GB2413553A

GB2413553A - UV decomposable molecules and a photopatternable monomolecular film formed therefrom

Info

Publication number: GB2413553A
Application number: GB0409606A
Authority: GB
Inventors: Hitoshi Fukushima; Hiroshi Takiguchi; Tatsuya Shimoda; Richard James Bushby; Stephen Evans; J P Jeyadevan; Kevin Critchley
Original assignee: Seiko Epson Corp
Current assignee: Seiko Epson Corp
Priority date: 2004-04-29
Filing date: 2004-04-29
Publication date: 2005-11-02
Also published as: GB0409606D0; CN1715270A

Abstract

Provided is a molecule comprising a structural component (A) which decomposes when irradiated with UV light having a wavelength in the range 254-400 nm (such as an o-nitrobentyl ester), and a structural component (B) which is hydrophobic and/or lipophobic (such as a fluorinated chain). Such a molecule may form all or part of a self-assembled monolayer film on a substrate. Also provided is a monomolecular film coated substrate (10), the film being formed from molecules comprising a structural component (B) which is hydrophobic and/or lipophobic, and a structural component (A) which decomposes (step (2) to (3) in figure 2) when irradiated with UV light having a wavelength in the range 254-400 nm to cleave away a part of the molecule comprising the structural component (B) leaving a residual hydrophilic structural component (C). Such a substrate can be photopatterned by image-wise irradiating it with UV light having a wavelength in the range 254-400 nm through a patterned mask to cleave the coated molecules at the structural component (A) thus removing the structural component (B) from the coated film in the irradiated areas converting them from being hydrophobic and/or lipophobic to hydrophilic. Where the substrate has a hydrophilic surface, the monomolecular film may be formed entirely from the UV decomposable molecules. Otherwise, the film may be that of a coupling compound which comprises a hydrophilic moiety and the latter is subsequently reacted with the UV decomposable molecules (step (1) to (2) in figure 2).

Description

24 1 3553 W Decomposable Molecules and a Photopatternable Monomolecular

Film Formed Therefrom The present invention relates to certain molecules which are susceptible to decomposition by W light particularly those having a hydrophobic and/or lipophobic structural component. Such molecules may be used to form a monomolecular film which can be photopatterned when image- wise exposed to low energy W irradiation.

l0 A number of methods are known for forming patterned films on substrates such as semiconductor substrates. One of these methods is based upon dissolving a photosensitive polymer material in a solvent and then forming a film of this by spin coating on a semiconductor substrate. The resulting film is then irradiated with ultraviolet rays (W) through a patterned mask resulting in the formation of a negative or a positive pattern in the photosensitive polymer film. However, the technique of spin coating is inefficient insofar as up to 99% by weight of the polymer material is discarded during the coating step.

As an improvement of such processes, it has been proposed to form photopatternable films of monomolecular thickness which can be imaged by exposure to W irradiation.

These films are called Self-Assembled Monolayers (SAMs).

Examples of such methods are disclosed in Micropatterning of organosilane self-assembled monolayers using vacuum ultraviolet light at 172 nm: resolution evaluation by Kelvin-probe force microscopy by H. Sugimura et al., in Surface and Coatings Technology (2003) pages 169-170 and Scanning probe nanolithography by H. Sugimura in OYO BUTURI (Applied Physics) (2001), Vol. 70, page 1182. Methods using SAMs reduce wastage of the photopatternable material compared to processes which make use of spin coating. This is because only a very small amount of photosensitive material is needed, i.e. the amount needed to form a monomolecular film of the material.

However, the previously proposed photopatternable SAMs have the disadvantage that they have needed to be exposed to high energy W irradiation for a long period of time in order to be satisfactorily imaged. This means that they have relatively poor processing efficiency. It is desirable therefore to provide an improved material for forming a SAM which can be photopatterned by exposure to low energy W irradiation, that is by exposure to W light having a relatively long wavelength, for a short period of time.

l0 Separately from the above, Dunkin et al, disclose in J. Chem. Soc. Perkin Trans. 2, (2001), page 1414 that an o nitrobenzyl ester derivative absorbs W radiation at approximately 254 nm. This absorption induces photoisomerization and photodecomposition reactions. This is illustrated in the following reaction scheme: :8 o ON,oH[3Ho H'H

OR OR OR

PHOTOISOMERIZATION REACTION

CYCLIZATION I

(ENOLIZATION)-

ASH

O

FOR

R1-NH2 H RON R1' 8'H CO2 0 R=R NHCO The first reaction in the above scheme is the intramolecular enolization reaction of an o-nitrobenzyl ester derivative. This in turn induces intramolecular cyclization. An ester group present at the benzyl group then dissociates thereby forming a compound having an aldehyde and a nitroso group as a decomposition product.

