Photoactive esterification product of a diazooxide compound and a curcumin dye and photoresist materials with product

The subject invention involves reduction of light reflection into a photoresist coating over a reflective substrate by the use of a photoactive compound in a photoresist formulation that is the reaction product of a diazooxide and curcumin.

BACKGROUND OF THE INVENTION 
1. Introduction 
This invention relates to novel photoactive compounds and to photoresists 
using said photoactive compounds. More particularly, this invention 
relates to positive working photoresists that possess light attenuating 
capability when exposed to near ultraviolet to visible radiation and use 
an esterification product of a diazooxide and curcumin dye as the 
photoactive compound. 
2. Description of the Prior Art 
Photoresist compositions are known in the art and are described in numerous 
publications including De Forest, Photoresist Materials and Processes, 
McGraw-Hill Book Company, New York, 1975. Photoresists comprise coating 
produced from solution or applied as a dry film which, when exposed to 
light of the proper wavelength, are chemically altered in their solubility 
to certain solvents (developers). Two types are known. The negative acting 
photoresist is initially a mixture which is soluble in its developer but 
following exposure to activating radiation, becomes insoluble in developer 
thereby defining a latent image. Positive working photoresists work in the 
opposite fashion, light exposure making the resist soluble in developer. 
Positive working photoresists are more expensive than negative working 
photoresists but are capable of providing superior image resolution. For 
example, positive working photoresists can be developed to yield relief 
images with a line width as low as 1 micron or less. In addition, 
considering the cross section of a photoresist image, the channels formed 
in the photoresist by development have square corners and side walls with 
only minimal taper. 
Most positive working photoresists comprise a photoactive compound in a 
film forming polymeric binder. Photoactive compounds or sensitizers, as 
they are often called, most frequently used are esters and amides formed 
from o-quinone diazide sulfonic and carboxylic acids. These esters and 
amides are well known in the art and described by De Forest, supra, pages 
47 through 55, incorporated herein by reference. These light sensitive 
compounds, and the methods used to make the same, are all well documented 
in prior patents including German Pat. No. 865,140 and U.S. Pat. Nos. 
2,767,092; 3,046,110; 3,046,112; 3,046,119; 3,046,121; 3,046,122 and 
3,106,465. Additional sulfonamide sensitizers that have been used in the 
formulation of positive working photoresists are shown in U.S. Pat. No. 
3,637,384. These materials are formed by the reaction of a suitable 
diazide of an aromatic sulfonyl chloride with an appropriate resin amine. 
Methods for the manufacture of these sensitizers and examples of the same 
are shown in U.S. Pat. No. 2,797,213. Other positive working diazo 
compounds have been used for specific purposes. For example, a diazo 
compound used as a positive working photoresist for deep U.V. lithography 
in Meldrum's diazo and its analogues as described by Clecak et al, 
"Technical Disclosure Bulletin," Vol. 24, No. 4, September 1981, IBM 
Corp., pp. 1907 and 1908. An o-quinone diazide compound suitable for laser 
imaging is shown in U.S. Pat. No. 4,207,107. 
The resin binders most frequently used with the o-quinone diazides in 
commercial practice are the alkali soluble phenol formaldehyde resins 
known as the Novolak resins. Photoresists using such polymers are 
illustrated in U.K. Patent No. 1,110,017. These materials are the product 
of a reaction of a phenol and formaldehyde under conditions whereby a 
thermoplastic polymer is formed with a melting point of about 125.degree. 
C. Novolaks with melting points well in excess of 125.degree. C. are known 
but are not generally used in photoresist formulations because they are 
often brittle or have other properties limiting their use. 
Another class of binders used with the o-quinone diazides are the 
homopolymers and copolymers of vinyl phenol. Photoresists of this nature 
are disclosed in U.S. Pat. No. 3,869,292. It is believed that photoresists 
using binders of polymers formed from vinyl phenols have not been used in 
commerce. 
Another positive resist known to the art utilizes a resin that is a 
partially aqueous soluble imidized acrylic polymer in a non aqueous 
solvent. Such a resist is disclosed in U.S. Pat. No. 4,524,121. The 
aqueous soluble, imidized acrylic polymers, known in the art as 
polyglutarimides, can be dissolved in a non-reactive, non-aqueous solvent 
to form a positive resist that can be deposited as an adherent film on a 
substrate. Such films are capable of high image resolution. 
