A radiation-sensitive composition comprising a radiation-sensitive polymer which has in its molecule a plurality of epoxy groups and a plurality of bromine atoms, and at least one stabilizer which is selected from the group consisting of compounds having stable free radicals, polymerization inhibitors, ketone-amine reaction products, and phenol derivatives. Even when the composition is preserved for a long term, the characteristics do not change.

BACKGROUND OF THE INVENTION 
This invention relates to improvements in an organic polymeric material 
which exhibits a high sensitivity and a high contrast characteristic to 
radiations such as electron beams, ion beams, .gamma.-rays, neutron beams 
and X-rays. More particularly, it relates to a novel composition free from 
instability. 
The term "instability" is intended to mean the insolubility (spontaneous 
insolubilization) of unirradiated parts of the polymeric material. 
As is well known, electron beam-sensitive organic polymers are noticed as 
materials to replace photosensitive resins and are being put into 
practical use as, for example, resist materials. The resist materials are 
broadly classified into a photo resist exploiting photosensitivity, and an 
electron-beam resist exploiting electron-beam sensitivity. A deep-UV 
resist, an X-ray resist or the electron-beam resist is noticed in that a 
precision working is possible. 
Some of the inventors have previously proposed as a material of this type a 
radiation-sensitive material which comprises a polymeric material having a 
plurality of epoxy groups and a plurality of bromine atoms in one molecule 
thereof (Japanese Patent Application No. 51-16029, corresponding U.S. 
Patent Application Ser. No. 768,728 filed on Feb. 15, 1977). 
This radiation-sensitive material is made of at least one polymeric 
material selected from the group consisting of brominated and epoxidized 
polymers of butadiene, brominated and epoxidized copolymers of butadiene, 
brominated and epoxidized polymers of isoprene, brominated and epoxidized 
copolymers of isoprene, brominated products of copolymers of butadiene 
with addition-polymerizable compounds containing an epoxy group, 
brominated products of copolymers of isoprene with addition-polymerizable 
compounds containing an epoxy group and epoxidized products of copolymers 
of one of butadiene and isoprene with addition-polymerizable compounds 
containing a bromine atom. 
The polymeric materials can be produced by subjecting a polymer or 
copolymer containing a plurality of carbon-to-carbon double bonds in one 
molecule, such as polybutadiene, polyisoprene, a butadiene copolymer or an 
isoprene copolymer, to addition of bromine and epoxidation in succession 
or simultaneously, or by subjecting a copolymer of a diene compound with 
an epoxy group-containing, addition-polymerizable monomer to bromination. 
The procedures for producing these polymeric materials, as well as the 
characteristics of these materials, are described in greater detail in the 
heretofore mentioned application Ser. No. 768,728, the disclosure of which 
is incorporated by reference. 
The polymeric materials have high sensitivity, high resolution and high 
contrast characteristics as the radiation-sensitive materials. Owing to 
the high sensitivity, they are useful as recording materials in the field 
of recording information. 
An example of the case of employing the radiation-sensitive materials as 
electron-beam resists will be explained with reference to FIGS. 1-A to 
1-C. 