When a carbamic ester linkage is formed at the benzyl group, an amine compound and carbon dioxide are also formed as the other decomposition products.

The present inventors had the idea that derivatives of this type including a photodegradable structure could be incorporated into a SAM useful for photopatterning which could be formed on a variety of different substrate types.

They further had the idea that such a SAM could be arranged to express two different surface properties of on the one hand hydrophobicity and/or lipophobicity and on the other hand hydrophilicity by means of careful molecular design such that when the molecule is subjected to W irradiation, the hydrophobic and/or lipophobic structural component is cleaved away liberating a hydrophilic substituent.

According to a first object, the present invention aims to provide a molecule for inclusion in a SAM which can be photopatterned in a short period of time using low energy W radiation, that is W radiation having a relatively long wavelength.

According to a second object, the present invention aims to provide such a molecule which can be formed into various types of SAMs and used for photopatterning a variety of different types of substrates.

According to a third object, the present invention aims to provide a SAM having two different surface properties, that is initially a hydrophobic and/or lipophobic property but which is converted to a hydrophilic property on W irradiation.

The present inventors found that these objects could be attained by introducing a structural component in a SAM which is decomposed when irradiated with W light having a wavelength in the range 254-400 nm causing cleavage of the molecule whilst at the same time also including a structural component in the SAM which is hydrophobic and/or lipophobic.

Therefore, according to a first aspect, the present invention provides a molecule comprising a structural component (A) which decomposes when irradiated with W light having a wavelength in the range 254-400 nm, and a structural component (B) which is hydrophobic and/or lipophobic.

It is preferred that the structural component (A) is an o-nitrobenzyl ester. This has the advantage of being easily cleaved when irradiated with low energy W light having a relatively long wavelength well within the range of 254-400 nm. It is preferred also that the terminal group bonded to the benzyl group of the o-nitrobenzyl ester should be a succinic imide. This has the advantage of allowing the molecule to be coupled by means of covalent bonding either directly to a substrate surface having suitable functional groups or via a monolayer of a coupling compound previously attached to the substrate surface and which has a functional group reactive with a succinic imide residue.

The structural component (B) is preferably a fluorinated chain which more preferably may be saturated.

The chain may be straight or branched. It may also be perfluorinated which has the advantage of increasing the chain's hydrophobicity.

In this aspect of the present invention, the molecule preferably has the general formula (I): R1 R4 R3 (I) R2 O R O R5 NO2 wherein: R1 independently represents a hydrogen atom or -OR6, wherein R6 is a C1iO alkyl chain; R2 represents an N-hydroxy succinic imide group optionally substituted with a sulfonyl group; R3 represents -X2-(CH2)n-X1, wherein X2 represents -CH2- or -O-, n is O or an integer of 1 to 10, and X1 represents -OZ, -Z or

OZ

- Y-(CH2)m- CH2 OZ wherein:

OZ

Y is -(CH2)- or -O-, Z is a C120 fluoroalkyl group and m is 0 or an integer of 1 to 10; R4 represents -NO2 or a hydrogen atom; and Rs is a hydrogen atom or a C1lO alkyl group.

Preferably the substituent R1 is a methoxy group. The presence of such a substituent has the advantage of causing the o-nitrobenzyl ester structure to absorb W light in the region 330-360 nm, that is W light of very low energy.

Preferred C120 fluoroalkyl groups represented by Z include -(CH2)m(CF2)pF or a branched chain isomer thereof wherein m is as defined above and p is O or an integer of 1 to 9.

A preferred molecule of the above general formula is: N-Q o 3 According to a second aspect, the present invention provides a monomolecular film coated substrate, the film being formed from molecules comprising a structural component (B) which is hydrophobic and/or lipophobic, and a structural component (A) which decomposes when irradiated with W light having a wavelength in the range 254-400 nm to cleave away a part of the molecule comprising the structural component (B) leaving a residual hydrophilic structural component (C).

In the same way as in the first aspect, it is preferred that the structural component (A) is an o-nitrobenzyl ester, and that the structural component (B) comprises a fluorinated chain which may more preferably be saturated.

The fluorinated chain may also be branched and/or perfluorinated.