Other suitable binders for positive acting photoresists include the 
terpolymers of an alkyl acrylate, a styrene and an acid as disclosed in 
U.S. Pat. No. 3,637,384 and the polyamic condensation products of an 
aromatic dianhydride and an aromatic di-primary amine as disclosed in U.S. 
Pat. No. 4,093,461. 
All of the aforesaid references are incorporated herein by reference for 
their teachings of photoactive compounds, binders and photoresist 
formulations. 
Photoresists of the type described above are used in integrated circuit 
fabrication where significant effort has been expended on increasing the 
resolution capabilities of the photoresists to enable a greater number of 
circuits to be placed on a single chip. This increase in circuit density 
increases the potential complexity and speed of the resulting integrated 
circuit. 
Present techniques in optical projection printing can resolve on micron 
lines in photoresists with good line width control when flat, low 
reflectivity substrates are used. However, when exposing resists on 
substrates with surface topography, there are resist-controlled problems 
introduced by optical reflections and by resist thickness non-uniformity. 
Reflection of light from the substrate photoresist interface produces 
variations in the light intensity in the photoresist during exposure 
resulting in non-uniform line width. Light can scatter from the interface 
into regions of the resist where no exposure was intended resulting in a 
narrowing of the line width. The amount of scattering and reflection will 
typically vary from region to region resulting in line width 
non-uniformity. 
To eliminate the effects of chromatic aberration, monochromatic or 
quasi-monochromatic light is commonly used in photoresist projection 
techniques to expose the photoresist. Unfortunately, the effects of 
interface reflections on resolution is particularly significant when 
monochromatic or quasi-monochromatic light is used to expose the 
photoresist. When such light reflects from the substrate photoresist 
interface, the reflected light interferes with the incident light to form 
standing waves within the photoresist. In the case of highly reflective 
substrate regions, the resulting large standing wave ratio creates thin 
layers of under exposed resist at the standing wave minima. The under 
exposed layers can prevent complete photoresist development causing a 
jagged resist profile. Part of the reflected light also reflects back to 
the substrate from the top surface of the resist. Such multiple reflection 
of the incident light between the top and bottom surfaces of the 
photoresist layer result in a resonance affecting the light intensity 
within the resist. The time required to expose the photoresist is 
generally an increasing function of photoresist thickness because of the 
increase total amount of light required to expose an increased amount of 
photoresist. However, because of the resonant affect, the time of exposure 
also includes a harmonic component which varies between successive maximum 
and minimum values as the resist thickness varies through a quarter 
wavelength of the incident light. If the photoresist thickness is 
non-uniform, there will be a non-uniform exposure resulting in variable 
line width control. 
The prior art has reduced scattering and reflection within photoresist 
layers by addition of dyes to photoresist compositions that absorb at or 
near the wavelength used to expose the photoresist. Typical dyes that have 
been used for this purpose include the Coumarin dyes, methyl orange and 
methanil yellow. These dyes absorb at the conventional exposure wavelength 
of 436 nm. However, it has been found that the addition of such dyes to 
photoresist compositions create other problems. For example, in some 
cases, the dye in a photoresist coating composition may cause striations 
in the final coating. In addition, shelf life problem may be encountered 
due to dye precipitation during storage. Further, because of limited 
solubility, such dyes can only be added to photoresist formulations in 
concentrations inadequate to fully attenuate reflected light. In this 
respect, because the dye absorbs at the activating radiation for the 
photoresist, the presence of the dye results in a requirement for longer 
exposure time or greater exposure intensity, or alternatively, dissolution 
rate of the photoresist during development is inhibited. For this reason 
even if the dye could be dissolved in the photoresist in greater 
concentration, the dye in greater concentration may render the photoresist 
inoperative. 
Due to problems arising from addition of a dye directly to a photoresist 
formulation, the art has attempted to use dyes to absorb reflected light 
by means other than by direct addition to the formulation. One method is 
disclosed by H. A. Koury and K. V. Patel, Anti-Interference Phenomena 
Coating, IBM Technical Disclosure Bulletin, Vol. 13, No. 1, p. 38, June, 
1970 where a thin ultraviolet light-absorbing layer containing a dye such 
as the aforesaid methyl orange or methanil yellow is deposited at the 
substrate-resist interface and is overcoated with the photoresist layer. 