As shown in FIG. 1-A, a metallic evaporated film 2 is formed on a glass 
substrate 1, and a coating film 3 of the radiation-sensitive material is 
formed thereon by applying a resist solution containing the 
radiation-sensitive material and an appropriate solvent. A part of the 
coating film 3 is irradiated by an electron beam 4 in a suitable dose, 
whereupon the coating film is treated with a proper organic solvent 
(liquid developer). Then, that part of the coating film which has not been 
subjected to the irradiation by the electron beam is dissolved and 
removed, and only that part of the coating film which has insolubilized 
owing to the irradiation by the electron beam remains without being 
dissolved in the solvent, so that a state illustrated in FIG. 1-B is 
attained. The structure in this state is further treated with chemicals 
which etch the metallic evaporated film 2, thereby to obtain a structure 
in a state shown in FIG. 1-C wherein only the metallic evaporated film in 
an area corresponding to the remaining part of the coating film 3 is left 
and wherein the metallic evaporated film in the other area is dissolved 
and removed. In this way, a glass plate in which the metallic evaporated 
film remains only in the area irradiated by the electron beam can be 
obtained. If, in the irradiation by the electron beam, a certain pattern 
is depicted on the polymer coating film with the electron beam, the 
metallic evaporated film will remain according to the depicted pattern on 
the glass substrate after the step of etching the metallic evaporated 
film. Using an electron-beam depicting equipment and the electron-beam 
resist in this manner, even a complicated and very fine pattern can be 
worked extremely precisely, and a metallic evaporated film of any desired 
design can be obtained. When a sample and a mask are held in close contact 
and they are irradiated by electromagnetic waves of short wavelengths, 
e.g. X-rays, a complicated and very fine pattern can be worked extremely 
precisely and a metallic evaporated film of any desired design can be 
obtained likewise to the above. 
It has been revealed, however, that when the polymeric material containing 
epoxy groups and bromine atoms that has been let to stand after the 
synthesis is applied in conformity with the steps of FIGS. 1-A to 1-C, a 
phenomenon in which the width of a line irradiated by an electron beam 
becomes somewhat greater can take place. It has also been revealed that 
the resist solution undergoes insolubilization little by little also when 
let to stand, that the viscosity and sensitivity of the resist solution 
rise with the insolubilization, and that when the insolubilization becomes 
more conspicuous, a phenomenon in which the entire solution solidifies can 
take place. 
That is, in case where, by way of example, a structure in the state of FIG. 
1-B is to be obtained by irradiating the desired part of the coating film 
3 in FIG. 1-A with the electron beam and thereafter conducting the 
developing treatment with the organic solvent, the sensitivity can become 
different depending on the date of irradiation, the degree of fog and, 
accordingly, the width of a line can become different depending on the 
developing period of time, or a fog film can appear in an unirradiated 
area. Such fogging phenomena give rise to the instability of the 
operations, and become a very serious problem in the technological field 
of semiconductor devices requiring precise working, especially in the 
field of integrated circuits (IC's), magnetic bubble domain memories, etc. 
requiring high working precisions in complicated microcircuits. A method 
for preventing such fogging phenomena must be taken by all means. 
The phenomenon in which the organic polymer coating film in the 
unirradiated area or the resist solution becomes insoluble, as described 
above, is usually called the "spontaneous insolubilization" or 
"instability". Although the mechanism by which the phenomenon is caused is 
not clear, the most important cause will be that the polymeric material 
being the resist material is dissolved little by little, induces cross 
linkage in any form and consequently affects the fog. 
SUMMARY OF THE INVENTION 
An object of this invention is to provide a radiation-sensitive composition 
free from the "instability". 
This and other objects of this invention is accomplished by a 
radiation-sensitive composition comprising a radiation-sensitive polymer 
which has a plurality of epoxy groups and a plurality of bromine atoms in 
one molecule, and at least one stabilizer which is selected from the group 
consisting of compounds having stable-free radicals, polymerization 
inhibitors, ketone-amine reaction products and phenol derivatives.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The inventors introduced a variety of additives as stabilizers into 
radiation-sensitive polymers. Then, it has been found out that compounds 
having stable free radicals, polymerization inhibitors, ketone-amine 
reaction products or phenol derivatives which have solubilities to organic 
substances exhibit particularly excellent "instability" preventing- or 
suppressing-effects. Accordingly, the radiation-sensitive composition of 
this invention is characterized in that the stabilizers are added to the 
polymeric material. Thus, the "instability" can be easily prevented 
without any degradation of the sensitivities of the polymeric material to 
radiations such as electron beams, ion beams, .gamma.-rays, neutron beams 
and X-rays, and extraordinarily stabilized resist materials can be 
obtained. 
The mechanism of the instability preventing-effect is not definite. 