The hydrophilic structural component (C) preferably includes an amine group or a hydroxyl group. Such groups are advantageous insofar as they can react with a succinic imide to covalently bond with molecules in accordance with the first aspect of the present invention but then cleave when irradiated with UV irradiation to liberate the relatively hydrophilic amine group or hydroxyl group.

The monomolecular film (SAM) of the second aspect is obtainable by coating a substrate with a monomolecular film of a coupling compound (D) which comprises a hydrophilic moiety and subsequently reacting the hydrophilic moiety with a molecule according to the first aspect of the present invention. The substrate may be any suitable material including a metal, a semiconductor or a plastics.

Alternatively, the monomolecular film (SAM) coating the substrate may be formed entirely from the molecules according to the first aspect of the present invention if these are able to satisfactorily adhere to the substrate for instance by means of covalent bonding to suitable pre existing functional groups on the substrate surface. This can in particular be the case if the substrate has a hydrophilic surface.

According to a third aspect, the present invention provides a method of photopatterning the monomolecular film coated substrate according to the second aspect described above which comprises the step of image-wise irradiating the monomolecular film coated substrate with W light having a wavelength in the range 254-400 nm through a patterned mask S to cleave the coated molecules at the structural component (A) thus removing the structural component (B) from the coated film in the irradiated areas converting them from being hydrophobic and/or lipophobic to hydrophilic.

The various aspects of the present invention will now be described in further detail including reference to the Figures of this specification which may briefly be described as follows: Figure 1 illustrates the synthesis of a molecule (compound 1) according to the first aspect of the present invention; Figure 2 illustrates the covalent bonding of a molecule according to the first aspect of the present invention to a coupling compound (D) previously attached to a substrate and their subsequent cleavage when subjected to W irradiation; and Figure 3 illustrates the W irradiation energy distribution which can be used to expose a monomolecular film coated substrate in accordance with the second aspect of the present invention.

Returning to the first aspect of the present invention as discussed above, this relates in its broadest aspect to a molecule comprising a structural component (A) which is decomposed when irradiated with W light having a wavelength in the range 254-400 nm, and a structural component (B) which is hydrophobic and/or lipophobic. Thus the molecule comprises at least two separate structural components. The first of these structural components, labelled (A), is a chemical structure or moiety which decomposes when irradiated with W light having a relatively long wavelength which falls in the range 254-400 nm. It is this structural component which renders the molecule sensitive to W light and thus makes the molecule itself, or a larger molecule into which it is coupled, sensitive to W light and therefore capable of being photopatterned. On the other hand, the structural component (B) is hydrophobic and/or lipophobic resulting in the molecule itself having this property or these properties. As a consequence, a monomolecular film formed from the molecules of the first aspect of the present invention has a hydrophobic and/or lipophobic surface property as does a monomolecular film (SAM) formed by coupling the molecules of the first aspect of the present invention to a monomolecular film of a coupling compound already coated on a substrate.

Molecules in accordance with the first aspect of the present invention can be photopatterned even when irradiated for a short period of time such as 10 seconds to 10 minutes, more preferably 30 seconds to 5 minutes, most preferably 1 to 5 minutes with low energy W light corresponding to a wavelength in the range 254-400 nm. This means that photopatterning can be carried out relatively efficiently insofar as it requires only relatively low energy irradiation.

The structural component (A) which can be decomposed when irradiated with UV light may be an o-nitrobenzyl ester.

The decomposition of such a structural component is set out above in relation to the acknowledged prior art of Dunkin et al. The structural component (B) is hydrophobic and/or lipophobic. The presence of this structural component causes a monomolecular film formed from the molecules to be in turn hydrophobic and/or lipophobic. Suitable examples of the structural component (B) are long chain hydrocarbons and long chain fluorinated carbon chains which may be perfluorinated or substituted by a mixture of fluorine and hydrogen atoms. Preferably such chains are saturated and/or branched, that is they may have a dendritic structure.

Examples of such chains include for example the saturated fluorinated chains -(CH2) n ( CF2)mCF3' -(CH2)nCF[(CF2)mCF3]2 and -(CH2)nC[(CF2)mCF3]3, (where n and m are integers, preferably O to lO and O to 9, respectively).

If the structural component (A) is an o-nitrobenzyl ester, then the structural component (B) can be easily introduced at the pare-position of the benzyl group via an ether bond.

