemplary of such compounds are thecorresponding acrylates and methacrylates,such as 4-tetrahydropyranoylphenyl meth-
acrylate, the styrene derivatives, such as 4-tert-butoxycarbonyloxystyrene, 4-acetoxy-
styrene or 4-tert-butoxystyrene, and the maleimide derivatives, such as 4-tert-butoxy-
carbonyloxyphenylmaleimide. Such compounds are disclosed, inter alia, in US patent
specifications 4 491 628 and 4 603 101; EP-A-307 356; J. Am. Chem. Soc. 72 (1950),
1200-1202, Polym. Mat. Sci. Eng. (1986),55, 608-610 and in Polym. Mat. Sci. Eng.(1989), ~, 417ff.
The compounds of formula Xa are known and some are commercially available. In
addition to olefins, such as ethylene or propylene, the vinyl compounds may be mentioned
as particular examples of compounds of formula Xa. Examples of such monomers are the
styrene types, for example styrene, a-methylstyrene, p-methylstyrene or p-hydroxy-
phenylstyrene, ~,~-unsaturated acids and esters or amides thereof, including acrylic acid,
methyl acrylate, acrylamide, the corresponding methacrylic compounds, maleic acid,
methyl maleate, maleimides or p-hydroxyphenylmaleimides, halogen-containing vinyl
compounds, such as vinyl chloride, vinyl fluoride, vinylidene chloride or vinylidene
fluoride, and vinyl esters, such as vinyl acetate or vinyl ethers, for example methyl vinyl
ether or butyl vinyl ether.
Examples of further suitable compounds are the allyl compounds such as allyl chloride,
- lo ~ 772
allyl bromide or allyl cyanide.
The polymerisation is normally initiated by one of the conventional initiators of
free-radical polymerisation. These include thermal initiators such as azo compounds,
typically azoisobutyronitrile (AIBN), or peroxides such as benzoyl peroxides, or redox
initiator systems, such as a mixture of iron(III) acetylacetonate, benzoin and benzoyl
peroxide, or photochemical free-radical fonners such as benzoin or benzil methyL~etal.
The polymerisation is preferably carried out in solution. The reaction temperature is
normally in the range from 10 to 200''C, preferably from 40 to 150C and, most
preferably, from 40 to 1 00C.
Any solvents present must be inert under the reaction conditions. Suitable solvents include
aromatic hydrocarbons, chlorinated hydrocarbons, ketones and ethers. Representative
examples of such solvents are benzene, toluene, xylene, ethylbenzene, isopropylbenzene,
ethylene chloride, propylene chloride, methylene chloride, chloroform, methyl ethyl
ketone, acetone, cyclohexanone, diethyl ether or tetrahydrofuran.
The copolymers of this invention are useful positive photoresists which have very good
light-sensitivity. In addition, the compounds obtained by acid cleavage from the novel
polymers are soluble in bases. In contrast, the preferred novel polymers are very stable to
bases, so that very good diffe;rentiation between exposed and unexposed areas is obtained
in the photoresist.
If desired, binders may also be added to the novel copolymers which, dissolved in an
organic solvent, can be used direct as photoresists.
The choice of binder is made according to the field of use and the properties required
therefor, such as the ability to develop in aqueous and aqueous alkaline solvent systems or
adhesion to substrates.
~xemplary of suitable binders c) are novolaks which are derived from an aldehyde,
preferably acetaldehyde or formaldehyde, but more particul~rly from formaldehyde, and a
phenol. I'he phenolic component of this binder is preferably phenol itself or also
halogenated phenol, for example substituted by one or two chlorine atoms, preferably
p-chlorophenol, or it is a phenol which is substituted by one to two Cl-Cgalkyl groups, for
example o-, m- or p-cresol, a xylenol, p-tert-butylphenol or p-nonylphenol. The phenol
component of the preferTed noYol3ks can, however, also be p-phenylphenol, resorcinol,
bis(4-hydroxyphenyl)meth,me or 2,2-bis(4-hydroxyphenyl3propane.
Some of the phenolic hydroxyl groups of these novolaks may be modified by reaction
with, for exarrlple, chloroacetic acid, isocyanates, epoxides or carboxylic anhydrides.
Further suitable binders are typically copolymers of maleic anhydride with styrene or
vinyl ethers or 1-alkenes.