Another method of utilizing a dye is disclosed in U.S. Pat. No. 4,362,809 
where the substrate surface is covered with a bottom layer of resist 
containing a dye of a thickness sufficient to produce a planar surface. 
The top photoresist layer functions as a portable conformable mask. The 
two photoresist layers are selected to be sensitive to differing 
wavelengths of activating radiation. The top resist layer comprising the 
portable conformable mask is exposed and developed to produce a mask 
opaque to deep ultraviolet light. The bottom layer is then exposed through 
the mask with deep ultraviolet light and developed to produce the desired 
photoresist pattern. The dye in the bottom layer absorbs within the range 
of wavelengths used to expose the top resist layer to reduce problems due 
to substrate resist interface reflections. 
The above cited references are incorporated herein for their teachings of 
dyes in resist layers. 
Copending U.S. patent application Ser. No. 06/922,391 filed Oct. 23, 1986, 
incorporated herein by reference, and assigned to the same assignee as the 
subject application, is directed to a photoresist formulation containing 
the dye curcumin for the purpose of absorbing light within a wavelength of 
400 to 460 nm, the wavelength used to form the latent image within the 
photoresist layer. Curcumin is said to significantly reduce reflection 
from a photoresist film-substrate interface during exposure of the 
photoresist film to activating radiation. The use of curcumin is said to 
be a significant improvement over other dyes capable of absorbing within 
the same wavelength because it is substantially more soluble than other 
dyes used for similar purpose. Because of enhanced solubility, the dye can 
be used in greater concentration than other dyes whereby it is capable of 
absorbing a greater quantity of reflected light. In addition, it can be 
used in concentrations lower than its solubility limit in the photoresist 
formulation thereby avoiding precipitation during storage. Further, though 
the dye absorbs at the proper wavelength, and does prevent reflection, it 
does not decrease dissolution of the resist during development to the same 
extent as other dyes and for this reason, can be used in higher 
concentration than other dyes. 
SUMMARY OF THE INVENTION 
The subject invention is an improvement over the above-cited copending 
patent application Ser. No. 06/922,391. The invention is directed to a new 
class of compounds that comprise the esterification product of a 
diazooxide of an aromatic sulfonic acid and curcumin. In addition, the 
invention is directed to a photoresist formulation responsive to 
activating radiation within a wavelength range of from about 200 to 460 nm 
comprising a polymer binder containing the aforesaid esterification 
product. The esterification product functions both as the photoactive 
compound and as a dye capable of absorbing reflected light at the 
wavelength used to expose the photoresist. 
The use of the esterification product of the diazooxide and curcumin as the 
photoactive compound and the dye is an improvement over the use of each 
individually because the concentration of the dye can be increased beyond 
its normal solubility limit since it is chemically combined with the 
photoactive compound. Moreover, its concentration may be more easily 
controlled in the photoresist formulation because it is a reaction product 
formed in accordance with a known chemical reaction. Further, dye 
precipitation during storage as encountered by the prior art is avoided 
because the dye is held in the formulation and in solution by its chemical 
combination with the diazooxide. Finally, by chemical combination of the 
dye with the diazooxide, photoresist manufacture is simplified and cost of 
manufacture is reduced. 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The photoresists of this invention are compositions responsive to 
activating radiation within a wavelength varying from about 200 to about 
460 nm and comprising a polymeric binder and a photoactive compound that 
is the esterification product of a diazooxide and curcumin. Typical 
examples of such photoresists are alkali soluble, positive acting 
photoresists utilizing either a novolak resin or a polyvinyl phenol binder 
activated with a photoactive diazooxide compound for imaging. Another 
example of photoresists within the scope of the invention are those 
formulated from a polyglutarimide. Polyglutarimide photoresists do not 
require a photoactive compound for imaging but often contain a diazooxide 
photoactive compound to increase the reactivity of the photoresist. 
Polyglutarimide photoresists containing a diazooxide photoactive compound 
are within the scope of the subject invention. Components of the 
photoresists that are the subject of the invention, the concentrations of 
the components and solvents required to form coating compositions from the 
photoresists are described in the prior art as are methods used to coat 
and image the same. U.K. Patent No. 1,110,017 cited above describes 
photoresists formulated using novolak resin binders. U.S. Pat. No. 