If the structural component (A) is an o-nitrobenzyl ester, then the molecule of the first aspect of the present invention preferably has a succinic imide structure as the terminal group of the benzyl group due to its advantageous reactivity. This enables the resulting molecule to be easily coupled to a substrate which either has suitable surface reactive groups such as hydroxyl or amino groups, or may be coupled to such a substrate by means of a monolayer of a coupling compound (D) previously coated and/or bonded to the substrate which has a functional group reactive with the succinic imide structure such as a hydroxyl or amino group. This enables the molecules of the first aspect of the present invention to be applied to practically any type of substrate such as the surface of a gold substrate which is surface-modified with amino groups, a surface of a semiconductor substrate such as silicon, an organic material surface of a plastics substrate or the surface of an insulating substrate. In this way, a photodegradable SAM can be produced.

For instance, a substrate such as a gold film may be coated with a monolayer of an aminosilane compound such as 3-aminopropyltrimethoxysilane which is then coupled to a molecule according to the first aspect of the present invention including an o- nitrobenzyl ester having a terminal succinic imide residue. Such a coupling mechanism enables the molecules of the first aspect of the present invention to be widely applied to many different types of substrate and so used in photopatterning applications. The coupling compound (D) could have an alternative substituent reactive with a succinic imide residue such as a hydroxyl group.

This coupling concept is more fully illustrated in Figures 2(l) and 2(2). In these Figures, a substrate (lo) S is initially treated with HSCH2CONHCH2(OCH2CH2)6CH2CH2NH2 as a coupling compound (D) which forms a monomolecular film (not illustrated) on the substrate (lo). The film's surface includes reactive amino groups. These amino groups may then be reacted with molecules according to the first aspect of the present invention which bear a succinic imide residue at one terminal which reacts together with the amine substituent of the coupling compound (D) to form a carbamic ester structure. The reaction between the coupling compound and the molecule according to the first aspect of the present invention can be performed for example in an organic solvent such as dichloromethane using trimethylamine as a reaction catalyst. The substrate (lo) may for instance be a metal substrate such as gold or silver since such metal substrates have relatively strong reactivity with thiols and disulphides. Therefore the coupling compounds readily react with the substrate to form a SAM on the substrate surface.

An alternative coupling compound would be ll- aminododecanethiol.

The molecules according to the first aspect of the present invention preferably have the general formula (I): R1 R4 R3 (I) R2 O R O R5 NO2 wherein: Rl independently represents a hydrogen atom or -OR6, wherein R6 is a CllO alkyl chain; ll R2 represents an N-hydroxy succinic imide group optionally R3 represents -X2-(CH2)n-Xl, wherein X2 represents -CH2- or -O-, n is 0 or an integer of l to lo, and Xl represents -OZ, -Z or

OZ

-Y-(cH2)m-CH2 OZ wherein:

OZ

Y is -(CH2)- or -O-, Z is a Cl20 fluoroalkyl group and m is 0 or an integer of l to lo; R4 represents -NO2 or a hydrogen atom; and R5 is a hydrogen atom or a Cll0 alkyl group.

Such compounds are efficiently decomposed even when absorbing a small amount of W radiation but enable a SAM to be formed having a high surface hydrophobic and/or lipophobic property.

It is particularly preferred in the above compounds of formula (I) that the substituent Rl should be a methoxy group (-OCH3), that is a structure in which a methoxy group is bonded to the pare-position with respect to the nitro group. This substitution causes the compound to strongly absorb W radiation in the wavelength range 330-360 nm. It 2s is further preferred that R5 is a hydrogen atom.

It is further preferred in the above compounds of general formula (I) that the substituent Z is -(CH2)m(CF2)pF or a branched chain isomer thereof wherein m is as defined above and p is 0 or an integer of l to 9 If the molecules according to the first aspect of the present invention are coated as a monolayer (a SAM) on a substrate having a hydrophilic surface, then the resulting monomolecular film coated substrate may be directly subjected to photopatterning by exposure to W irradiation.

3s Thus such irradiation will cleave the molecule at the structural component (A) exposing, after rinsing, the hydrophilic surface of the substrate. Areas of the monomolecular film which are masked from irradiation remain hydrophobic and/or lipophobic due to the structural component (B). As a consequence, such a coated substrate is able to demonstrate two different surface properties, that is a hydrophilic surface property in areas which have been subjected to W irradiation and a hydrophobic and/or lipophobic surface property where they have not.

Alternatively, the molecules according to the first aspect of the present invention may be coupled to the surface of a substrate through a coupling compound (D) such as illustrated in Figure 2(2). The resulting SAM has a carbamic ester structure. When the SAM surface is irradiated with W radiation having a wavelength of for instance 365 nm through a photo-mask, photodecomposition of the SAM proceeds quite quickly, in about 30 seconds - 5 minutes, and the carbamic ester structure is decomposed.