Examples of further suitable binders are copolymers of maleic anhyd~ide with styrene or
vinyl ethers or 1-alkenes. Further binders which can be used are: homopolymeric and
copolymeric acrylates and methacrylates, for example copolymers of methyl
methacrylate/ethyl acrylate/methacrylic acid, poly(alkyl methacrylates) or poly(alkyl
acrylates), where alkyl = Cl-C20
Preferably, the binder used is an alkali-soluble substance, for example a novolak (which
may be modified as described above), poly(4-hydroxystyrene) or poly(4-hydroxy-
3,$-dimethylstyrene, a copolymer of maleic anhydride with styrene or vinyl ethers or
l-alkenes, as well as a copolymer of esters of acrylic acid or methacrylic acid with
ethylenically unsaturated acids, such as melhacrylic acid or acrylic acid.
The copolymers of this invention may contain further conventional modifiers such as
stabilisers, pigments, dyes, fillers, adhesion promoters, levelling agents, wetting agents
and plasticisers. For application, the compositions may also be dissolved in suitable
solvents.
The novel copolymers, dissolved in a solvent, have excellent suitability as coating agents
for substrates of all kinds, for example wood, textiles, paper, ceramics, glass, plastics
materials such as polyesters, polyethylene terephthalates, polyolefins or cellulose acetate,
preferably in the form of films, and also of metals such as Al, Cu, Ni, Fe, Zn, Mg or Co,
and of Si or SiO2, on which it is desired to produce an image by image-wise exposure.
The choice of solvent and the concentration depends mainly on the nature of the compo-
sition and on ~he coating method. The solution is uniformly applied to a substrate by
known coating methods, for example by whirl coating, immersion, doctor coating, curtain
2049772
- 12-
coating, brushing, spraying and reverse roller coating. It is also possible to apply the
light-sensitive layer to a temporary flexible support and then to coat the final substrate, for
example a copper-clad circuit board, by coat transfer by means of larnination.
The add-on (layer thickness) and the nature of the substrate are contingent on the desired
utility. A particular advantage of the compositions of the invention is that they can be used
in widely varying layer thicknesses. This thickness range comprises values of c. 0.1 ~,lm to
more than 10 ~lm.
Possible utilities of the novel copolymers are as photoresists in the electronics field
(galvanoresist, discharge resist, solvent resist), the production of printing plates such as
offset plates or screen printing formes, mould etching, or as microresist in the production
of integrated circuits. The possible substrates and conditions for processing the coated
substrates differ correspondingly.
Sheets made from polyester, cellulose acetate or plastics-coated papers are typically used
for the photographic recording of information. Specially treated aluminium is used for
offset formes, and copper-clad laminates are used for producing printed circuits, and
silicon wafers are used for making integrated circuits. The layer thicknesses for
photographic materials and offset printing formes are from c. 0.5 ~m to 10 llm, and for
printed circuits 0.4 to c. 2 ~Lm.
After the substrate has been coated, the solvent is normally removed by drying to give a
layer of photoresist on the substrate.
After image-wise exposure of the material in conventional manner, the exposed areas of
the photoresist are washed out with a developer.
The choice of the developer depends on the type of photoresist, especially on the nature of
the binder used or of the photolysis products. The developer may comprise aqueous
solutions of bases to which organic solvents or mixtures thereof may be added.
Particularly preferred developers are the aqueous-alkaline solutions used for the develop-
ment of naphthoquinone diazide/ novolak resists. These include in particular aqueous
solutions of alkali metal silicates, phosphates, hydroxides and carbonates. These solutions
may additionally contain minor amounts of wening agents and/or organic solvents.
;72
- 13 -
Typical organic solvents are those which are miscible with water and can be added to the
developer liquids, for example cyclohexanone, 2-ethoxyethanol, toluene acetone, as well
as mixtures of two or more such solvents.
The expression "exposure to actinic radiation in a predetermined pattern" will be
understoo{l to mean exposure through a photomask which contains a predetermined
pattern, for example a chromium mask or a photographic tlansparency, as well as
exposure to a laser beam which is moved by logic control over the surface of the coated
surface to produce an image.
