Disclosed are novel high-sensitivity positive- and negative-working chemical-sensitization photoresist compositions capable of giving a highly heat-resistant patterned resist layer of high resolution having excellently orthogonal cross sectional profile without being influenced by standing waves. The composition contains, as an acid generating agent by irradiation with actinic rays, a specific cyano-substituted oximesulfonate compound such as .alpha.-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide. The advantages obtained by the use of this specific acid-generating agent is remarkable when the film-forming resinous ingredient has such a molecular weight distribution that the ratio of the weight-average molecular weight to the number-average molecular weight does not exceed 3.5.

BACKGROUND OF THE INVENTION 
The present invention relates to a chemical-sensitization photoresist 
composition or, more particularly, to a photoresist composition, which may 
be of the positive-working type or negative-working type, containing a 
unique acid-generating agent capable of releasing an acid when exposed to 
actinic rays. The photoresist composition gives a patterned resist layer 
having high heat resistance and high resolution with a high 
photosensitivity of the photoresist composition without being affected by 
the influences of standing waves so that the patterned resist layer has an 
excellently orthogonal cross section. 
It is a trend in recent years in the manufacturing technology of various 
electronic devices such as semi-conductor devices involving the process of 
photolithographic patterning works that so-called chemical-sensitization 
photoresist compositions are acquiring more and more prevalence by 
replacing those of the traditional types by virtue of the high sensitivity 
and high resolving power as compared with conventional photoresist 
compositions. The chemical-sensitization photoresist composition mentioned 
above contains a radiation-sensitive acid-generating agent which is a 
compound capable of releasing an acid when exposed to actinic rays so as 
to catalyze the solubilizing reaction and crosslinking reaction of the 
resinous ingredient in the positive- and negative-working photoresist 
compositions, respectively. 
The chemical-sensitization photoresist compositions include two classes of 
positive-working and negative-working ones depending on the activity of 
the radiation-released acid either to increase or to decrease, 
respectively, the solubility of the film-forming resinous ingredient in 
the composition in an aqueous alkaline solution as a developer. In other 
words, the chemical-sensitization photoresist composition is 
positive-working when the film-forming resinous ingredient therein is 
imparted with an increase in the solubility in the alkaline developer 
solution and is negative-working when the film-forming resinous ingredient 
therein is imparted with a decrease in the solubility in the alkaline 
developer solution. 
Accordingly, a positive-working chemical-sensitization photoresist 
composition usually contains a polyhydroxystyrene and the like of which a 
part of the hydroxy groups are substituted by solubility-suppressing 
acid-dissociable protective groups such as tert-butoxycarbonyl and 
tetrahydropyranyl groups while the film-forming resinous ingredient in the 
negative-working chemical-sensitization photoresist composition is usually 
a combination of an acid-crosslinkable melamine resin, urea resin and the 
like with an alkali-soluble resin such as novolac resins and 
polyhydroxystyrene resins optionally protected for a part of the hydroxy 
groups with the solubility-suppressing groups. 
It is known that the resinous ingredient mentioned above in the photoresist 
composition should have a narrow molecular weight distribution expressed 
by the ratio of the weight-average molecular weight Mw to the 
number-average molecular weight Mn, i.e. Mw:Mn, in order to ensure high 
resolution of patterning and high heat resistance of the patterned resist 
layer. 
The acid-generating agent heretofore proposed or currently used in 
chemical-sensitization photoresist compositions includes oximesulfonate 
compounds as disclosed in Japanese Patent Kokai 1-124848, 2-154266, 
2-161444 and 6-67433, of which those oximesulfonate compounds having a 
cyano group in the molecule are preferred as exemplified by 
.alpha.-(p-toluenesulfonyloxyimino)benzyl cyanide, 
.alpha.-(4-chlorobenzenesulfonyloxyimino)benzyl cyanide, 
.alpha.-(4-nitrobenzenesulfonyloxyimino)benzyl cyanide, 
.alpha.-(4-nitro-2-trifluoromethylbenzenesulfonyloxyimino)benzyl cyanide, 
.alpha.-(benzenesulfonyloxyimino)-4-chlorobenzyl cyanide, 
.alpha.-(benzenesulfonyloxyimino)-2,4-dichlorobenzyl cyanide, 
.alpha.-(benzenesulfonyloxyimino)-2,6-dichlorobenzyl cyanide, 
.alpha.-(benzenesulfonyloxyimino)-4-methoxybenzyl cyanide, 
.alpha.-(2-chlorobenzenesulfonyloxyimino)-4-methoxybenzyl cyanide, 
benzenesulfonyloxyimino-2-thienyl acetonitrile, 
.alpha.-(4-dodecylbenzenesulfonyloxyimino)benzyl cyanide, 
.alpha.-(p-toluenesulfonyloxyimino)-4-methoxybenzyl cyanide, 
.alpha.-(4-dodecylbenzenesulfonyloxyimino)-4-methoxybenzyl cyanide, 
p-toluenesulfonyloxyimino-3-thienyl acetonitrile and the like. 
It is noted that each of the above named cyano group-containing 
oximesulfonate compounds has two aromatic groups in a molecule, one, 
substituting the .alpha.-carbon atom to which the cyano group --CN is 
bonded and, the other, forming the sulfonate ester. While the acid 
released from such a dually aromatic oximesulfonate compound by the 
irradiation with actinic rays is therefore an aromatic sulfonic acid such 
as benzenesulfonic acid and p-toluenesulfonic acid, a 
chemical-sensitization photoresist composition formulated with such an 
oximesulfonate compound and a resinous ingredient having a narrow 
molecular weight distribution mentioned above has a defect that the 
patterning of the resist layer is susceptible to the influences of 
standing waves so that the cross sectional profile of the patterned resist 
layer is not exactly orthogonal but has wavy or undulated side lines. 
SUMMARY OF THE INVENTION 
The present invention accordingly has an object to provide a novel and 
improved chemical-sensitization photoresist composition, which may be 
positive-working or negative-working, free from the above described 
problems and disadvantages in the prior art chemical-sensitization 
photoresist compositions by using, as the acid-generating agent, a unique 
cyano group-containing oximesulfonate compound, by virtue of which the 
photoresist composition has a very high sensitivity to actinic rays and is 
capable of forming a patterned resist layer having an excellently 
orthogonal cross sectional profile and high heat resistance as well as 
high resolution of the pattern without being influenced by the standing 
waves. 