However, since the instability preventing-effect is is attained by adding 
compounds having stable free radicals, polymerization inhibitors, 
ketone-amine reaction products or phenol derivatives as stabilizers, it is 
considered that the polymeric material being the resist material will be 
dissolved little by little to generate radicals and that the active 
radicals will cause the instability. It is considered that the active 
radicals will be inactivated by adding the additives as mentioned above, 
with the result that the cross linkage of the polymers will be impeded. 
As the compounds having stable free radicals, there are 
2,2-diphenyl-1-picrylhydrazyl; 
.alpha.,.gamma.-bisdiphenylene-.beta.-phenylallyl; etc. As the 
polymerization inhibitors, there are quinones of hydroquinone monomethyl 
ether; benzoquinone; methylquinone; 2,5-dimethylquinone; thymoquinone; 
trimethylquinone; tetramethylquinone; chloranil; 1,4-naphthoquinone; 
phenanthraquinone; chrysenequinone; 2-methoxyquinone; 
2-chlorobenzoquinone; dichlorobenzoquinone; methylnaphthoquinone; 
dichloronaphthoquinone; anthraquinone; 2-tert-butylanthraquinone; etc. As 
the ketone-amine reaction products, there are mentioned, for example, 
polymerization products of 2,2,4-trimethyl-1,2-dihydroquinoline, and 
quinoline derivatives of 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline; 
6-dodecyl-2,2,4-trimethyl-1,2-dihydroquinoline. As the phenol derivatives, 
there are mentioned, for example, 4,4'-dioxydiphenyl; dioxydiphenyl 
methane derivatives; and 1,1-bis-(4-hydroxyphenyl)-cyclohexane. 
As a method for adding the stabilizer to the polymer, i.e. high molecular 
weight compound, the stabilizer may be dissolved in an organic solvent 
before the high molecular compound is dissolved in the solvent. 
Alternatively, the stabilizer may be dissolved simultaneously with the 
high molecular compound or may be dissolved in a solution in which the 
high molecular compound is dissolved in advance. With all the methods, 
substantially equal effects are achieved. To be noted at the time of the 
addition is to sufficiently dissolve the additive so that it may not exist 
in the solution in the solid state. Even when the quantity of addition of 
the stabilizer is slight, the corresponding effect is noticed. In general, 
as the quantity of addition is larger, the effect is more remarkable. When 
the additive is added in large quantities, it is sometimes precipitated on 
a coating film. It is therefore necessary to confine the quantity of 
addition to the extent that no precipitation occurs. The precipitation of 
the additive on the coating film becomes a cause for generating pinholes 
in the coating film and lowers the accuracy of etching, so that it must be 
avoided. Regarding the quantity of the additive, accordingly, a preferable 
range is 0.01% to 5%, with respect to the quantity of the high molecular 
compound. 
The high molecular compound which is applied to this invention comprises at 
least one polymeric material selected from the group consisting of 
brominated and epoxidized polymers of butadiene, brominated and epoxidized 
copolymers of butadiene, brominated and epoxidized polymers of isoprene, 
brominated and epoxidized copolymers of isoprene, brominated products of 
copolymers of butadiene with addition-polymerizable compounds containing 
an epoxy group, brominated products of copolymers of isoprene with 
addition-polymerizable compounds containing an epoxy group and epoxidized 
products of copolymers of one of butadiene and isoprene with 
addition-polymerizable compounds containing a bromine atom. 
As the polymers of butadiene, there may be employed any of 
1,2-polybutadiene, 1,4-polybutadiene, polybutadienes having both the 1,2- 
and 1,4-structures and mixtures thereof. The same applies to the polymers 
of isoprene. As the copolymers of butadiene, there can be used known 
butadiene copolymers such as styrene-butadiene copolymers and 
butadiene-isoprene copolymers. Likewise, known isoprene copolymers can be 
used as the copolymers of isoprene. Further, as the epoxy 
group-containing, addition-polymerizable monomers, there are glycidyl 
acrylate, glycidyl methacrylate, etc. 