3,869,292 cited above describes photoresists using polyvinyl phenol resin 
binders. U.S. Pat. No. 4,524,121 cited above described photoresists 
formulated from polyglutarimides. U.S. Pat. No. 3,637,384 cited above 
described photoresists formulated from specific terpolymers. U.S. Pat. No. 
4,093,461 cited above discloses photoresists formulated from polyamic 
condensation products. 
In accordance with the invention, a photoactive diazooxide is esterified 
with the dye curcumin and the reaction product is used in the photoresist 
as both the light sensitive compound and the dye used to absorb reflected 
light. Curcumin [1,7-bis (4-hydroxy-3-methoxy 
phenyl)-1,6-heptadiene-3,5-dione], is also known as turmeric yellow and 
diferuloylmethane. It is described and discussed in numerous references 
including Vogel, Ann. 44, 297 (1842); Perkin, Phipps, J. Chem. Soc. 
(Trans.) 85,I, 64 (1904); Rao, Shintre, J. Soc. Chem. Ind. 47, 54T, 
(1928); Lampe, Ber. 51, 1347 (1918); and Stieglitz, Horn. German Patent 
No. 859,145, (1952). 
The reaction of diazo oxides with aromatic compounds having pendant 
hydroxyl groups is known in the art. Such reactions are shown in U.S. Pat. 
Nos. 3,046,118 and 3,046,121 incorporated herein by reference for reaction 
conditions and reactants. The diazooxide used for such reactions may be 
represented by the formula: 
##STR1## 
where X and X' are N.sub.2 or O and are different from each other, Y is 
hydrogen or halogen and Y' is halogen, preferably chlorine. Curcumin has 
the formula: 
##STR2## 
from which it can be seen that the compound has two pendant hydroxyl 
groups or sites where esterification between the diazooxide and the dye 
can take place. The reaction involves the halide of the sulfonyl halide 
and the hydroxyl groups of the curcumin. Since curcumin possesses two 
hydroxyl groups, the reaction product may be a monoester, a diester or a 
mixture of the two dependent upon reaction conditions and the molar ratio 
of the diazooxide to the curcumin. 
In accordance with the preferred embodiment of the invention, the 
predominant reaction product is the diester whereby the preferred molar 
ratio of the diazooxide to the curcumin is slightly in excess of 2 to 1, 
for example 2.1 to 1. 
The photoactive esterification products of the diazooxide and the curcumin 
are formed by reacting one or two moles of the appropriate [diazo oxide] 
sulfonyl chloride [RSO.sub.2 Cl] with one mole of a dihydroxy compound 
[HO--X--OH] in a suitable solvent medium. General reactions follow: 
EQU RSO.sub.2 Cl+HO--X--OH.fwdarw.RSO.sub.2 --O--X--OH+HCl 
EQU 2 RSO.sub.2 Cl+HO--X--OH.fwdarw.RSO.sub.2 --O--X--O--SO.sub.2 R+2 HCl 
Various hydrogen halide acceptors may be utilized to neutralize the 
hydrogen chloride by-product from this condensation reaction, such as 
sodium carbonate, sodium bicarbonate, and the like, or organic bases such 
as primary, secondary, or tertiary amines, or organic bases such as 
tetramethylammonium hydroxide, tetraethylammonium hydroxide, and the like. 
Examples of general reactions are as follows: 
EQU 2 HCl+Na.sub.2 CO.sub.3 .fwdarw.2 NaCl+H.sub.2 O+CO.sub.2 
EQU HCl+(CH.sub.3).sub.3 N.sup.+ OH.sup.- .fwdarw.(CH.sub.3).sub.3 NH.sup.+ 
Cl.sup.- 
EQU HCl+(CH.sub.3).sub.3 N.sup.+ OH.sup.- .fwdarw.(CH.sub.3).sub.3 N.sup.+ 
Cl.sup.- +H.sub.2 O 
The condensation reaction media range from aqueous (with or without a 
suitable organic co-solvent, such as dioxane), wherein inorganic 
carbonates or bicarbonates perform the hydrogen halide acceptor function, 
to suitable organic solvents wherein organic bases are more compatible. In 
all cases, solvent medium selection is based on the ability to dissolve 
both reactants prior to addition of the hydrogen halide acceptor. 