Thus, the present invention provides, as the first aspect of the invention, 
a positive-working chemical-sensitization photoresist composition which 
comprises, in the form of a uniform solution in an organic solvent: 
(a1) 100 parts by weight of an alkali-soluble hydroxy group-containing 
resin such as a polyhydroxystyrene, of which at least a part of the 
hydroxy groups are substituted each by an acid-dissociable substituent 
group and the ratio of the weight-average molecular weight to the 
number-average molecular weight Mw:Mn does not exceed 3.5; and 
(b) from 0.1 to 30 parts by weight of a cyano group-containing 
oximesulfonate compound, as an acid-generating agent, represented by the 
general formula 
EQU R.sup.1 --C(CN).dbd.N--O--SO.sub.2 --R.sup.2, (I) 
in which R.sup.1 is a monovalent aromatic group and R.sup.2 is an alkyl 
group having 1 to 4 carbon atoms and unsubstituted or substituted by 
halogen atoms. 
The present invention further provides, as the second aspect of the 
invention, a negative-working chemical-sensitization photoresist 
composition which comprises, in the form of a uniform solution in an 
organic solvent: 
(a2) 100 parts by weight of an alkali-soluble resin such as a 
polyhydroxystyrene, copolymer of hydroxystyrene and styrene and novolac 
resin, of which the ratio of the weight-average molecular weight to the 
number-average molecular weight Mw:Mn does not exceed 3.5; 
(b) from 0.1 to 30 parts by weight of a cyano group-containing 
oximesulfonate compound, as an acid-generating agent, represented by the 
general formula 
EQU R.sup.1 --C(CN).dbd.N--O--SO.sub.2 --R.sup.2, (I) 
in which R.sup.1 is a monovalent aromatic group and R.sup.2 is an alkyl 
group having 1 to 4 carbon atoms and unsubstituted or substituted by 
halogen atoms; and 
(c) from 3 to 70 parts by weight of an acid-crosslinkable resin such as 
melamine resins, urea resins and guanamine resins. 
Some of the cyano group-containing oximesulfonyl compounds represented by 
the general formula (I) are novel and not known in the prior art. Novel 
species of the cyano group-containing oximesulfonyl compounds can be 
represented by the general formula 
##STR1## 
in which R.sup.2 has the same meaning as defined above and each of 
R.sup.3, R.sup.4 and R.sup.5 is, independently from the others, an atom or 
group selected from the group consisting of a hydrogen atom, alkyl groups 
having 1 to 4 carbon atoms, alkoxy group having 1 to 4 carbon atoms and 
atoms of halogen, e.g., fluorine, chlorine and bromine, with the proviso 
that at least one of R.sup.3, R.sup.4 and R.sup.5 in a molecule is an 
alkyl group, alkoxy group or halogen atom. 
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
As is described above, both of the positive-working and negative-working 
photoresist compositions provided by the present invention are 
characterized by the use of a specific cyano group-containing 
oximesulfonate compound of the general formula (I) which has, different 
from conventional dually aromatic cyano group-containing oximesulfonate 
compounds mentioned above, only one aromatic group bonded to the same 
carbon atom as that to which the cyano group --CN is bonded. It is a quite 
unexpected discovery that replacement of the conventional dually aromatic 
cyano group-containing oximesulfonate compound with the above defined 
specific oximesulfonate compound has an effect to overcome the problems 
and disadvantages in the chemical-sensitization photoresist compositions 
in the prior art. The improvement accomplished by the present invention is 
particularly remarkable when the film-forming resinous ingredient, i.e. 
component (a1) or (a2), has a narrow molecular weight distribution as 
defined by the ratio of the weight-average molecular weight Mw to the 
number-average molecular weight Mn not exceeding 3.5. 
The film-forming resinous ingredient as the component (a1) in the 
positive-working chemical-sensitization photoresist composition is an 
alkali-soluble resin having hydroxy groups, a part of which are 
substituted each by an acid-dissociable substituent group. The 
alkali-soluble resin suitable as the base material of the component (a1) 
includes homopolymers of hydroxystyrene, copolymers of hydroxystyrene and 
styrene or a styrene derivative, of which the molar fraction of the 
hydroxystyrene moiety is at least 70%, and copolymers of hydroxystyrene 
and (meth)acrylic acid or a derivative thereof as well as copolymers of 
(meth)acrylic acid and a derivative thereof, of which a part of the 
carboxylic hydroxy groups are substituted by the acid-dissociable groups. 
Among the above named hydroxy group-containing resins, homopolymers of 
hydroxystyrene and copolymers of styrene and hydroxystyrene are preferred. 
The above mentioned styrene derivative to be copolymerized with 
hydroxystyrene includes .alpha.-methylstyrene, 4-methylstyrene, 
2-methylstyrene, 4-methoxystyrene, 4-chlorostyrene and the like. The 
(meth)acrylic acid derivative mentioned above includes esters such as 
methyl (meth)acrylate, ethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate 
and 2-hydroxypropyl (meth)acrylate, (meth)acrylamide, (meth)acrylonitrile 
and the like. 
The acid-dissociable group substituting a part of the hydroxy groups in the 
above named hydroxy-containing resins to form the component (a1) in the 
inventive positive-working photoresist composition is selected from the 
group consisting of tert-alkyloxycarbonyl groups such as 
tert-butoxycarbonyl and tert-amyloxycarbonyl groups, 
tert-alkyloxycarbonylalkyl groups such as tert-butoxycarbonylmethyl group, 
tert-alkyl groups such as tert-butyl group, alkoxyalkyl groups such as 
ethoxyethyl and methoxypropyl groups, cyclic acetal groups such as 
tetrahydropyranyl and tetrahydrofuranyl groups, benzyl group and 
trimethylsilyl group, though not particularly limitative thereto. 
The degree of substitution by the above mentioned acid-dissociable groups 
for the hydroxy groups in the hydroxy-containing alkali-soluble resin is 
preferably in the range from 1 to 60% by moles or, more preferably, in the 
range from 10 to 50% by moles. 
In the formulation of the positive-working chemical-sensitization 
photoresist composition of the present invention, the component (a1) is 
preferably a polyhydroxystyrene resin of which a part of the hydroxy 
groups are protected by the substitution of tert-butoxycarbonyl groups, 
tetrahydropyranyl group, alkoxyalkyl groups, e.g., ethoxyethyl and 
methoxypropyl groups, or a combination thereof. 