Subsequently, the film surface is rinsed with a suitable solvent such as water, and the original amino groups of the coupling compound (D) reappear on the film surface as illustrated in Figure 2(3). As a consequence, a large difference exists in the surface energy between the W irradiated regions of the SAM coated substrate and the non irradiated regions.

In accordance with the above, a monomolecular film or SAM, is obtained whose nettability to a solution and solvent can be significantly altered by subjecting it to image-wise W irradiation. For instance, when the above-described molecules containing a succinic imide residue are used, they may be reacted with a hydroxy thiol, such as 11 hydroxydodecanethiol, by refluxing in acetonitrile as a solvent. This reaction produces a disulphide carbamate.

Subsequently, this derivative may be fixed to a gold substrate to form a monomolecular film thereon. This coated 3s substrate may then be irradiated with W light having a wavelength in the range 254-400 nm in order to bring about a dissociation reaction which results in the cleavage away of the succinic imide derivative leaving only the 11-hydroxydodecanethiol which presents hydroxyl groups on its film surface rendering the irradiated areas of the SAM hydrophilic. This is in contrast to the unirradiated areas of the SAM which remain hydrophobic and/or lipophobic due to the presence of the structural component (B).

As previously described, the second aspect of the present invention provides a monomolecular film coated lo substrate, the film being formed from molecules comprising a structural component (B) which is hydrophobic and/or lipophobic, and a structural component (A) which decomposes when irradiated with W light having a wavelength in the range 254-400 nm to cleave away a part of the molecule comprising the structural component (B) leaving a residual hydrophilic structural component (C).

The monomolecular film (SAM) which is deposited on the substrate will be understood to be a highly functional layer having two possible surface properties, that is an initial hydrophobic and/or lipophobic property, and a hydrophilic property after being subjected to W irradiation. These properties make such a monomolecular film coated substrate suitable for photopatterning by UV irradiation. The structural component (A) and the structural component (B) are the same as described in respect of the first aspect of the present invention above. Accordingly, unless the monomolecular film of the second aspect of the present invention is particularly described in the following, the above description of the molecules of the first aspect of the present invention can be applied.

Turning to the residual hydrophilic structural component (C), this is a hydrophilic substituent group such as an amine group or a hydroxyl group. This group is liberated upon cleavage of the structural component (A) caused by W irradiation. This is particularly illustrated in Figure 2(2) and 2(3). According to this Figure, W irradiation of the monomolecular film coated substrate of Figure 2(2) causes cleavage of the o-nitrobenzyl ester structure. After rinsing away of the residues, the aminesubstituted coupling compound (D) remains resulting in areas of the monomolecular film which have been irradiated being hydrophilic. In contrast, areas masked from the W irradiation will remain hydrophobic due to the chain -OCH2CH2(CF2)5CF3 which constitutes the structural component (B).

The monomolecular film in the second aspect of the present invention is preferably obtainable by coating a substrate with a coupling compound (D) which comprises a hydrophilic moiety and subsequently reacting the hydrophilic moiety with a molecule according to the first aspect of the present invention. Alternatively, where the surface of the substrate is already hydrophilic, the monomolecular film coated substrate according to the second aspect of the present invention may be obtained simply by coating onto the substrate molecules according to the first aspect of the present invention to form a SAM.

Once the monomolecular film coated substrate has been subjected to photopatterning, then for instance a polymer solution containing a functional material may be applied to its surface by conventional techniques such as spin coating or ink jet printing which selectively applies the solution.

The functional material will be deposited over the patterned monomolecular film which in turn allows the functional material to be easily patterned.

As described above, the present invention provides in a third aspect a method of photopatterning a monomolecular film coated substrate as described above which comprises the step of image-wise irradiating the monomolecular film coated substrate with W light having a wavelength in the range 254-400 nm through a patterned mask to cleave the coated molecules at the structural component (A) thus removing the structural component (B) from the coated film in the irradiated areas converting them from being hydrophobic and/or lipophobic to hydrophilic.

Techniques of photopatterning using light irradiation and masks are well known to those working in the field of resist technology.