The light-sensitivity of the compositions of this invention extends generally from the UV
region (ca. 250 nm) to ca. 600 nm and is thus very wide ranging. Suitable light sources
therefore comprise a large number of very widely varying types. Point light sources as
well as arrays of reflector lamps are suitable. Examples are: carbon arcs, xenon arss,
rnercury vapour lamps which may be doped with halogen atoms (metal halide lamps),
fluorescent lamps, argon glow lamps, electronic flash lamps and photographic flood
lamps. The distance between lamp and image material may vary substantially, depending
on the utility and the type of lamp, for example from 2 cm to 150 cm. Particularly suitable
light sources are laser light sources, for example argon ion lasers or crypton ion lasers.
With this type of exposure, a photomask in contact with the photopolymer layer is no
longer necessary, as the laser beam writes direct on to the layer. The high sensitivity of the
compositions of the in~ention is very advantageous here and permits high writing speeds
at relatively low intensities. This melhod can be used to make printed circuits for the
electronics industry, lithographic offset plates or relief printing plates as well as
photographic image recording materials.
The invention therefore also relates to the printing formes, printing formes, printed
circuits, integrated circuits or silver-free photographic films produced with the novel
copolymers.
Preparation of 4-hydroxydiphenyl sulfde
173 g (1 mol) of 4-bromophenol, 184.8 g (1.07 mol) of thiophenol copper salt, ~0 rnl of
pyridine and 800 ml of quinoline are charged to a 1.~ litre sulfonating flask equipped with
stirrer. ~e mixture is stirred under nitrogen at 21()C for 16 hours (h). The homogeneous
solution is cooled to c. 120C and poured onto ice/hydrochloric acid. Then 1 litre of
;~049772
- 14 -
chloroform is added and the batch is well stirred. The organic phase is separated and
washed once with 10 % hydrochloric acid. The organic phase is poured into 15 % aqueous
sodium hydroxide, well stilred, and the aqueous phase is separated and washed once with
ether.
The aqueous phase is acidif1ed with concentrated hydrochloric acid and extracted twice
with ether. The ether phase is dried, treated with activated carbon and then concentrated
by evaporation. The liquid so obtained is distilled over a Vigreux column at 0.01 mbar.
The boiling point is 115C.
The substance obtained is solid and can be crystallised from n-hexane to give colourless
needles which melt at 43.5C. 52.3 g (26 % of theory).
Elemental analysis (microanalysis):
calculated found
C = 71.26 % 71.06 %
H= 4.98 % 5.00%
S = 15.85 % 15.90 %.
The IH-NMR spectrum (CDC13) accords with the structure of 4-hydroxydiphenylsulflde.
Preparation of 4-hydroxyphenvldiphenylsulfonium hexafluoroarsenate
8 g (40 mmol) of 4-hydroxydiphenylsulflde and 18.8 g (40 rnmol) of diphenyliodonium
hexafluoroarsenate (prepared by the method described by J.V. Crivello and J.H.W. Lam in
J. Org. Chem. 43 (15), 1978, pages 3055-58), together with 0.5 g of copper(II) benzoate,
are charged to a 100 ml round flask and the mixture is stirred under nitrogen for 4 h at
130C.
The reaction mixture is cooled to 20C and ether is added. The precipitated solid is
washed thoroughly with ether and separated. The solid is dissolved in chloroform and the
solution is added dropwise to ether. The resultant oil is separated and dried under a high
vacuum at 40C, giving 9.4 g (50 % of theory) of a powder.
2049772
- 15-
Microanalysis:
calculatedfound
C= 46.17 % 46.69 %
H= 3.23 % 3.22%
S = 6.85 % 7.23 %.
The IH-NMR spectrum (acetone-d6) accords with the structure of
4-hydroxyphenyldiphenylsulfonium hexafluoroarsenate.
Preparation of 4-hydroxyphenyldiphenvlsulfonium hexafluoroantimonate
The foregoing procedure is repeated using diphenyliodonium hexa~luoroantimona
te, which is also prepared as described in J. Org. Chem. 43 (15), 1978, pages 3055-58.
Yield: 35 % of theory.
The 1H-NMR spectrum (acetone-d6) accords with the structure of
4-hydroxyphenyldiphenylsulfonium hexafluoroantimonate.
Microanalysis:
calculated found
C= 41.97 % 42.47 %
H = 2.94 % 2.96 %
S = 6.22 % 6.37 %.