The component (a2) in the negative-working chemical-sensitization 
photoresist composition of the invention is an alkali-soluble resin 
selected from the group consisting of novolac resins as a condensation 
product of a phenolic compound such as phenol, m- and p-cresols, xylenols, 
trimethyl phenols and the like and an aldehyde compound such as 
formaldehyde and the like in the presence of an acidic catalyst, 
hydroxystyrene-based polymers such as homopolymers of hydroxystyrene, 
partially or completely hydrogenated polyhydroxystyrenes, copolymers of 
hydroxystyrene with styrene or a derivative thereof and copolymers of 
hydroxystyrene and (meth)acrylic acid or a derivative thereof and 
(meth)acrylic resins such as copolymers of (meth)acrylic acid and a 
derivative thereof. The polyhydroxystyrene can optionally be substituted 
by the above mentioned acid-dissociable substituents for a part of the 
hydroxy groups. The above mentioned styrene derivative and (meth)acrylic 
acid derivatives can be exemplified by the same monomeric compounds as 
given above for the component (a1). 
Polyhydroxystyrene resins of a narrow molecular weight distribution having 
the value of Mw:Mn not exceeding 3.5 or, in particular, about 2.0 are 
available on the market as a "monodisperse" resin and can be used as such 
as the base material of the component (a1) or as the component (a2). No 
commercial products are available, on the other hand, for the novolac 
resin to be used as the component (a2) having the Mw:Mn value of 3.5 or 
smaller so that a conventional novolac resin of broader molecular weight 
distribution is subjected to a treatment of fractional precipitation to 
selectively remove the low molecular-weight fractions to such an extent 
that the fractionated polymer may have a Mw:Mn value not exceeding 3.5. 
The alkali-soluble resin as the component (a2) is selected preferably from 
the group consisting of cresol novolac resins, polyhydroxystyrene resins 
and copolymers of hydroxystyrene and styrene as well as polyhydroxystyrene 
resins of which a part of the hydroxy groups are substituted by 
tert-butoxycarbonyl groups. These alkali-soluble resins can be used either 
singly or as a combination of two kinds or more according to need. 
As is described before, the resin as the component (a1) or (a2) is required 
to have a narrow molecular weight distribution with a Mw:Mn value as small 
as possible or not exceeding 3.5 in order to ensure high heat resistance 
of the patterned resist layer and high pattern resolution with the 
photoresist composition. The Mw:Mn value should be preferably 2.5 or 
smaller or, more preferably, 1.5 or smaller for the polyhydroxystyrene 
resins and should be preferably 3.0 or smaller for the novolac resins in 
view of the difference in the molecular weight distribution between 
different types of resins as a consequence of the quite different 
molecular structures. The weight-average and number-average molecular 
weights of the resins can be determined by the gel permeation 
chromatographic (GPC) method by making reference to polystyrene samples 
having known molecular weights. 
The component (b) as an essential ingredient in both of the 
positive-working and negative-working chemical-sensitization photoresist 
compositions of the present invention is an acid generating agent which is 
a specific cyano group-containing oximesulfonate compound represented by 
the above given general formula (I). In the formula, R.sup.1 is a 
monovalent aromatic group such as phenyl, naphthyl, furyl and thienyl 
groups, optionally, substituted on the aromatic nucleus by one or more of 
substituents such as halogen, e,g., chlorine, bromine and iodine, atoms, 
alkyl groups having 1 to 4 carbon atoms, alkoxy groups having 1 to 4 
carbon atoms and nitro groups. The group denoted by R.sup.2 is a lower 
alkyl group having 1 to 4 carbon atoms, which can be a normal or branched 
alkyl group, including methyl, ethyl, n-propyl, isopropyl, n-butyl, 
isobutyl, sec-butyl and tert-butyl groups as well as a halogen-substituted 
lower alkyl group having 1 to 4 carbon atoms such as chloromethyl, 
trichloromethyl, trifluoromethyl and 2-bromopropyl groups. 
While, as is mentioned before, the conventional dually aromatic cyano 
group-containing oximesulfonate compound releases an aromatic sulfonic 
acid by the irradiation with actinic rays, the acid released from the 
oximesulfonate compound of the general formula (I) by the irradiation with 
actinic rays is a lower alkyl sulfonic acid or a halogenated lower alkyl 
sulfonic acid. It is the advantage of the present invention that the 
chemical-sensitization photoresist composition comprising this acid 
generating agent in combination with the component (a1) or with the 
components (a2) and (c) is capable of giving a patterned resist layer 
having excellent heat resistance, pattern resolution and sensitivity to 
actinic rays with an excellently orthogonal cross sectional profile of the 
patterned resist layer. 
Though not fully clear, the mechanism leading to the above mentioned 
unexpected improvement accomplished by the invention is presumably that, 
in contrast to the aromatic sulfonic acid generated in a conventional 
photoresist composition, which is poorly susceptible to thermal diffusion 
in the post-exposure baking treatment of the resist layer resulting in a 
wavy form of the cross sectional profile of the patterned resist layer due 
to the relatively large molecular dimension, in particular, in the 
resinous layer consisting of a polymeric resin of a narrow molecular 
weight distribution, the (halogenated) lower alkyl sulfonic acid having a 
smaller molecular dimension generated in the inventive photoresist 
composition is more diffusible in the resinous layer in the course of the 
post-exposure baking treatment to accomplish an excellent cross sectional 
profile of the patterned resist layer. 
Examples of the cyano group-containing oximesulfonate compound of the 
general formula (I) include: 
.alpha.-(methylsulfonyloxyimino)benzyl cyanide; 
.alpha.-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide; 
.alpha.-(trifluoromethylsulfonyloxyimino)benzyl cyanide; 
.alpha.-(trifluoromethylsulfonyloxyimino)-4-methoxybenzyl cyanide; 
.alpha.-(ethylsulfonyloxyimino)-4-methoxybenzyl cyanide; 
.alpha.-(propylsulfonyloxyimino)-4-methylbenzyl cyanide; 
.alpha.-(isopropylsulfonyloxyimino)-4-methoxybenzyl cyanide; 
.alpha.-(butylsulfonyloxyimino)-4-methoxybenzyl cyanide; 
.alpha.-(methylsulfonyloxyimino)-4-bromobenzyl cyanide; 
and the like. Among the above named compounds, the first mentioned 
.alpha.-(methylsulfonyloxyimino)benzyl cyanide is a known compound 
disclosed in U.S. Pat. No. 4,451,286 but the other compounds are each a 
novel compound not known in the prior art nor described in any 
literatures. 