A preferred degree of epoxidation is about 10% to about 70%, and a 
preferred degree of bromination is about 7% to about 50%. The "degree of 
epoxidation or bromination" means the ratio of the epoxidized or 
brominated monomer units in the polymer or copolymer to the total monomer 
units. The calculation of the degree of epoxidation or bromination is made 
based on the supposition that one monomer unit is epoxidized by one atom 
of oxygen or that one monomer unit is brominated by two atoms of bromine. 
Since either reaction of epoxidation and bromination takes place on one 
monomer unit, the value of the sum of the degree of epoxidation and the 
degree of bromination is always lower than 100%. 
A preferable range of the molecular weight of the high molecular compound 
is about 500 to about 10,000,000. A more preferable range is about 100,000 
to 2,000,000. These values of the molecular weight are measurements by the 
viscosity process. 
As a liquid developer to be used when the radiation-sensitive composition 
of this invention is employed as an electron-beam resist, there can be 
used any solvent capable of dissolving the composition and incapable of 
dissolving a radiation-crosslinked product of the high molecular compound. 
Among such solvents, dioxane, butyl acetate or a mixed solvent containing 
dioxane or butyl acetate, for example, butyl acetate-ethyl cellosolve or 
dioxane-ethyl cellosolve is an excellent liquid developer. 
When the composition of this invention is employed as, e.g., an 
electron-beam resist in the fabrication of a photo-resist mask for 
manufacturing a semiconductor device, a mask of extraordinarily high 
working precision can be made. When the surface of a coating film of the 
composition of this invention is scanned by an electron beam directly 
without any mask, a resist film of desired shape having an extraordinarily 
high working precision can be formed, and this technique can be put into 
practical use instead of the conventional photolithography in the field of 
semiconductor technology. Further, the composition of this invention can 
be satisfactorily used as a recording material for the recording of a very 
fine pattern, the high-density picture recording, the electron-beam 
holography or the X-ray holography. 
Hereunder, this invention will be described more concretely with reference 
to examples. 
In all of the following examples, in order to know the extent of 
"instability", the electron-beam sensitivity after a solution of the 
radiation-sensitive composition has been let to stand for a certain time 
is indicated, or the solubility to a solvent after a coating film has been 
let to stand for a certain time is indicated. 
EXAMPLE 1 
To 50 ml of monochlorobenzene was added 1.5 g of 1,2-polybutadiene (RB 820 
manufactured by Japan Synthetic Rubber Co.; having a 1,2-structure content 
of about 82%, a 1,4-structure content of about 18% and a molecular weight 
of about 160,000), and the mixture was heated to form a homogeneous 
solution. At the room temperature, to the solution was added an acetic 
acid solution of peracetic acid in an amount sufficient to epoxidize all 
the double bonds of the 1,2-polybutadiene, and the mixture was agitated 
for 2 hours to effect epoxidation of the 1,2-polybutadiene. 
The acetic acid solution of peracetic acid used for the epoxidation was 
prepared in the following manner. 0.20 ml of concentrated sulfuric acid, 
22 ml of glacial acetic acid and 4.1 ml of 30% aqueous hydrogen peroxide 
were mixed together, and the mixture was let to stand still at the room 
temperature overnight. 3.0 g of sodium acetate trihydrate was added to and 
dissolved in the mixture. The resulting precipitate of sodium sulfate was 
removed to obtain an acetic acid solution of peracetic acid, which 
contained about 1.1 moles per liter of peracetic acid. 
While the reaction mixture under such state was agitated continuously, a 
solution of 2.3 g of potassium bromide (containing bromine in an amount 
sufficient to add to 35% of the original double bonds in the starting 
1,2-polybutadiene) in 7 ml of water was added to the reaction mixture. By 
reaction of potassium bromide with peracetic acid left in the reaction 
mixture, bromine was generated and the color of the reaction mixture 
became brown. However, by the reaction of addition to the double bonds of 
the 1,2-polybutadiene the bromine was gradually consumed and was 
completely consumed at last, and the reaction mixture became colorless. 
