JPH05127386A - Photosensitive composition - Google Patents

Abstract

PURPOSE:To enhance the sensitivity and resolution of a photosensitive compsn. especially used in the case of exposure with KrF excimer laser beams. CONSTITUTION:This photosensitive compsn. contains a polymer obtd. by bonding a dissolution inhibiting group unstable to an acid to each hydroxyl group in the phenol skeleton of a hydrogenated alkali-soluble polymer, a compd. which generates the acid when irradiated with light and a hydrogenated alkali-soluble polymer and can form a resist film having high transparency to the wavelength region of deep UV or ionized radiation, especially KrF excimer laser beams. When the resist film is used, a resist pattern having high sensitivity and resolution can be produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive composition applicable to photoresists and the like.

[0002]

2. Description of the Related Art In the manufacturing process of semiconductor devices such as LSI,
The fine processing technology by photo etching is adopted. Specifically, this fine processing is performed according to the following process. That is, first, a photoresist film is formed on a substrate such as a silicon single crystal wafer by, for example, a spin coating method. Next, after exposing the resist film, a treatment such as development and rinsing is performed to form a resist pattern. Then, the exposed wafer surface is etched using the resist pattern as an etching resistant mask to open lines and windows having a fine width to form a desired pattern.

In the LSI manufacturing process as described above, a processing technique capable of forming a finer pattern is required as the LSI is highly integrated. In response to such a demand, attempts have been made to shorten the wavelength of the exposure light source. One of them is the KrF excimer laser (wavelength 248n
m) is used as a light source, and as the photoresist, a process of using a positive photoresist having a function of dissolving the exposed portion in a developing solution is adopted. However, in the case of a positive photoresist having a conventional composition, the absorption of KrF excimer laser light, for example, is too large in the exposed portion, so that the portion away from the surface of the resist film (for example, the interface region of the resist film that contacts the substrate)
It is not possible to sufficiently reach the laser light.
As a result, in the exposed portion of the photoresist film, the change due to exposure does not occur sufficiently over the entire film thickness, and the solubility in the developing solution in the film thickness direction becomes uneven. In particular, the solubility of the above-described portion of the resist film away from the surface is not sufficient, and the cross-sectional shape of the resist pattern formed after development becomes triangular. Therefore, when the resist pattern is used as an etching-resistant mask for a substrate or the like, the desired fine etching pattern cannot be transferred to the substrate or the like, which is a problem.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its object is to expose a substrate or the like as a photoresist film at a short wavelength by a KrF excimer laser or the like. At this time, since the light transmittance is high, it is possible to sufficiently reach the portion over the entire film thickness, that is, the portion away from the film surface, and it is possible to form a resist pattern having a good cross-sectional shape after the development processing. It is to provide a photosensitive composition.

[0005]

The photosensitive composition of the present invention has a hydroxyl group in the phenol skeleton of a hydrogenated alkali-soluble polymer having a phenol skeleton, which has an acid-labile dissolution inhibiting group. It is characterized by containing a polymer formed by bonding and a compound capable of generating an acid upon irradiation with light. Hereinafter, the photosensitive composition of the present invention will be described in detail.

The above-mentioned polymer corresponding to the main component of the photosensitive composition of the present invention is prepared by introducing a specific protecting group into an alkali-soluble polymer having a phenol skeleton, whereby a hydroxyl group in the phenol skeleton, that is, a phenolic structure is obtained. It blocks hydroxyl groups and suppresses the alkali solubility inherent in the alkali-soluble polymer.

Examples of the alkali-soluble polymer having a phenol skeleton include phenol novolac resin, cresol novolac resin, xylenol novolac resin, vinyl phenol resin, isopropenyl phenol resin, vinyl phenol and acrylic acid, methacrylic acid derivative, acrylonitrile, A copolymer with a styrene derivative and the like, a copolymer with isopropenylphenol and an acrylic acid, a methacrylic acid derivative, acrylonitrile, a styrene derivative and the like can be used. More specifically, poly (p-
Vinylphenol), a copolymer of p-isopropenylphenol and acrylonitrile (copolymerization ratio 1: 1), a copolymer of p-isopropenylphenol and styrene (copolymerization ratio 1: 1), p-vinylphenol And a copolymer of methyl methacrylate (copolymerization ratio 1: 1), a copolymer of p-vinylphenol and styrene (copolymerization ratio 1: 1), and the like.