As to the synthetic method for the preparation of the cyano 
group-containing oximesulfonate compounds of the general formula (I), a 
method similar to the method for the preparation of the dually aromatic 
cyano group-containing oximesulfonate compounds, as disclosed in Japanese 
Patent Kokai 1-124848, 2-154266 and 6-67433, is applicable here, though 
not particularly limitative thereto. Namely, the compound can be obtained 
by the esterification reaction between an oxime group-containing compound 
and sulfonic acid chloride in an organic solvent such as tetrahydrofuran, 
N,N-dimethyl formamide, N,N-dimethyl acetamide, N-methyl pyrrolidone and 
the like in the presence of a basic catalyst or an acid acceptor such as 
pyridine, triethylamine and the like. The oxime group-containing compound 
as one of the starting reactants in the above mentioned esterification 
reaction can be prepared by a known method described in The Systematic 
Identification of Organic Compounds, page 181 (1980, John Wiley & Sons), 
Die Makromolekulare Chemie, volume 108, page 170 (1967), Organic 
Syntheses, volume 59, page 95 (1979) and elsewhere. 
In the formulation of the inventive chemical-sensitization photoresist 
composition, the above named oximesulfonate compounds can be used either 
singly or as a combination of two kinds or more according to need. 
Although the preferable combination of two kinds or more of the 
oximesulfonate compounds depends on various factors such as the thickness 
of the resist layer, conditions of the post-exposure baking treatment, 
intervention of an anti-reflection coating layer between the substrate 
surface and the resist layer and so on, it is particularly preferable in 
the negative-working chemical-sensitization photoresist compositions of 
the invention, in particular, to use a combination of 
.alpha.-(methylsulfonyloxyimino)benzyl cyanide and 
.alpha.-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide in a weight ratio 
of 1:2 to 2:1. 
In the positive-working photoresist composition of the invention comprising 
the resinous ingredient as the component (a1) and the acid-generating 
agent as the component (b), an acid is generated from the component (b) in 
the areas of the photoresist layer irradiated with actinic rays so that 
the acid-dissociable substituent groups in the component (a1) are 
dissociated to regenerate the hydroxy groups in the resin molecules 
resulting in an increase in the alkali-solubility of the component (a1) in 
the development treatment to selectively remove the resist layer in the 
exposed areas giving a positively patterned resist layer. 
In the negative-working photoresist composition of the invention comprising 
the alkali-soluble resinous ingredient as the component (a2), the 
acid-generating agent as the component (b) and the acid-crosslinkable 
resinous ingredient as the component (c), an acid is also generated from 
the component (b) in the areas of the photoresist layer irradiated with 
actinic rays so that the acid-crosslinkable resinous ingredient serves for 
crosslinking of the component (a2) to decrease the alkali-solubility of 
the resist layer in the aqueous alkaline developer solution resulting in 
selective removal of the resist layer in the unexposed areas to give a 
negatively patterned resist layer. 
The acid-crosslinkable resinous ingredient as the component (c), which 
serves as a crosslinking agent for the component (a2), in the 
negative-working photoresist composition of the invention, is not 
particularly limitative and can be freely selected from those used in 
conventional negative-working chemical-sensitization photoresist 
compositions. Examples of the acid-crosslinkable resinous material as the 
component (c) include amino resins such as melamine resins, urea resins, 
guanamine resins, glycoluryl-formaldehyde resins, 
succinylamide-formaldehyde resins, ethyleneurea-formaldehyde resins and 
the like having hydroxy or alkoxy groups. These resinous compounds can be 
readily obtained by the reaction of melamine, urea, guanamine, glycoluryl, 
succinylamide or ethyleneurea with formaldehyde in boiling water to effect 
methylolation or further by the alkoxylation reaction of the methylolated 
resin with a lower alcohol. Melamine resins and urea resins are preferred 
either alone or as a combination. Commercial products of such resins are 
available on the market including, for example, those sold under the trade 
names of Nikalacs Mx-750 and Mw-30 as examples of melamine resins and 
Mx-290 as an example of urea resins (each a product by Sanwa Chemical 
Co.). These resinous compounds as the component (c) can be used either 
singly or as a combination of two kinds or more according to need. 
Besides the above named resinous compounds preferred as the component (c), 
certain benzene compounds having alkoxy groups such as 
1,3,5-tris(methoxymethoxy)benzene, 1,2,4-tris(isopropoxymethoxy) benzene, 
1,4-bis(sec-butoxymethoxy)benzene and the like and certain phenolic 
compounds having alkoxy groups and hydroxy groups such as 
2,6-di(hydroxymethyl)-p-cresol, 2,6-di(hydroxymethyl)-p-tert-butyl phenol 
and the like can be used as the component (c). 
It is important that the above described essential ingredients, i.e. 
components (a1) and (b) or components (a2), (b) and (c), are contained in 
specified weight proportions in each of the inventive positive-working and 
negative-working photoresist compositions. Namely, the amount of the 
component (b) is in the range from 0.1 to 30 parts by weight or, 
preferably, from 1 to 20 parts by weight per 100 parts by weight of the 
component (a1) or (a2), respectively, in respect of obtaining good balance 
of the pattern-forming behavior, uniformity of the resist layer and 
developability. When the amount of the component (b) is too small relative 
to the component (a1) or (a2), no complete patterning of the resist layer 
can be accomplished with the composition while, when the amount thereof is 
too large, a decrease is caused in the uniformity of the resist layer 
formed on the substrate surface along with a decrease in the 
developability of the resist layer not to give an excellently patterned 
resist layer. 
The amount of the component (c) compounded in the negative-working 
photoresist composition of the invention is in the range from 3 to 70 
parts by weight or, preferably, from 10 to 50 parts by weight per 100 
parts by weight of the component (a2) in respect of obtaining good balance 
in the properties of photosensitivity, uniformity of the resist layer and 
developability. When the amount of the component (c) is too small relative 
to the component (a2), the photoresist composition cannot be imparted with 
high photosensitivity to actinic rays while, when the amount thereof is 
too large, a decrease is caused in the uniformity of the resist layer 
formed on the substrate surface and in the developability. 
It is usual that the chemical-sensitization photoresist composition is used 
in the form of a uniform solution prepared by dissolving the above 
described essential ingredients and optional additives in an organic 
solvent. Examples of suitable organic solvents include ketone compounds 
such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl 
ketone, 2-heptanone and the like, polyhydric alcohols and derivatives 
thereof such as ethyleneglycol, ethyleneglycol monoacetate, 
diethyleneglycol, diethyleneglycol monoacetate, propyleneglycol, 
propyleneglycol monoacetate, dipropyleneglycol and dipropyleneglycol 
monoacetate as well as monomethyl, monoethyl, monopropyl, monobutyl and 
monophenyl ethers of the above named glycols and glycol monoacetates and 
the like, cyclic ether compounds such as dioxane and the like and ester 
compounds such as methyl lactate, ethyl lactate, methyl acetate, ethyl 
acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl 
methoxypropionate, ethyl ethoxypropionate and the like. These organic 
solvents can be used either singly or as a mixture of two kinds or more 
according to need. 