The reaction mixture was washed twice with about 200 ml of water and 2.0 g 
of sodium bicarbonate was added to the reaction mixture to neutralize 
remaining acetic acid and a minute amount of peracetic acid. Then, 25 ml 
of cyclohexane was added to the reaction mixture and the resulting mixture 
was subjected to centrifugal separation to recover a transparent 
supernatant. 50 ml of cyclohexane was added to the supernatant to 
precipitate the resulting polymeric compound. The polymeric compound was 
dissolved in 20 ml of monochlorobenzene to form a homogeneous solution. 
This solution is a monochlorobenzene solution of brominated epoxidized 
1,2-polybutadiene. The fact that 1,2-polybutadiene has been epoxidized and 
brominated according to the above method can be confirmed from the fact 
that an absorption peak at a wave number of 830 cm.sup.-1 inherent to the 
epoxy group and an absorption peak at a wave number of 600 cm.sup.-1 
inherent to the carbon-to-bromine bond appear in the infrared absorption 
spectrum of the product. The degree of epoxidation of the high molecular 
compound is about 18%, and the degree of bromination is about 35%. 
The monochlorobenzene solution of the brominated epoxidized 
1,2-polybutadiene was divided into two parts. 1 weight-% of 
2,2-diphenyl-1-picrylhydrazyl as based on the weight of the polymer was 
added as a stabilizer to one of the divided parts, to obtain a homogeneous 
mixed solution and the other part was retained with the addition of a 
stabilizer. After allowing the two types of solutions to stand at the room 
temperature for 50 days, the electron-beam sensitivity characteristics of 
these resist materials were measured as follows. Each solution was 
spin-coated and dried on an oxidized silicon wafer to form a polymer film 
having a thickness of 0.3 to 0.6 .mu.m. The coated wafer was placed in an 
electron beam exposure apparatus and was irradiated in vacuum with an 
electron beam having an acceleration voltage of 15 KV, while the dose was 
varied. Then, the coated wafer was taken out of the apparatus and dipped 
in a developer for 2 minutes to effect development, the developer 
consisting of n-butyl acetate and ethyl cellosolve at a volumetric ratio 
of 3:2. Thereafter, the developer was removed by hot air drying, and the 
thickness of the polymer film insolubilized by exposure to the electron 
beam and left on the surface of the silicon wafer was measured by an 
interference microscope. The thickness of the film left after the 
development was plotted with respect to the electron beam dose, to obtain 
a diagram representative of the electron-beam sensitivity characteristic. 
The electron-beam sensitivity characteristics thus obtained are shown as 
curves 21 and 22 in FIG. 2. The curve 21 is the sensitivity curve of the 
radiation-sensitive material having no stabilizer, while the curve 22 is 
the sensitivity curve of the radiation-sensitive composition containing 
the stabilizer. For reference, the electron-beam sensitivity 
characteristic of the brominated epoxidized 1,2-polybutadiene with no 
stabilizer added thereto as measured immediately after the synthesis is 
shown as a curve 23 in FIG. 2. 
As apparent from FIG. 2, the radiation-sensitive material with no 
stabilizer added thereto has the sensitivity made approximately three 
times higher at a crosslinked film thickness of 50% when allowed to stand 
at the room temperature for 50 days after the synthesis. It is also 
understood that, since the gradient of the sensitivity curve worsens, a 
low contrast characteristic is exhibited. 
On the other hand, the curves 22 and 23 agree perfectly, and the 
radiation-sensitive composition in which 1 weight-% of 
2,2-diphenyl-1-picrylhydrazyl, based on the polymer, is added as the 
stabilizer has no sensitivity change even when allowed to stand at the 
room temperature for 50 days. It is also appreciated that, since the 
gradient of the sensitivity curve does not change, a remarkable 
stabilizing effect is achieved. 