Preparation of 4-hydroxyphenvldiphenylsulfonium trifluoromethanesulfonate (triflate)
The foregoing procedure is repeated using diphenyliodonium triflate, which is also
prepared as described in J. Org. Chem. 43 (IS, 1978, pages 3055-58. Yield: 48 % of
theory.
This salt can be recrystallised from n-butanol. Melting point: 143C.
Microanalysis:
calculated found
C = 53.39 % 53.40 %
H = 3.30 % 3.42 %
S = 15.00 %14.77 %.
- 16- 204~3772
The lH-NMR spectrum (acetone-d6) accords with the structure of
4-hydroxyphenyldiphenylsulfonium triflate.
Preparation of the tetrahydropyran-2-yl ester of 4-vinylbenzoic acid
20 g (135 mmol) of 4-vinylbenzoic acid and 22.7 g (270 mmol) of 3,4-dihydro-2H-pyran
are charged to a 100 ml round flask equipped with magnetic stirrer. To the suspension are
added 4 drops of concentrated hydrochloric acid, and the reaction mixture is sti~red at
40C under nitrogen. After about 40 minutes, a clear solution is obtained. This solution is
stirred for a further 40 minutes, then poured into ice-cold 2N sodium hydroxide solution.
After two extractions with diethyl ether, the ether phase is washed with water and dried
over sodium sulfate. The ether is removed on a rotary evaporator and the resultant liquid is
dissolved in n-hexane. The solution is treated with activated carbon, filtered, and the
solvent is removed on a rotary evaporator. The clear, colourless liquid is thereafter dried
under a high vacuum.
Yield: 27.5 g (88 % of theory). The substance cannot be distilled.
Elemental analysis ~microanalysis):
calculated found
C= 72.39 % 72.41 %
H= 6.94% 7.23 %
The IH-NMR spectrum (CDC13) accords with the structure of the tetrahydropyran-2-yl
ester of 4-vinylbenzoic acid.
Preparation of 4-tetrahvdropYran-2-yloxystyrene
a) In a 1 litre sulfonating flask equipped with reflux condenser, nitrogen inlet and
mechanical stirrer, 150 g (0.91 mol) of 4-hydroxycinnamic acid, 6 g (54.5 mmol) of
hydroquinone and 6 g of 1,8-diazobicyclo[5,4,0]undec-7-ene (39.4 mmol) are dissolved in
300 ml of dimethyl sulfoxide (DMSO). The reaction mixture is stirred for 4 h at
130-135C, then poured onto ice and taken up in ether. The ether extracts are washed with
S x 500 rnl of water, dried over MgSO4 and concentrated. Recrystallisation from n-hexane
gives 62.9 g (57 % of theory) of 4-hydroxystyrene with a melting point (mp) of 67.8C.
Concentration of the mother liquor gives a further 10.25 g (9.6 % of theory) of a product
which melts at 64.2C.
20~9772
- 17-
The IH-NMR spectrum (DMSO~ accords with the structure of 4-hydroxystyrene.
b) 9 g (0.125 mol) of 4-hydroxystyrene are dissolved in 120 ml of ether and 0.4 g
p-toluenesulfonic acid monohydrate in a 250 ml three-necked flask equipped with
magnetic stirrer and N2 inlet. At 5C, 11.6 g (0.1375 mol) of 3,4-dihydro-2H-pyran are
added dropwise. After 30 minutes the cooling is removed and the reaction mixture is
stirred for 20 h at room tempera~ure.
The reaction mixture is then neutralised with lN aqueous NaOH solution and the ether
phase is subsequently washed 3 times with water, dried over MgSO4 and concentrated by
evaporation, giving 23.3 g (90 % of theory) of chromatographically pure
4-tetrahydropyran-2-yloxystyrene as a colourless oil (analysis by thin-layer
chromatography), which is then polymerised direct.
The IH-NMR spectrum (CDC13) accords with the structure of
4-tetrahydropyran-2-yloxystyrene.
Example 1: Preparation of 4-acrYlovloxyphenyldiphenvlsulfonium hexafluoroarsenate
9 g (19.2 mmol) of 4-hydroxyphenyldiphenylsulfonium hexafluoroarsenate and 1.9 g of
(19.2 mmol) of triethylamine are dissolved in 36 ml of methylene chloride. Undernitrogen, 1.7 g (19.2 mmol) of acryloyl chloride are slowly added dropwise, the
temperature rising to c. 35C. The colourless solution is stirred at 25C for about 12 h.