It will be appreciated that the method according to the third aspect of the present invention allows photopatterning to take place requiring only a monomolecular film coating on a substrate. This therefore solves the problem of substantial wastage referred to in the introduction of this specification when using conventional photosensitive polymer materials applied by spin coating. In addition, the two- stage method of forming a monomolecular film provided by the present invention which includes designing and synthesizing molecules in accordance with the first aspect of the present invention having both a W degradable structure and a hydrophobic and/or lipophobic structural component and then coupling these to a coupling compound (D) via a hydrophilic moiety on the latter provides a widely applicable technique for photopatterning a variety of substrate types.

The following Examples provide further details of the present invention. However, it should be noted that the present invention is in no way limited to the specifics of

these Examples.

Example l

The compound of the formula: '3 ^ _ Flu fat f O2 {F950'3

BAN

(compound l) was prepared in accordance with the synthesis set out in Figure l and its reaction steps l-4.

The spectral data of 1H NMR, 13C NMR, MS, and the like for the material (white solid) synthesized in reaction step (1) are as follows, and this material was identified as 4 (1H, 1H, 2H, 2H-perfluorooctyloxy)-3-methoxy-benzaldehyde (a yield of 30%) .

lH NMR (300 MHz, CDCl3) 9.87 (s, 1H, Ar-H), 7,48-7.43 (m, 2H, Ar-H), 6,59 (d, 1H, Ar-H), 4.43-4.38 (t, 2H), 3,93 (s, 3H), 2.81-2.69 (m, 2H); 13C NMR (75 MHz, CDC13) 191,28, 153.26, 150.35, 131.28, 126.90, 1112.34, 110.02, 61.54, lO 56.47, 31.82, 31.54, 31.25; MS (ES+) 499 ([M+H]+, 55), 454 (20), 391 9220, 279 (5), 241 (5).

The spectral data of 1H NMR, 13C NMR, MS, elemental analysis, and the like for the material (yellow solid) synthesized in reaction step (2) are as follows, and this material was identified as 2-nitro-4-(lH, 1H, 2H, 2H perfluorooctyloxy)-5-methoxy-benzaldehyde (a yield of 80%).

1H NMR (300 MHz, CDC13) 7.64 (s, 1H, Ar-H), 7.43 (s, 1H, Ar H), 4.47-4.43 (t, 2H), 4.01 (s, 3H), 2.86-2.69 (m, 2H); 13C NMR (75 MHz, CDCl3) 188.08, 154.01, 151.17, 126.77, 110.71, 108.91, 91.23, 62.28, 57.17, 31.78, 31.48, 31.21; MS (ES+) 544 ([M+H]+, 100), 514 (15), 410 (15), 282 (10), 178 (10); Anal. Calcd. For C16HloFl3o5N:c 35.35%, H 1.85%, N 2.57%, found C 35.35%, H 1.95%, N 2. 75%.

The spectral data of 1H NMR and 13C NMR for the material (solid) synthesized in reaction step (3) are as follows, and this material was identified as 2-nitro-4-(lH, 1H, 2H, 2H perfluorooctyloxy)-5methoxy-benzyl alcohol (a yield of 70%).

ZH NMR (300 MHz, CDCl3) 7.74 (s, 1H, Ar-H), 7.22 (s, 1H, Ar H), 4.98 (s, 2H), 4.40-4.35 (t, 2H), 3.99 (s, 3H), 2.82-2.65 (m, 2H), 2.62 (br.s, lH); 13C NMR (75 MHz, CDCl3) 154.80, 146.79, 139.89, 133.75, 111.82, 110.56, 63.18, 56.90, 31.80, 31.54, 31.26.

The spectral data of 1H NMR, 13C NMR, MS, elemental analysis, and the like for the material (pale yellow solid) synthesized in reaction step (4) are as follows, and this material was identified as the compound 1 (a yield of 62%).

1H NMR (300 MHz, CDCl3) 7.80 (s, 1H, Ar-H), 7.23 (s, 1H, Ar H), 5.99 (s, 2H), 4.41-4.37 (t, 2H), 4.05 (s, 3H), 2.87 (s, 4H), 2.80-2.68 (m, 2H); 13C NMR (75 MHz, CDC13) 168.88, 155.07, 151.81, 147.36, 139.23, 126.89, 110.54, 109,49, 69.48, 62.09, 57.08, 31.76, 31.51, 31.23, 25.86; MS (FAB) 686 ([M]+, 8), 528 (100); HRSM (ES+) Calcd. For C2lHl5N2O9Fl3Na 709.0468, found 709.0473; Anal. Calcd. For C2lHl5N2O9Fl3:C 36.73%, H 2.20%, N 4.08%, found C 36.45%, H 2.35%, N 4.25%.