EXAMPLE 2 
A radiation-sensitive composition was prepared by using the same solution 
of brominated epoxidized 1,2-polybutadiene as in Example 1 and adding 0.1 
weight-% of 2,2-diphenyl-1-picrylhydrazyl as based on the quantity of 
polymer in solution. After allowing this composition to stand at the room 
temperature for 30 days, measurements were made by the same method as in 
Example 1. As the result, quite the same sensitivity curve as the curve 22 
in FIG. 2 was obtained. It is understood from this fact that the 
composition has a stabilizing effect due to the presence of the 
stabilizer. 
EXAMPLE 3 
A radiation-sensitive composition was prepared by using the same solution 
of brominated epoxidized 1,2-polybutadiene as in Example 1 and adding 0.01 
weight-% of 2,2-diphenyl-1-picrylhydrazyl as based on the quantity of the 
polymer. After letting this composition stand at the room temperature for 
50 days, measurements were made by the same method as in Example 1. As the 
result, a sensitivity characteristic as illustrated by curve 24 in FIG. 2 
was obtained. It is understood that the composition is effective insofar 
as it is used in a certain short period. 
EXAMPLE 4 
A radiation-sensitive composition was prepared by using the same solution 
of brominated epoxidized 1,2-polybutadiene as in Example 1 and adding 0.5 
weight-% of .alpha.,.gamma.-bisdiphenylene-.beta.-phenylallyl based on the 
quantity of the polymer in solution. After allowing this composition to 
stand at the room temperature for 50 days, measurements were made by the 
same method as in Example 1. As the result, quite the same sensitivity 
curve as the curve 22 in FIG. 2 was obtained. 
EXAMPLE 5 
A radiation-sensitive composition was prepared by using the brominated 
epoxidized 1,2-polybutadiene synthesized by the same method as in Example 
1 and adding 1 weight-% of hydroquinone monomethyl ether based on the 
quantity of the polymer in solution. After allowing this composition to 
stand at the room temperature for 30 days, it was applied on the surface 
of a chromium evaporated film on a glass substrate and then dried. Even 
when allowed to stand at the room temperature for 4 days, a coating film 
thus formed could be easily dissolved and removed by a liquid developer 
consisting of n-butyl acetate and ethyl cellosolve at a volumetric ratio 
of 1:1, and not any insolubilized part occurred. In contrast, a 
comparative example of the radiation-sensitive composition to which 
hydroquinone monomethyl ether was not added could not be perfectly 
dissolved and removed by the same developer, and it left an evident 
insolubilized film. 
Besides the foregoing examples, similar tests were conducted using 
benzoquinone, etc. as stabilizers. In all the cases, the stabilizing 
effect was noted. It has been revealed that, as described previously, any 
of compounds having stable radicals or quinones, which are dissolved in 
organic solvents, can be used as a stabilizer in this invention. 
EXAMPLE 6 
A radiation-sensitive composition was prepared by using the same solution 
brominated epoxidized 1,2-polybutadiene as prepared in Example 1 and 
adding 1 weight-% of a polymerization product of 
2,2,4-trimethyl-1,2-dihydroquinoline (Antigen RD manufactured by Sumitomo 
Chemicals Co.) based on the quantity of the polymer. After letting this 
composition stand at the room temperature for 30 days, measurements were 
made by the same method as in Example 1. As the result, quite the same 
sensitivity curve as the curve 22 in FIG. 2 was obtained. 
EXAMPLE 7 
A radiation-sensitive composition was prepared by using the same solution 
of brominated epoxidized 1,2-polybutadiene prepared as in Example 1 and 
adding 0.5 weight-% of 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline 
(Nokrak AW manufactured by Ouchi Shinko Co.) as based on the quantity of 
polymer. After letting this composition stand at the room temperature for 
35 days, measurements were made by the same method as in Example 1. As the 
result, quite the same sensitivity curve as the curve 22 in FIG. 2 was 
obtained. 