The solution is poured onto ice, and the organic phase is washed repeatedly with water,
dried over sodium sulfate and concentrated by evaporation. The residue is dried at
30C/0.01 mbar, giving 8.1 g (81 % of theory) of a solid.
Elemental analysis (microanalysis):
calculatedfound
C=48.29 %48.30 %
H=3.28 % 3.28 %
S=6.14 % 6.33 %
F=21.82 %21.59 %
As=14.34 %13.5 %.
The IR (KBr pellet) and IH-NMR spectrum (acetone-d6) accord with the structure of
Z04977Z
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4-acryloyloxyphenyldiphenylsulfonium hexafluoroarsenate.
Example 2: Preparation of 4-acrYloyloxyphenYldiphenYlsulfonium hexafluoroantimonate
In accordance with the general procedure of Example 1, 4-hydroxyphenyldiphenylsulfon-
ium hexafluoroantimonate is reacted with acryloyl chloride. Yield of antimony salt: 51 %
of theory.
Microanalysis:
calculated found
C = 44.32 %44.95 %
H= 3.01% 3.00%
S = 5.63 % 5.74.
The IR (KBr) and IH-NMR spectrum (acetone-d6) accord with the structure of
4-acryloyloxyphenyldiphenylsulfonium hexafluoroantimonate.
Example 3: Preparation of 4-acrvloyloxyphenyldiphenvlsulfonium triflateIn accordance with the general procedure of Example 1, 4-hydroxyphenyldiphenyl-
sulfonium triflate is reacted with acryloyl chloride. Yield of triflate salt: 45% of theory.
Microanalysis:
calculated found
C = 54.77 %53.91 %
H = 3.55 % 3.67 %
S = 13.29 %12.99.
The IR (KBr) and IH-NMR spectrum (acetone-d6) accord with the structure of
4-acryloyloxyphenyldiphenylsulfonium triflate.
Example 4: eparation of 4-allyloxyphenyldiPhenYlsulfonium hexafluoroarsenate
10 g (21.4 mmol) of 4-hydroxyphenyldiphenylsulfonium hexafluoroarsenate, 38.8 g
(3.20 mmol) of 3-bromo-1-propene and 15 g of potassium carbonate are charged to 500 ml
of acetone. The mixture is stirred vigorously at 65C under nitrogen. After 18 hours the
solid is separated and the solution is freed from solvent on a rotary evaporator. The residue
is dissolved in methylene chloride, the solution is treated with activated carbon, filtered,
and the filtrate is added dropwise to diethyl ether. The precipitated colourless oil is taken
19 2049'77~
up in ethanol, treated with activated carbon and filtered. Crystallisation from ethanol gives
colourless crystals in a yield of 6.6 g (62 % of theory). Melting point: 85.6C.
Microanalysis:
calculatedfound
C=49.66 %49.69 %
H=3.77 % 3.65 %
S=6.31 % 6.27 %
F=22.42 %22.51 %
As=14.74%14.7 %.
The IH-NMR spectrum in CDC13 accords with the structure of 4-allyloxyphenyldiphenyl-
sulfonium hexafluoroarsenate.
Example 5: Copolymer I
8 g (34.4 mmol) of the tetrahydropyran-2-yl ester of 4-vinylbenzoic acid, 0.42 g(0.8 mmol) of 4-acryloyloxyphenyldiphenylsulfonium hexafluoroarsenate (APDSH),
113 mg (0.69 mmol) of o~,a'-azoisobutyronitrile (AIBN) and 32 ml of dry tetrahydrofuran
(THF) are charged to a 50 ml ampoule. At -78C the solution is freed from oxygen and the
ampoule is fused under vacuum. Polymerisation is carried out for 13 hours at 60C. The
viscous solution is addedd dropwise to methanol, whereupon the polymer precipitates. The
dried polymer is dissolved in THF and precipitated from h-hexane. The white polymer
powder is dried at 40C under a high vacuum. Yield: 5.7 g (68 % of theory).
Gel permeation chromatography (GPC) in THF:
Mw: 11 000 Mn: 4000 Mw/Mn 2.7.
Microanalysis:
calculatedfound
C = 69.9 %70.7 %
H = 6.5% 6.7%
S = 0.6 %0.5 %.