It is of course optional that the photoresist composition of the invention 
is admixed according to need with various kinds of optional additives 
having compatibility with the essential ingredients and conventionally 
used in photoresist compositions including, for example, auxiliary resins 
to improve the film properties of the resist layer, plasticizers, 
stabilizers, coloring agents, surface active agents and so on. 
The photolithographic procedure the patterning of a resist layer on a 
substrate surface using the inventive photoresist composition can be 
conventional as in the prior art. Namely, the surface of a substrate such 
as a semiconductor silicon wafer is uniformly coated with the photoresist 
composition in the form of a solution on a suitable coating machine such 
as spinners followed by drying of the coating layer to form a photoresist 
layer which is patternwise exposed through a pattern-bearing photomask to 
actinic rays such as ultraviolet light, deep ultraviolet light, excimer 
laser beams and the like or irradiated with electron beams by patternwise 
scanning to form a latent image of the pattern. After a post-exposure 
baking treatment of the resist layer, the latent image is subjected to a 
development treatment by using an aqueous alkaline solution of, for 
example, tetramethylammonium hydroxide in a concentration of 1 to 10% by 
weight as a developer followed by rinse with water and drying to give a 
resist layer patterned with high fidelity to the photomask pattern.

In the following, the positive-working and negative-working 
chemical-sensitization photoresist compositions of the invention are 
described in more detail by way of examples as preceded by the description 
of Synthesis Examples for the preparation of several compounds used as the 
component (b) in the Examples. In the following description, the term of 
"parts" always refers to "parts by weight". 
SYNTHESIS EXAMPLE 1 
.alpha.-(Methylsulfonyloxyimino)-4-methoxybenzyl cyanide was prepared in 
the following manner. Thus, 51.0 g (0.29 mole) of 
.alpha.-hydroxyimino-4-methoxybenzyl cyanide and a solution prepared by 
dissolving 44.0 g (0.43 mole) of triethylamine in 400 ml of 
tetrahydrofuran were introduced into a reaction vessel to form a uniform 
solution which was chilled to and kept at -5.degree. C. Into the solution 
in the reaction vessel were added dropwise 36.5 g (0.32 mole) of mesyl 
chloride over a period of 2 hours under agitation. The reaction mixture in 
the vessel was agitated at -5.degree. C. for 3 hours and then at about 
10.degree. C. for additional 2 hours. The reaction mixture was freed from 
tetrahydrofuran as the solvent by distillation under reduced pressure at 
30.degree. C. to give 73.6 g of a solid residue as a crude product which 
was purified by repeating recrystallization from acetonitrile to give 47.5 
g of a white crystalline product having a melting point of 116.degree. C., 
which could be identified to be the target compound from the results of 
the analysis described below. The above mentioned yield of the product 
corresponds to 64.5% of the theoretical value. 
The infrared absorption spectrum of the above obtained product compound had 
peaks at wave numbers of 1187 cm.sup.-1, 1265 cm.sup.-1, 1378 cm.sup.-1, 
1606 cm.sup.-1 and 2238 cm.sup.-1. The proton nuclear magnetic resonance 
(.sup.1 H-NMR) spectrum of the compound in acetone-d.sub.6 had peaks at 
.delta.=3.48 ppm, 3.93 ppm, 7.12 ppm and 7.90 ppm. The ultraviolet 
absorption spectrum of the compound in propyleneglycol monomethyl ether as 
the solvent had absorption bands at .lambda..sub.max =233 nm and 324 nm 
with a molar absorption coefficient of .epsilon.=8100 and 13800, 
respectively. 
SYNTHESIS EXAMPLE 2 
.alpha.-(Ethylsulfonyloxyimino)-4-methoxybenzyl cyanide was prepared in 
substantially the same manner as in Synthesis 
EXAMPLE 1 described above excepting replacement of 36.5 g (0.32 mole) of 
mesyl chloride with 40.1 g (0.32 mole) of ethanesulfonyl chloride. The 
yield of the crude solid product was 75.0 g, from which 62.1 g of a white 
crystalline product having a melting point of 102.degree. C. were obtained 
by repeating recrystallization from acetonitrile, which could be 
identified to be the target compound from the results of the analysis 
described below. The above mentioned yield of the product corresponds to 
80.6% of the theoretical value. 
The infrared absorption spectrum of the above obtained product compound had 
peaks at wave numbers of 1178 cm.sup.-1, 1267 cm.sup.-1, 1375 cm.sup.-1, 
1606 cm.sup.-1 and 2238 cm.sup.-1. The .sup.1 H-NMR spectrum of the 
compound in acetone-d.sub.6 had peaks at .delta.=1.47 ppm, 3.68 ppm, 3.93 
ppm, 7.12 ppm and 7.89 ppm. The ultraviolet absorption spectrum of the 
compound in propyleneglycol monomethyl ether as the solvent had absorption 
bands at .lambda..sub.max =233 nm and 325 nm with a molar absorption 
coefficient of .epsilon.=7400 and 12500, respectively. 
SYNTHESIS EXAMPLE 3 
.alpha.-(n-Butylsulfonyloxyimino)-4-methoxybenzyl cyanide was prepared in 
substantially the same manner as in Synthesis Example 1 described above 
excepting replacement of 36.5 g (0.32 mole) of mesyl chloride with 50.0 g 
(0.32 mole) of 1-butanesulfonyl chloride. The yield of the crude solid 
product was 90.0 g, from which 52.3 g of a white crystalline product 
having a melting point of 71.degree. C. were obtained by repeating 
recrystallization from acetonitrile, which could be identified to be the 
target compound from the results of the analysis described below. The 
above mentioned yield of the product corresponds to 55.3% of the 
theoretical value. 
The infrared absorption spectrum of the above obtained product compound had 
peaks at wave numbers of 1186 cm.sup.-1, 1268 cm.sup.-1, 1369 cm.sup.-1, 
1606 cm.sup.-1 and 2238 cm.sup.-1. The .sup.1 H-NMR spectrum of the 
compound in acetone-d.sub.6 had peaks at .delta.=0.96 ppm, 1.52 ppm, 1.89 
ppm, 3.65 ppm, 3.95 ppm, 7.14 ppm and 7.89 ppm. The ultraviolet absorption 
spectrum of the compound in propyleneglycol monomethyl ether as the 
solvent had absorption bands at .lambda..sub.max =233 nm and 325 nm with a 
molar absorption coefficient of .epsilon.=8000 and 13600, respectively. 