EXAMPLE 8 
A radiation-sensitive composition was prepared by using the same solution 
brominated epoxidized 1,2-polybutadiene as prepared in Example 1 and 
adding 0.3 weight-% of a low-temperature reaction product between diphenyl 
amine and acetone (Antigen AM manufactured by Sumitomo Chemicals Co.) as 
based on the quantity thereof. After letting this composition stand at the 
room temperature for 50 days, measurements were made by the same method as 
in Example 1. As the result, quite the same sensitivity curve as the curve 
22 in FIG. 2 was obtained. 
EXAMPLE 9 
A radiation-sensitive composition was prepared by using the same solution 
of brominated epoxidized 1,2-polybutadiene as prepared in Example 1 and 
0.5 weight-% of 1,1-bis-(4-hydroxyphenyl)-cyclohexane being a phenol 
derivative (Antigen W manufactured by Sumitomo Chemicals Co.) as based on 
the quantity of polymer. After letting this composition stand at the room 
temperature for 50 days, measurements were made by the same method as in 
Example 1. As the result, quite the same sensitivity curve as the curve 22 
in FIG. 2 was obtained. 
EXAMPLE 10 
In 50 ml of monochlorobenzene was dissolved 1.9 g of 1,4-polyisoprene 
(Cariflex IR 309 manufactured by Shell Chemical Corp.) to form a 
homogeneous solution. A solution of 3.3 g of potassium bromide (containing 
bromine in an amount sufficient to add to 50% of the double bonds of the 
1,4-polyisoprene) in 10 ml of water was added to the above solution. The 
mixture was agitated sufficiently. While agitation was being continued, 32 
ml of an acetic solution of peracetic acid prepared in the same manner as 
described in Example 1 was added to the mixture. The color of bromine 
formed by the reaction between peracetic and potassium bromide disappeared 
substantially instantaneously by addition of bromine to the double bonds 
of the 1,4-polyisoprene. After completion of the addition of peracetic 
acid, the reaction mixture was agitated for 2 hours to advance 
epoxidation. Subsequently, the reaction mixture was neutralized and 
refined by the same method as in Example 1. Finally, the polymer solution 
was dissolved in a mixed solution consisting of 20 ml of monochlorobenzene 
and 20 ml of toluene, to obtain a solution of brominated epoxidized 
1,4-polyisoprene. 
The electron-beam sensitivity characteristic of the brominated epoxidized 
1,4-polyisoprene thus obtained was measured in the same manner as in 
Example 1. As the result, a crosslinked film began to remain at 
2.5.times.10.sup.-8 C/cm.sup.2, and the thickness of the crosslinked film 
became equal to that of a coating film at 4.times.10.sup.-7 C/cm.sup.2. A 
radiation-sensitive composition was prepared by adding to the polymer 
solution, 1 weight-% of 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline 
(Nokrak AW manufactured by Ouchi Shinko Co.) as based on the quantity of 
the polymer. After letting this composition stand at the room temperature 
for 100 days, the electron-beam sensitivity of the composition was 
measured. As the result, quite the same values as measured immediately 
after the synthesis were exhibited, and it was known that no instability 
occurred. 
EXAMPLE 11 
An experiment similar to Example 7 was carried out in which the quantity of 
6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline was 5 weight-% on the basis 
of the polymer. In this case, the same result as in Example 7 was 
obtained. No pinhole appeared in the film. 
In the foregoing examples, brominated substances of epoxidized 
1,2-polybutadiene and epoxidized 1,4-polyisoprene have been exemplified as 
the radiation-sensitive materials. It has been revealed that similar 
effects are achieved on other materials made of brominated substances such 
as a copolymer of epoxidized isoprene, a copolymer between an 
addition-polymerizable compound having a glycidyl group and butadiene, and 
a copolymer between an addition-polymerizable compound having a glycidyl 
group and isoprene.