The purified diazo compounds based on the dihydroxy ballasting group are 
brilliant yellow crystalline solids and, in general, are difficult to 
dissolve in all but the most polar solvents. For example, they dissolve 
more readily in dimethylformamide, N-methyl-1-pyrrolidone, ethyleneglycol 
monomethylether, propylene glycol monomethylether acetate, dioxane, or 
combinations of such solvents. In many cases, it is advisable to use 
admixtures of difficulty soluble products and more readily soluble 
products. Such combinations of products are often of advantage because 
crystalline formations from the solution may be avoided and smoother 
coatings are obtained when combined with a suitable resin system such as 
is practiced in the preparation of lithographic printing plates or 
photoresist films. Further, the use of combinations of solvents may 
improve the clarity and smoothness of such films as is known to the 
organic finishing and coating arts. 
Examples of esterification products within the scope of the invention 
include: 
##STR3## 
To form a photoresist, the photoactive compound of the invention is added 
to a resin binder in an amount ranging between 0.1 weight percent of total 
photoresist solids and the solubility limit of the photoactive compound in 
the photoresist formulation. In addition, a conventional photoactive 
compound (one that does not incorporate the dye in its structure) may be 
added to the photoresist. The use of the conventional photoactive compound 
in combination with the esterification product of the invention is 
believed to provide increased photospeed. The conventional photoactive 
compound may be used in a concentration of up to 90 percent of the total 
of the photoactive compound of this invention, and a preferred range 
varies between 10 and 40 percent of the total of the photoactive 
components. 
The binder may be a resin such as novolak resin, a polyvinyl phenol or a 
polyglutarimide, all as described above. Photoactive compound 
concentrations at the upper end of the solubility range are preferred 
because higher concentrations result in greater light sensitivity and 
enhanced absorption of reflected light. However, it is also preferred that 
the concentration be below the solubility limit of the photoactive 
compound in the photoresist formulation so that precipitation of compound 
does not occur during storage. A preferred, though generalized 
concentration range, varies from about 1.0 to 35.0 weight percent of the 
total photoresist solids. The range is generalized because the exact 
concentration is dependent upon the specific composition of the 
photoresist, especially the solvent for the photoresist and the polymer 
binder. 
The photoactive compound is blended with the binder with both materials 
dissolved in a suitable solvent in conventional manner. If a dry film 
photoresist is desired, a liquid photoresist is formulated and then cast 
into a dry film in conventional manner. 
During exposure of the photoresist to activating radiation, the photoactive 
compound that is the esterification product with the dye is both the 
source of photo activity and the dye that reduces reflection of light from 
the photoresist and substrate interface. The degree of reduction is a 
function of the concentration of the photoactive compound in the 
photoresist formulation. Since the curcim moiety may be present in the 
formulation in greater concentration because it is part of the photoactive 
compound, the increased concentration increases total absorption and 
reduced reflection. Moreover, since the photoactive compound contains the 
dye that absorbs at the exposure wavelength, better image definition is 
obtained. 
Following preparation of the photoresist composition, the photoresist may 
be used in art recognized manner. For example, the photoresist may be a 
dry film photoresist applied to a substrate using heat and pressure. 
Alternatively, the photoresist may be applied to a surface in the form of 
a liquid coating composition. When applied as a liquid coating 
composition, it is coated onto the substrate in conventional manner such 
as by spin coating, roller coating, etc. The liquid photoresist coating is 
then dried and typically soft baked to yield a dry photoresist layer. 
Thereafter, the dry layer, whether formed from a liquid coating 
composition, or applied as a dry film, is exposed and developed using a 
developer capable of differentiating between light exposed and light 
unexposed areas. Typical developers comprise aqueous alkaline solutions. A 
typical prior art developer is disclosed in copending U.S. patent 
application Ser. No. 846,824 assigned to the same assignee as the subject 
application and incorporated herein by reference for its teachings of 
developer compositions and methods for use of the same. 
The photoresist of the invention may be used as a stand alone photoresist 
layer. In such application, the resist is applied as a single resist 
layer. Alternatively, the photoresist may be used as one or more layers of 
a multilayer photoresist such as in the embodiment described in U.S. Pat. 
No. 4,362,809 incorporated herein by reference. In a preferred embodiment 
of the invention, the photoresist is used as one of several layers in a 
multilayer process such as that disclosed in the aforesaid U.S. Pat. No. 
4,362,809. 
The following examples better illustrate the invention. Example 1 
constitutes the most preferred embodiment of the invention.