Example 2 A gold film was formed on a surface of a silicon substrate by sputtering.

Separately, a thiol solution was prepared by dissolving 1 mM of 11aminodecanethiol in ethanol. Next, the substrate provided with the gold film thereon was immersed into the thiol solution at room temperature for 12 hours. The substrate was then rinsed with ethanol and subsequently dried under nitrogen flow.

This resulted in a SAM film of 11-aminodecanethiol being formed on the gold surface of the substrate.

Subsequently, 150 mg of compound 1 as synthesized and purified in Example 1 was dissolved in 100 ml of anhydrous dichloromethane to form a solution at a concentration of approximately 2mM, and 2 ml of triethylamine was dissolved in the solution thus formed, thereby preparing a solution of compound 1. Next, the above-described substrate (hereinafter referred to as the "amino-surface substrate") having amino functional groups on the surface thereof was immersed in the solution thus prepared at room temperature for half a day, which allows the reaction between the succinic imide ester of compound 1 and the amino group of the amino-surface substrate to proceed. This reaction is illustrated in Figs. 2(1) and 2(2). After this reaction, the substrate was rinsed with dichloromethane, followed by drying by flowing nitrogen gas. A fluorinated chain modified SAM composed of molecules each having the structure shown in Fig. 2(2) was thus formed on the substrate surface.

The contact angle of the SAM (monomolecular film) surface thus formed was measured, and the advance angle (water) was approximately 90 to 100 . The variation in the measured angle is believed to be due to variations in the molecular coating state of the fluorinated chain modified SAM.

The fluorinated chain modified SAM surface was then irradiated with W having a wavelength of 365 nm through a photomask for varying time periods (1 minute, 5 minutes, 10 minutes, etc.). The W irradiation energy distribution used is illustrated in Fig. 3. The W irradiation energy was approximately 30 mW/cm2. The W irradiation resulted in the decomposition reaction shown in Figs. 2(2) and 2(3) to occur, and as a result, a SAM having amino groups represented by the structure shown in Fig. 2(3) was formed on the surface by decomposition.

After the W irradiation, the substrate surface was rinsed with ethanol, and the change in the surface contact angle (advance angle (water)) at four different locations where the SAM had been irradiated was measured. The results are shown in Table 1 below. The results show that the contact angle is reduced to approximately 50 when the SAM is irradiated for 1 to 5 minutes suggesting that the decomposition of the coupled SAM is substantially completed during this time period. Since the contact angle of the SAM surface when covered only with 11-aminodecanethiol was measured to be approximately 43 , it is believed that most of the fluorinated chains were removed by the irradiation.

In addition, the SAM was immersed in water after the irradiation and rinsing steps and was then pulled out therefrom. The surface of the SAM was then immediately observed. Water droplets were observed to remain where the SAM surface had been irradiated, that is the hydrophilic property was confirmed. On the other hand, the SAM surface repelled water at locations where it had been masked from the W radiation, that is the hydrophobic property was maintained.

Comparative Example

The silicon substrate coated with a solid film used as a starting substrate in Example 2 was immersed in a dichloromethane solution containing 1 mM of HS(CH2) 2 (CF2)'CF3. Then W irradiation was performed in a manner similar to that in Example 2, and the nettability of the surface was analyzed. As a result, the contact angle before W treatment was 110 with respect to water, and the contact angle after W irradiation for 5 minutes was approximately 109 , that is essentially unchanged.

Accordingly, it was confirmed that a SAM formed from HS(CH2) 2 (CF2)9 was hardly decomposed by W light (see the right-hand column of Table 1).

Table 1

Example 2 Comparative

Example

Compound 1 CF3(CF2)9(CH2)2SH l easured 1 2 3 4 C.A( ) C.A( ) C.A( ) C.A( ) C.A( ) W 1 min 67 67.8 66 69 109 W 5 min 53.1 53 52.6 53.1 109 W 10 min 50 49.5 49.7 50.9 1 108 W 20 min 50.5 50.1 50.8 51.4 104 W 30 min 48.5 49. 7 48.8 48.9 105 W 60 min 49.2 49.7 50.1 51.1 103 From the above description, it can be understood that the present invention provides a self-assembled monolayer (SAM) material which can form a monomolecular film on a substrate and which can be photopatterned by a relatively short exposure to low energy W irradiation. The SAM material provided can be applied to a variety of different types of substrates by means of suitable coupling compounds.