In the present invention, when a photoresist film is formed using the finally obtained photosensitive composition,
For the purpose of improving the light transmittance, the above-mentioned alkali-soluble polymer having a phenol skeleton is hydrogenated. The hydrogenation reaction for the alkali-soluble polymer can be performed according to a known method. Specifically, as disclosed in JP-A-1-103604,
Examples thereof include a method in which an alkali-soluble polymer is dissolved in a solvent and then contacted with hydrogen in the presence of a Group VIII metal catalyst.

A solubility-inhibiting group unstable to an acid binding to a hydroxyl group in the phenol skeleton of the alkali-soluble polymer having a phenol skeleton and further hydrogenated, that is, a phenolic hydroxyl group, is formed. Examples of the dissolution inhibiting group to be blocked include various known protecting groups. Specifically, it is not particularly limited as long as it is an acid-labile group, but it is possible to use tert-butyl esters of carboxylic acids such as those disclosed in JP-A-2-27660, tertiary-tertiary esters such as tert-butyl carbonate. Protecting group having carbon, JP-A-63-13943
As disclosed in JP-A No. 60-52845, cyclohexyl, sec-butyl group, isopropyl group and the like having a secondary carbon, trialkyl group, phenylsilyl group, etc. Examples thereof include acid-labile protecting groups such as tetrahydropyranyl group and methylmethoxy group as disclosed in JP-A 2-19847.

Of these acid-labile dissolution inhibiting groups,
The introduction rate of the repeating unit of the alkali-soluble polymer having a phenol skeleton is 5 to 100%, preferably
It is in the range of 10 to 50%. If the introduction rate is less than 5%, a sufficient alkali dissolution inhibiting effect on the alkali-soluble polymer cannot be obtained. On the other hand, when the introduction rate is high, depending on the type of the protective group to be introduced, when the resulting photosensitive composition is used as a photoresist, development with an alkaline aqueous solution may be impossible.

The polymer of which the alkali solubility is suppressed contained in the photosensitive composition of the present invention is usually a hydrogenated alkali-soluble polymer having a phenol skeleton as described above, which is added to an acid. It can be obtained by reacting a compound or the like that can give an unstable dissolution inhibiting group. In addition to this, a monomer having a phenol skeleton is previously introduced with an acid-labile dissolution-inhibiting group similar to the above to block the phenolic hydroxyl group of the monomer, and then the monomer is polymerized and further hydrogenated. It is also possible to obtain a polymer in which the alkali solubility is suppressed.

On the other hand, in the photosensitive composition of the present invention, a compound corresponding to a photosensitizer which generates an acid upon irradiation with light is
Various known compounds and mixtures thereof can be used. For example, CF ₃ SO ₃ ^- , P-CH ₃ PhSO ₃ ^- ,
p-NO ₂ PhSO ₃ ^- A diazonium salt, a phosphonium salt, a sulfonium salt, an iodonium salt, an organic halogen compound, orthoquinone diazide sulfonic acid ester, etc., which have the above as a counter anion can be used. Further, an organic halogen compound known as a photoinitiator that forms a free radical is also a compound that forms a hydrohalic acid, and can be used as a compound that generates an acid upon irradiation with light in the present invention.

Specific examples of the above-mentioned compound which generates an acid upon irradiation with light include di (paratertiarybutylphenyl) iodonium trifluoromethanesulfonate, benzointosylate, orthonitrobenzene paratoluenesulfonate, triphenylsulfonium trifluoromethanesulfonate, and triphenylsulfonium trifluoromethanesulfonate. (Tert-butylphenyl) sulfonium trifluoromethanesulfonate, benzenediazonium paratoluenesulfonate, tris-dibromomethyl-s-triazine, o-naphthoquinonediazide-4-
Examples thereof include sulfonic acid ester.

In the photosensitive composition of the present invention, the compounding amount of the compound capable of generating an acid upon irradiation with light is preferably about 0.01 to about 20% by weight based on the total weight of the solid component of the photosensitive composition. And more preferably 0.1 to 10% by weight. If the blending amount is less than 0.01% by weight, the effect of adding the compound cannot be obtained, while if it exceeds 10% by weight, a film is formed using the obtained photosensitive composition,
The coating property may deteriorate.