SYNTHESIS EXAMPLE 4 
.alpha.-(Isopropylsulfonyloxyimino)-4-methoxybenzyl cyanide was prepared in 
substantially the same manner as in Synthesis Example 1 described above 
excepting replacement of 36.5 g (0.32 mole) of mesyl chloride with 45.5 g 
(0.32 mole) of 2-propanesulfonyl chloride. The yield of the crude solid 
product was 88.0 g, from which 55.2 g of a white crystalline product 
having a melting point of 72.degree. C. were obtained by repeating 
recrystallization from acetonitrile, which could be identified to be the 
target compound from the results of the analysis described below. The 
above mentioned yield of the product corresponds to 61.2% of the 
theoretical value. 
The infrared absorption spectrum of the above obtained product compound had 
peaks at wave numbers of 1186 cm.sup.-1, 1267 cm.sup.-1, 1368 cm.sup.-1, 
1606 cm.sup.-1 and 2238 cm.sup.-1. The .sup.1 H-NMR spectrum of the 
compound in acetone-d.sub.6 had peaks at .delta.=1.52 ppm, 3.93 ppm, 3.95 
ppm, 7.13 ppm and 7.87 ppm. The ultraviolet absorption spectrum of the 
compound in propyleneglycol monomethyl ether as the solvent had absorption 
bands at .lambda..sub.max =233 nm and 324 nm with a molar absorption 
coefficient of .epsilon.=6800 and 11000, respectively. 
SYNTHESIS EXAMPLE 5 
.alpha.-(Methylsulfonyloxyimino)benzyl cyanide was prepared in the 
following manner. Thus, 52.5 g (0.36 mole) of .alpha.-hydroxyiminobenzyl 
cyanide and a solution prepared by dissolving 44.0 g (0.43 mole) of 
triethylamine in 400 ml of tetrahydrofuran were introduced into a reaction 
vessel to form a uniform solution which was chilled to and kept at 
-5.degree. C. Into the solution in the reaction vessel were added dropwise 
49.0 g (0.43 mole) of mesyl chloride over a period of 2 hours under 
agitation. The reaction mixture in the vessel was agitated at -5.degree. 
C. for 3 hours and then at about 10.degree. C. for additional 2 hours. The 
reaction mixture was freed from tetrahydrofuran as the solvent by 
distillation under reduced pressure at 30.degree. C. to give 75.0 g of a 
solid residue which was purified by repeating recrystallization from 
acetonitrile to give 64.5 g of a white crystalline product having a 
melting point of 120.degree. C., which could be identified to be the 
target compound from the results of the analysis described below and 
coincidence of the melting point with the known value reported in 
literatures. The above mentioned yield of the product corresponds to 80.0% 
of the theoretical value. 
The infrared absorption spectrum of the above obtained product compound had 
peaks at wave numbers of 844 cm.sup.-1, 902 cm.sup.-1, 1191 cm.sup.-1, 
1386 cm.sup.-1 and 2240 cm.sup.-1. The .sup.1 H-NMR spectrum of the 
compound in acetone-d.sub.6 had peaks at .delta.=3.50 ppm, 7.62 ppm, 7.68 
ppm and 7.97 ppm. The ultraviolet absorption spectrum of the compound in 
propyleneglycol monomethyl ether as the solvent had absorption bands at 
.lambda..sub.max =222 nm and 281 nm with a molar absorption coefficient of 
.epsilon.=8780 and 10800, respectively. 
SYNTHESIS EXAMPLE 6 
.alpha.-(Methylsulfonyloxyimino)-4-bromobenzyl cyanide was prepared in the 
following manner. Thus, 81.0 g (0.36 mole) of 
.alpha.-hydroxyimino-4-bromobenzyl cyanide and a solution prepared by 
dissolving 44.0 g (0.43 mole) of triethylamine in 400 ml of 
tetrahydrofuran were introduced into a reaction vessel to form a uniform 
solution which was chilled to and kept at -5.degree. C. Into the solution 
in the reaction vessel were added dropwise 49.0 g (0.43 mole) of mesyl 
chloride over a period of 2 hours under agitation. The reaction mixture in 
the vessel was agitated at -5.degree. C. for 3 hours and then at about 
10.degree. C. for additional 2 hours. The reaction mixture was freed from 
tetrahydrofuran as the solvent by distillation under reduced pressure at 
30.degree. C. to give 103.0 g of a solid residue which was purified by 
repeating recrystallization from acetonitrile to give 81.8 g of a white 
crystalline product having a melting point of 128.degree. C. which could 
be identified to be the target compound from the results of the analysis 
described below. The above mentioned yield of the product corresponds to 
75.0% of the theoretical value. 
The infrared absorption spectrum of the above obtained product compound had 
peaks at wave numbers of 844 cm.sup.-1, 902 cm.sup.-1, 1191 cm.sup.-1, 
1380 cm.sup.-1 and 2238 cm.sup.-1. The .sup.1 H-NMR spectrum of the 
compound in acetone-d.sub.6 had peaks at .delta.=3.50 ppm, 7.80 ppm and 
7.88 ppm. The ultraviolet absorption spectrum of the compound in 
propyleneglycol monomethyl ether as the solvent had absorption bands at 
.lambda..sub.max =226 nm and 292 nm with a molar absorption coefficient of 
.epsilon.=9270 and 13500, respectively. 
EXAMPLE 1 
A positive-working chemical-sensitization photoresist composition in the 
form of a uniform solution was prepared by dissolving, in 400 parts of 
propyleneglycol monomethyl ether acetate, 30 parts of a first 
polyhydroxystyrene having a weight-average molecular weight of 8000, of 
which the Mw:Mn value representing the molecular weight distribution was 
1.5 and 39% of the hydroxy groups were substituted by 
tert-butyloxycarbonyloxy groups, 70 parts of a second polyhydroxystyrene 
having a weight-average molecular weight of 8000, of which the Mw:Mn value 
representing the molecular weight distribution was 1.5 and 39% of the 
hydroxy groups were substituted by ethoxyethoxy groups, 2 parts of 
.alpha.-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide, 0.3 part of 
triethylamine, 0.2 part of salicylic acid and 5 parts of N,N-dimethyl 
acetamide followed by filtration of the solution through a membrane filter 
of 0.2 .mu.m pore diameter. 