Prior to irradiation, the SAM material is hydrophobic and/or lipophobic. Irradiation however cleaves away the structural component responsible for this property leaving behind a functional group which is hydrophilic. Irradiation of the SAM material therefore substantially alters the surface property of the SAM-coated substrate.

Claims

CLAIMS: 1. A molecule comprising a structural component (A) which

decomposes when irradiated with W light having a wavelength in the range 254-400 nm, and a structural component (B) which is hydrophobic and/or lipophobic.
2. A molecule according to Claim 1, wherein the structural component (A) is an o-nitrobenzyl ester.
3. A molecule according to Claim 2, wherein the terminal group bonded to the benzyl group of the o-nitrobenzyl ester is a succinic imide.
4. A molecule according to any preceding claim, wherein the structural component (B) comprises a fluorinated chain.
5. A molecule according to Claim 4, wherein the fluorinated chain is saturated.
6. A molecule according to Claim 4 or Claim 5, wherein the fluorinated chain is branched and/or perfluorinated.
7. A molecule according to any preceding claim having the general formula (I): R1 R4R3 (I) R2\1f of l R.' O R5 NO2 wherein: R1 independently represents a hydrogen atom or -OR6, wherein R6 is a C1lO alkyl chain; R2 represents an N-hydroxy succinic imide group optionally substituted with a sulfonyl group; R3 represents -X2-(CH2)n-X1, wherein X2 represents -CH2or -O-, n is O or an integer of 1 to 10, and X represents -OZ, -Z or oz Y - (CH2)m - CH2 OZ wherein:

OZ

Y is -(CH2)- or -O-, Z is a C120 fluoroalkyl group and m is O or an integer of 1 to 10; R4 represents -NO2 or a hydrogen atom; and R5 is a hydrogen atom or a C1lO alkyl group.
8. A molecule according to Claim 7, wherein R is -OCH3.
9. A molecule according to Claim 7 or Claim 8, wherein Z is -(CH2) m (CF2) pF or a branched chain isomer thereof wherein m is as defined above and p is O or an integer of 1 to 9.
10. A molecule according to any of Claims 1-9, which is: O 0 { 5CF 3
11. A monomolecular film coated substrate, the film being formed from molecules comprising a structural component (B) which is hydrophobic and/or lipophobic, and a structural component (A) which decomposes when irradiated with W light S having a wavelength in the range 254-400 nm to cleave away a part of the molecule comprising the structural component (B) leaving a residual hydrophilic structural component (C).
12. A monomolecular film coated substrate according to Claim 11, wherein the structural component (A) is an o- nitrobenzyl ester.
13. A monomolecular film coated substrate according to Claim 11 or Claim 12, wherein the structural component (B) comprises a fluorinated chain.
14. A monomolecular film coated substrate according to Claim 13, wherein the fluorinated chain is saturated.
15. A monomolecular film coated substrate according to Claim 13 or Claim 14, wherein the fluorinated chain is branched and/or perfluorinated.
16. A monomolecular film coated substrate according to any 2s of Claims 11-15, wherein the hydrophilic structural component (C) includes an amine group or a hydroxyl group.
17. A monomolecular film coated substrate according to any of Claims 1116 obtainable by coating a substrate with a monomolecular film of a coupling compound (D) which comprises a hydrophilic moiety and subsequently reacting the hydrophilic moiety with a molecule according to any of Claims 1-11 to covalently bond the coupling compound (D) and molecule.
18. A monomolecular film coated substrate according to Claim 17, wherein the substrate is formed from a metal, a semiconductor or a plastics.
19. A monomolecular film coated substrate according to Claim 17 or Claim 18, wherein the hydrophilic moiety is an amine group or a hydroxyl group.
20. A monomolecular film coated substrate according to any of Claims 1115, wherein the molecules forming the film are as defined in any of Claims 1-10.
21. A monomolecular film coated substrate according to any of Claims 1115 or Claim 20, wherein the substrate has a hydrophilic surface prior to coating with the monomolecular film.
22. A method of photopatterning a monomolecular film coated substrate as defined in any of Claims 11-21 comprising the step of image-wise irradiating the monomolecular film coated substrate with W light having a wavelength in the range 254-400 nm through a patterned mask to cleave the coated molecules at the structural component (A) thus removing the structural component (B) from the coated film in the irradiated areas converting them from being hydrophobic and/or lipophobic to hydrophilic.
23. A molecule substantially as described herein with reference to Example 1.
24. A monomolecular film coated substrate substantially as described herein with reference to Example 2.
25. A method of photopatterning a monomolecular film coated substrate substantially as described herein with reference

to Example 2.