In the photosensitive composition of the present invention, the polymer whose alkali solubility is suppressed has an acid-labile dissolution-inhibiting group introduced therein. When a resist film is formed, the heat resistance of the film may decrease. In order to solve this problem, the photosensitive composition of the present invention may further contain an alkali-soluble polymer having a phenol skeleton in addition to the above two components.
The alkali-soluble polymer having a phenol skeleton may be any one that has sufficient heat resistance when formed into a film and is compatible with other components in the photosensitive composition. For example, alkali-soluble polymers having various phenol skeletons as described above can be used. The alkali-soluble polymer added here is also hydrogenated in the same manner as above for the purpose of improving the light transmittance of the photoresist film formed by using the obtained photosensitive composition. Further, by adding the alkali-soluble polymer having a phenol skeleton, it is possible to adjust the introduction rate of the acid-labile dissolution inhibiting group into the alkali-soluble polymer to an optimum condition.

When the alkali-soluble polymer is contained in the photosensitive composition of the present invention as described above, the blending amount thereof is 0 to 900 with respect to 100 parts by weight of the alkali-solubilized polymer. Parts by weight, more preferably 0-400
The range is parts by weight. If this blending amount exceeds 900 parts by weight, the contrast of exposed and unexposed areas of the resulting photosensitive composition may not be sufficiently obtained.

In addition to the above components, the photosensitive composition of the present invention may further contain, for example, an alkali-soluble resin, a surfactant as a coating film modifier, or a dye as an antireflection film, if necessary. You may mix.

The photosensitive composition of the present invention can be preferably used especially as a positive photoresist because of the function of the compound that generates an acid upon irradiation with light. That is, in the photosensitive composition of the present invention, in the unexposed state, the acid-labile dissolution inhibiting group functions as a hydrophobic protecting group as described above, and alkali solubility is suppressed. On the other hand, at the time of exposure, an acid is generated from the compound that generates an acid by the light irradiation in the exposed portion, and this acid decomposes the dissolution inhibiting group that has blocked the phenolic hydroxyl group of the polymer. Since the dissolution inhibiting group changes from a hydrophobic protecting group to a hydrophilic group such as a hydroxyl group or a carboxylic acid group, the alkali solubility of the polymer whose alkali solubility is suppressed in the exposed portion of the photosensitive composition The solubility in the developer is increased. Thereafter, the photosensitive composition is subjected to a developing treatment with an alkali developing solution having an appropriate concentration, whereby only the exposed portion of the photosensitive composition is dissolved and removed to form a positive resist pattern.

In the photosensitive composition of the present invention, when an appropriate organic developing solution is used in the developing step after exposure, a hydrophobic unexposed portion is dissolved, so that a negative pattern is formed. You can also do it. Next, a more specific pattern forming process when the photosensitive composition of the present invention is used as a photoresist will be described.

First, the photosensitive composition of the present invention is dissolved in an organic solvent, this solution is applied onto a substrate by a spin coating method or a dipping method, and dried by heating to form a resist film. The heating conditions are set to 60 ° C to 140 ° C. This heating condition
If the temperature is lower than 60 ° C, the resist film will be insufficiently dried.
If the temperature exceeds 0 ° C, the performance of the resist may deteriorate due to the modification of each component in the composition. Examples of the substrate used here include a silicon wafer, a silicon wafer having a stepped surface on which various insulating films, electrodes, wirings, etc. are formed, a blank mask, and the like. Examples of the organic solvent that dissolves the photosensitive composition include, for example, ketone solvents such as cyclohexanone, acetone, methyl ethyl ketone, and methyl isobutyl ketone, methyl cellosolve, methyl cellosolve acetate,
Cellosolve solvents such as ethyl cellosolve acetate, butyl cellosolve acetate, ethyl acetate, butyl acetate,
Examples thereof include ester solvents such as isoamyl acetate. These organic solvents can be used alone or in the form of a mixture.

Then, deep UV irradiation (exposure) is performed on the resist film through a mask having a desired pattern using a mercury lamp KrF excimer laser, an ArF excimer laser, or the like as an exposure source. Then, the resist film after pattern exposure is heat-treated. This heating condition varies depending on the kind of the compound that generates an acid upon irradiation with light, but is carried out in the range of 80 to 140 ° C. for 30 to 600 seconds. If the temperature is less than 80 ° C, the exposed part of the resist film
The decomposition reaction of the polymer dissolution inhibiting group by the generated acid does not proceed sufficiently. On the other hand, when the temperature exceeds 140 ° C., thermal decomposition proceeds in the unexposed portion of the resist film, and the contrast of the finally formed resist pattern decreases. Incidentally, the exposure of the resist film by the photosensitive composition of the present invention,
In addition to ultraviolet rays such as deep UV, X-rays, electron beams, ion beams and the like can be used.