A silicon wafer was uniformly coated with the thus prepared photoresist 
solution on a spinner followed by drying at 80.degree. C. for 90 seconds 
to give a dried photoresist layer having a thickness of 0.7 .mu.m. The 
resist layer was exposed to KrF excimer laser beams on a minifying 
projection exposure machine (Model NSR-2005EX8A, manufactured by Nikon 
Co.) in varied doses increased stepwise by an increment of 1 mJ/cm.sup.2 
followed by a post-exposure baking treatment at 110.degree. C. for 90 
seconds and then subjected to a development treatment in a 2.38% by weight 
aqueous solution of tetramethylammonium hydroxide at 23.degree. C. for 65 
seconds followed by rinse for 30 seconds with water and drying. The 
photosensitivity of the composition represented by the minimum exposure 
dose, at which the resist layer on the exposed areas could be completely 
removed by the above described development treatment, was 5 mJ/cm.sup.2. 
Further, a resist layer patterned in a line-and-space pattern of 0.22 .mu.m 
line width formed in the same manner as above was examined with a scanning 
electron microscope for the cross sectional profile of the line pattern to 
find that the cross section was excellently orthogonal and standing 
upright on the substrate surface without waviness. 
The heat resistance of the patterned resist layer was estimated by heating 
the line-patterned resist layer of 100 .mu.m line width at varied 
temperatures for 5 minutes followed by the microscopic examination to 
detect no collapsing or deformation along the shoulders of the 
line-patterned resist layer when the heating temperature was 120.degree. 
C. or lower. 
Comparative Example 1 
The formulation of the positive-working chemical-sensitization photoresist 
composition and the evaluation procedures of the same were substantially 
the same as in Example 1 excepting for the replacement of the first 
polyhydroxystyrene with the same amount of a third polyhydroxystyrene 
having a weight-average molecular weight of 8000, of which the Mw:Mn value 
representing the molecular weight distribution was 4.5 and 39% of the 
hydroxy groups were substituted by tert-butyloxycarbonyloxy groups, 
replacement of the second polyhydroxystyrene with the same amount of a 
fourth polyhydroxystyrene having a weight-average molecular weight of 
8000, of which the Mw:Mn value representing the molecular weight 
distribution was 4.5 and 39% of the hydroxy groups were substituted by 
ethoxyethoxy groups and replacement of 
.alpha.-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide with the same 
amount of .alpha.-(p-toluenesulfonyloxyimino)-4-methoxybenzyl cyanide. 
The results of the evaluation tests were that the photosensitivity of the 
composition was 4 mJ/cm.sup.2 and the heat resistance test of the 
patterned resist layer indicated that collapsing along the shoulders of 
the line-patterned resist layer was found when the heating temperature was 
120.degree. C. while the cross sectional profile of the line-patterned 
resist layer of 0.23 .mu.m line width examined with a scanning electron 
microscope was wavy indicating a strong influence of standing waves. 
Comparative Example 2 
The formulation of the positive-working chemical-sensitization photoresist 
composition and the evaluation procedures of the same were substantially 
the same as in Example 1 except for the replacement of 
.alpha.-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide with the same 
amount of .alpha.-(p-toluenesulfonyloxyimino)-4-methoxybenzyl cyanide. 
The results of the evaluation tests were that the photosensitivity of the 
composition was 5 mJ/cm.sup.2 and the heat resistance test of the 
patterned resist layer indicated that no collapsing along the shoulders of 
the line-patterned resist layer was found when the heating temperature was 
120.degree. C. or lower while the cross sectional profile of the 
line-patterned resist layer of 0.22 .mu.m line width examined with a 
scanning electron microscope was wavy indicating a strong influence of 
standing waves. 
Comparative Example 3 
The formulation of the positive-working chemical-sensitization photoresist 
composition and the evaluation procedures of the same were substantially 
the same as in Example 1 except for the replacement of the first 
polyhydroxystyrene with the same amount of the third polyhydroxystyrene as 
used in Comparative Example 1 and replacement of the second 
polyhydroxystyrene with the same amount of the fourth polyhydroxystyrene 
as used in Comparative Example 1. 
The results of the evaluation tests were that the photosensitivity of the 
composition was 4 mJ/cm.sup.2 and the heat resistance test of the 
patterned resist layer indicated that collapsing along the shoulders of 
the line-patterned resist layer was found when the heating temperature was 
120.degree. C. while the cross sectional profile of the line-patterned 
resist layer of 0.23 .mu.m line width examined with a scanning electron 
microscope was orthogonal and standing upright on the substrate surface 
without waviness. 
EXAMPLE 2 
A negative-working chemical-sensitization photoresist composition in the 
form of a uniform solution was prepared by dissolving, in 560 parts of 
propyleneglycol monomethyl ether, 100 parts of a first copolymer of a 
85:15 by moles combination of hydroxystyrene and styrene having a 
weight-average molecular weight of 2500, of which the Mw:Mn value 
representing the molecular weight distribution was 1.5, 10 parts of a urea 
resin (Mx-290, supra), 1 part of a melamine resin (Mx-750, supra) and 3 
parts of .alpha.-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide. 
A silicon wafer was uniformly coated with the thus prepared photoresist 
solution on a spinner followed by drying at 100.degree. C. for 90 seconds 
to give a dried photoresist layer having a thickness of 0.7 .mu.m. The 
resist layer was exposed patternwise to KrF excimer laser beams on the 
minifying projection exposure machine (Model NSR-2005EX8A, supra) followed 
by a post-exposure baking treatment at 130.degree. C. for 90 seconds and 
then subjected to a development treatment in a 2.38% by weight aqueous 
solution of tetramethylammonium hydroxide at 23.degree. C. for 65 seconds 
followed by rinse for 30 seconds with water and drying. 
The minimum exposure dose representing the photo-sensitivity of the 
composition for the incipient pattern formation was 8 mJ/cm.sup.2. The 
cross sectional profile of the line-patterned resist layer having a line 
width of 0.30 .mu.m as examined on a scanning electron microscope was 
excellently orthogonal and standing upright on the substrate surface 
without waviness. 
Comparative Example 4 
The formulation of the negative-working chemical-sensitization photoresist 
composition and the evaluation procedures of the same were substantially 
the same as in Example 2 excepting for the replacement of the first 
copolymer of hydroxystyrene and styrene with the same amount of a second 
copolymer of hydroxystyrene and styrene in a molar ratio of 85:15 having a 
weight-average molecular weight of 2500, of which the Mw:Mn value 
representing the molecular weight distribution was 4.0 and replacement of 
.alpha.-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide with the same 
amount of .alpha.-(p-toluenesulfonyloxyimino)-4-methoxybenzyl cyanide. 
The results of the evaluation tests were that the photosensitivity of the 
composition was 10 mJ/cm.sup.2 and the cross sectional profile of the 
line-patterned resist layer of 0.35 .mu.m line width examined with a 
scanning electron microscope was wavy indicating a strong influence of 
standing waves. Line-patterned resist layers having a line width of 0.30 
.mu.m or smaller could not be formed on the substrate surface. 