Example 6: Copolymer II
In a 25 ml round flask 8 g of freshly distilled THF, 30 mg of cc,o~'-azoisobutyronitrile are
added to 1.9 g of 4-tetrahydropyran-2-yloxy styrene (TPOS) and 0.1 g of APDSH. The
204977
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mixture is reacted for 20 h and then the solution is added dropwise to the 10-fold amount
of n-hexane. The white precipitate is freed from precipitant on the glass filter and dried
under vacuum, giving 0.48 g of a white powder.
Elemental analysis:
calculatedfound
C = 73.1 % 72.25 %
H = 7.35 % 7.38 %
S = 0.73 % 1.26 %.
GPC: Mn = 3979
Mw = 6813
Mw/~In = 1.71.
Example 7: Copolymer III
In a glass ampoule fused under vacuum, 8 g of freshly distilled THP, 19 g of (TPOS),
0.1 g of APDSH and 30 mg of cc,'-azoisobutyronitrile are heated for 20 h to 70 C. The
solution is then added dropwise to the 10-fold amount of n-hexane. The white precipitate
is freed from precipitant on the glass filter and dried under vacuum. Yield: 0.90 g.
Elemental analysis:
calculatedfound
C= 73.1% 73.1%
H = 7.3 % 7.41 %
S = 0.73 % 0.93 %.
GPC: Mn = 3116
Mw = 9635
Mw/Mn = 3.09.
Example 8 Copolymer IV
5.9 g (28.9 mmol) of 4-allyloxyphenyldiphenylsulfonium hexafluoroarsenate and 115 mg
(0.7 mmol) of AIBN are dissolved in 30 ml of THF in an ampoule. The solution is
degassed and the ampoule is fused under a high vacuum. The contents are polymerised at
65C for 17 hours. The polymer is then precipitated in methanol, dissolved once more in
THF, reprecipitated from n-hexane and dried, giving a white powder. Yield: 2.9 g (43 %
77
- 21 -
of theory).
lemental analysis:
found
C = 75.70 %
H = 7.88 %
S= 0.21%.
The elemental analysis shows that 1.5 percen~ by weight of the onium salt have been
incorporated by polymerisation.
Gel permeation chromatography (GPC) in THF:
Mw = 14 800 Mn = 9000 Mw/Mn = 1.6
Temperature gravimetric analysis (TGA): Elimination of the dihydropyran group at 233C
(onset).
Use Examples
ExamPle A
1.4 g of copolymer I according to Example S are dissolved in 7 g of cyclopentanone and
the solution is filtered through a 0.5 micron filter. This solution is applied to a silicon
wafer and a homogeneous film is produced by whirl coating. The film is dried for 2
minutes at 90C. The film thickness is 1 micron. After exposure through a mask with light
of 290 nm + 20 nm wavelength (5-8 mJ/cm2), the resist is heated for 1 minute on a hot
plate at 110C and then developed in 0.5 % aqueous sodium bicarbonate. A positive image
is obtained. Structures in the submicron ran~e are resolved.
Example B
1 part of copolymer II is dissolved in 3 parts of cyclohexanone. The filtered solution is
applied by whirl coating at 3500 rpm to a silicon wafer and then dried at 120C for 120
seconds. The resist film so obtained has a thickness of 0.8 llm. Exposure is made with a
mercury vapour larnp with narrow band interference filter (10 nm widtll, 254 nm) through
a quarz mask whose smallest structures have dimensions of 0.5 ~,lm; exposure energy:
1-20 mJ/cm2.
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Developer: 2N aqueous NaOH solution or Shipley~MF312
development time: 30-120 seconds
results: 0.5 llm structures resolved, vertical wall profile, contrast ~ = 4.0, thermal resistance >130C.
Example C
A portion of copolymer IV is dissolved in 5 parts of cyclopentanone. The solution is
applied through a 0.5 micron filter to a silicon wafer. A thin coating is applied by spin
coating at 3500 rpm and dried for 60 seconds at 120C. The resist has a layer thickness of
1 micron. The resist is exposed through a quartz mask and a 254 nm narrow band filter at
an exposure energy of 10 mJ/cm2. After exposure, the resist is heated at 90C for 100
seconds and developed in Shipley(~) MF312 development solution for about 60 seconds.
Submicron structures with vertical wall profiles can be resolved.