EXAMPLE 1 
1,7-Bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione 
2-Diazo-1-oxo-5-naphthalene disulfonate [compound 9] 
A stirred solution of 
1,7-Bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione [20.7 g] and 
2-Diazo-1-oxonaphthalene-5-sulfonyl chloride [31.7 g] in acetone [675 ml] 
is treated slowly with a solution of triethylamine [12.5 g] in acetone 
[225 ml] over a period of two hours at room temperature. The reaction mass 
is allowed to stir an additional 15 minutes, and is then filtered to 
remove by-product triethylamine hydrochloride. The filtrate is then poured 
into methanol [675 ml] containing 10% sulfuric acid [56.25 ml]. After 
stirring the mixture for one hour, deionized water [1,680 ml] is added 
over a 45 minute period with continued stirring, resulting in the 
formation of a flocculent precipitate. The product was isolated by vacuum 
filtration and washed with deionized water [1000 ml]. The moist filter 
cake was slurried in deionized water [900 ml] and stirred overnight. It 
was then filtered, washed with deionized water, and dried at 40.degree. C. 
overnight. A 95% product yield was obtained. 
EXAMPLE 2 
1,7-Bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione 
2-Diazo-1-oxo-5-naphthalene sulfonate [compound 10] 
This compound was prepared by combining 
1,7-Bis-(4-hydroxy-3-methoxy-phenyl)-1,6-heptadiene-3,5-dione [29.9 g] and 
2-Diazo-1-oxonapththalene-5-sulfonyl chloride [21.8 g] in acetone [675 ml] 
and treated slowly with a solution of triethylamine [9.0 g] in acetone 
[225 ml] over a period of two hours at room temperature. The reaction mass 
is allowed to stir an additional 15 minutes, and is then filtered to 
remove by-product triethylamine hydrochloride. The filtrate is poured into 
methanol [485 ml] containing 10% sulfuric acid [40.6 ml]. After stirring 
the mixture for one hour, deionized water 2,200 ml] is added over a period 
of one hour with continued stirring, resulting in the formation of a 
flocculent precipitate. The product was isolated by vacuum filtration and 
washed with deionized water [1000 ml]. The moist filter cake was slurried 
in deionized water [300 ml] and stirred overnight. It was then filtered, 
washed with deionized water, and dried at 40.degree. C. overnight. A 78% 
product yield, corresponding to the above formula, was obtained. 
EXAMPLE 3 
1,7-Bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione 
2-Diazo-1-oxo-4-naphthalene disulfonate [compound 7] 
This compound was prepared as in Example 1, substituting 
2-Diazo-1-oxonaphthalene-4-sulfonyl chloride for 
2-Diazo-1-oxonaphthalene-5-sulfonyl chloride. This procedure gave a 69% 
product yield. 
EXAMPLE 4 
1,7-Bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione 
2-Diazo-1-oxo-4-naphthalene sulfonate [compound 8] 
This compound was prepared following the procedure in Example 2, 
substituting 2-Diazo-1-oxonaphthalene-4-sulfonyl chloride for 
2-Diazo-1-oxonaphthalene-5-sulfonyl chloride. This procedure gave a 73% 
product yield. 
EXAMPLE 5 
A positive-working photoresist formulation was prepared by first dissolving 
a blend of novolak resins in ethylene glycol dimethyl ether, this solution 
containing 20% to 30% by weight of resin. To this solution, the compound 
disclosed in Example 1 was added in sufficient quantity so as to provide 
adequate inhibition and acceleration of resin dissolution in unexposed and 
exposed areas, respectively, when subjected to an imaging process. The 
above composition is filtered through a 0.2 micrometer pore size filter, 
then spin coated onto silicon wafers using SVG 80 equipment [Silicon 
Valley Group, Inc.] at a spin speed of 5000 rpm. The coated wafers are 
baked in a forced air convection oven at 90.degree. C. for 30 minutes. 
Once cooled, the thickness of the coating was found to be approximately 2 
micrometers. The wafers were then exposed to broadband UV radiation 
through a mask of opaque lines and clear spaces as small as 1.0 
micrometer. After development in MICROPOSIT.RTM. MF-312 CD-27 alkali 
developer [manufactured by Shipley Company, Inc.], the mask image was 
found to be reproduced in the photoresist and had excellent adhesion. 
The claims which follow use the expression "effective amount" in reference 
to the concentration of the esterification product of the photoactive 
compound and the curcumin dye used in the photoresist composition.