Comparative Example 5 
The formulation of the negative-working chemical-sensitization photoresist 
composition and the evaluation procedures of the same were substantially 
the same as in Example 2 except for the replacement of 
.alpha.-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide with the same 
amount of .alpha.-(p-toluenesulfonyloxyimino)-4-methoxybenzyl cyanide. 
The results of the evaluation tests were that the photosensitivity of the 
composition was 12 mJ/cm.sup.2 and the cross sectional profile of the 
line-patterned resist layer of 0.30 .mu.m line width examined with a 
scanning electron microscope was wavy indicating a strong influence of 
standing waves. 
Comparative Example 6 
The formulation of the negative-working chemical-sensitization photoresist 
composition and the evaluation procedures of the same were substantially 
the same as in Example 2 except for the replacement of the first copolymer 
of hydroxystyrene and styrene with the same amount of the second copolymer 
of hydroxystyrene and styrene as used in Comparative Example 4. 
The results of the evaluation tests were that the photosensitivity of the 
composition was 7 mJ/cm.sup.2 and the cross sectional profile of the 
line-patterned resist layer of 0.35 .mu.m line width examined with a 
scanning electron microscope was orthogonal and standing upright on the 
substrate surface without waviness. Line-patterned resist layers having a 
line width of 0.30 .mu.m or smaller could not be formed on the substrate 
surface. 
EXAMPLE 3 
A negative-working chemical-sensitization photoresist composition in the 
form of a uniform solution was prepared by dissolving, in 400 parts of 
propyleneglycol monomethyl ether, 100 parts of a first novolac resin 
prepared by the condensation reaction of a 6:4 by moles combination of m- 
and p-cresols with formaldehyde having a weight-average molecular weight 
of 12000, of which the Mw:Mn value representing the molecular weight 
distribution was 3.5, 10 parts of the urea resin (Mx-290, supra), 1 part 
of the melamine resin (Mx-750, supra) and 3 parts of 
.alpha.-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide. 
A silicon wafer was uniformly coated with the thus prepared photoresist 
solution on a spinner followed by drying at 90.degree. C. for 90 seconds 
on a hot plate to give a dried photoresist layer having a thickness of 2.0 
.mu.m. The resist layer was exposed patternwise to the i-line ultraviolet 
light of 365 nm wavelength on a minifying projection exposure machine 
(Model NSR-2005i10D, manufactured by Nikon Co.) followed by a 
post-exposure baking treatment at 100.degree. C. for 90 seconds and then 
subjected to a development treatment in a 2.38% by weight aqueous solution 
of tetramethylammonium hydroxide at 23.degree. C. for 65 seconds followed 
by rinse for 30 seconds with water and drying. 
The results of the evaluation tests were that the photosensitivity of the 
composition for the incipient pattern formation was 25 mJ/cm.sup.2 and the 
cross sectional profile of the line-patterned resist layer of 2 .mu.m line 
width examined with a scanning electron microscope was orthogonal and 
standing upright on the substrate surface without waviness. 
Comparative Example 7 
The formulation of the negative-working chemical-sensitization photoresist 
composition and the evaluation procedures of the same were substantially 
the same as in Example 3 except for the replacement of the first novolac 
resin with the same amount of a second novolac resin prepared from the 
same m- and p-cresol mixture and having a weight-average molecular weight 
of 10000, of which the Mw:Mn value representing the molecular weight 
distribution was 5.6, and replacement of 
.alpha.-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide with the same 
amount of .alpha.-(p-toluenesulfonyloxyimino)-4-methoxybenzyl cyanide. 
The results of the evaluation tests were that the photosensitivity of the 
composition was 30 mJ/cm.sup.2 and the cross sectional profile of the 
line-patterned resist layer of 2 .mu.m line width examined with a scanning 
electron microscope was wavy indicating a strong influence of standing 
waves. 
Comparative Example 8 
The formulation of the negative-working chemical-sensitization photoresist 
composition and the evaluation procedures of the same were substantially 
the same as in Example 3 except for the replacement of 
.alpha.-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide with the same 
amount of .alpha.-(p-toluenesulfonyloxyimino)-4-methoxybenzyl cyanide. 
The results of the evaluation tests were that the photosensitivity of the 
composition was 25 mJ/cm.sup.2 and the cross sectional profile of the 
line-patterned resist layer of 2 .mu.m line width examined with a scanning 
electron microscope was wavy indicating a strong influence of standing 
waves. 
Comparative Example 9 
The formulation of the negative-working chemical-sensitization photoresist 
composition and the evaluation procedures of the same were substantially 
the same as in Example 3 except for the replacement of the first novolac 
resin with the same amount of the second novolac resin as used in 
Comparative Example 7. 
The results of the evaluation tests were that the photosensitivity of the 
composition was 30 mJ/cm.sup.2 and the cross sectional profile of the 
line-patterned resist layer of 2 .mu.m line width examined with a scanning 
electron microscope was orthogonal and standing upright on the substrate 
surface without waviness. 
EXAMPLE 4 
A negative-working chemical-sensitization photoresist composition in the 
form of a uniform solution was prepared by dissolving, in 500 parts of 
propyleneglycol monomethyl ether acetate, 100 parts of the same copolymer 
of hydroxystyrene and styrene as used in Example 2, 15 parts of a melamine 
resin (Mw-100LM, a product by Sanwa Chemical Co.), 3 parts of 
.alpha.-(methylsulfonyloxyimino)benzyl cyanide and 4 parts of 
.alpha.-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide. 
A silicon wafer having an anti-reflection coating film was uniformly coated 
with the thus prepared photoresist solution on a spinner followed by 
drying at 90.degree. C. for 90 seconds on a hot plate to give a dried 
photoresist layer having a thickness of 0.80 .mu.m. The resist layer was 
exposed patternwise to the i-line ultraviolet light of 365 nm wavelength 
on the minifying projection exposure machine (Model NSR-2005i10D, supra) 
followed by a post-exposure baking treatment at 100.degree. C. for 90 
seconds and then subjected to a development treatment in a 2.38% by weight 
aqueous solution of tetramethylammonium hydroxide at 23.degree. C. for 65 
seconds followed by rinse for 30 seconds with water and drying. 
The results of the evaluation tests were that the photosensitivity of the 
composition for the incipient pattern formation was 30 mJ/cm.sup.2 and the 
cross sectional profile of the line-patterned resist layer of 0.30 .mu.m 
line width examined with a scanning electron microscope was orthogonal and 
standing upright on the substrate surface without waviness.