Next, the resist film is developed using an alkaline aqueous solution. By this treatment, the exposed portion of the resist film is dissolved and removed in an alkaline solution, and a desired resist pattern is formed. The alkaline aqueous solution used here may be any one as long as it has a property that the exposed portion of the resist film is rapidly dissolved and the dissolution rate in other exposed portions is extremely low. Specific examples thereof include tetraalkylammonium-based aqueous solutions such as tetramethylammonium hydroxide aqueous solutions and inorganic alkaline aqueous solutions such as potassium hydroxide and sodium hydroxide. These alkaline aqueous solutions are usually used at a concentration of 15% by weight or less. Further, as the developing means,
For example, a dipping method, a spray method or the like can be adopted.
Further, after development, the developing solution is washed off with water.

The substrate (wafer) is etched using the resist pattern formed as described above as a mask. As this etching means, a wet etching method or a dry etching method is adopted. In particular, the dry etching method is preferable when forming a fine pattern of 3 μm or less. As the wet etching agent, a hydrofluoric acid aqueous solution, an ammonium fluoride aqueous solution or the like is used when the silicon oxide film is an etching target, and a phosphoric acid aqueous solution, an acetic acid aqueous solution, a nitric acid aqueous solution or the like is used when the aluminum is an etching target, When the chromium-based film is to be etched, an aqueous solution of cerium ammonium nitrate may be used.
Examples of the dry etching gas include CF ₄ and C ₂ F
₆ , CCl ₄ , BCl ₃ , Cl ₂ , HCl, etc. may be used. These gases are used in combination as required. Regarding the conditions of the etching, based on the combination of the type of substrate on which the fine pattern is formed and the photosensitive composition, the concentration of the wet etching agent or the concentration of the dry etching gas in the reaction tank, the reaction temperature, the reaction time, etc. , Respectively, but the method is not particularly limited.

After the etching as described above, the resist pattern of the photosensitive composition remaining on the substrate, and the flattening layer remaining when the multilayer resist technique is adopted are removed by, for example, a release agent (J -100: manufactured by Nagase Kasei Co., Ltd.), and removed by oxygen gas plasma or the like.

In addition to the above steps, other steps can be adopted as necessary. For example, the adhesion between the resist film formed by the photosensitive composition of the present invention and the substrate,
Further, in order to improve the adhesion between the resist film and the flattening layer, between the flattening layer and the substrate when the multilayer resist technique is adopted, each layer is pretreated. In addition, baking may be performed before and after the development process, and ultraviolet ray re-irradiation may be performed before the dry etching.

[0026]

In the photosensitive composition of the present invention, a polymer whose alkali solubility is suppressed is added to an alkali-soluble polymer to be added, and hydrogenation of each phenyl ring proceeds. There is. Therefore, the absorptivity of light with a short wavelength such as KrF excimer laser light is reduced, and the light transmissivity when formed into a film is significantly improved. Further, the alkali-solubilized polymer is a polymer in which an acid-labile dissolution-inhibiting group is introduced on the basis of a hydrogenated alkali-soluble polymer. Is further enhanced, and the alkali solubility of the resist solution can be easily controlled. On the other hand, the compound that generates an acid upon irradiation with light, which is a photosensitizer, has extremely high sensitivity to KrF excimer laser light and the like.

Specifically, the photosensitive composition of the present invention has a thickness
When a resist film is formed on the substrate at 1.0 μm,
The resist film is made of KrF excimer laser light (wavelength 248n
m) is composed of a hydrogenated polymer having an alkali solubility of 50% or more and an alkali-soluble polymer and a photosensitizer having high sensitivity to light of the above wavelength. Will be

Therefore, when a resist film is formed on a substrate using the photosensitive composition of the present invention and exposed to deep UV such as KrF excimer laser, the exposed surface of the resist film has a film surface. The light can reach a portion away from the film, and the change due to exposure is sufficiently generated over the entire film thickness, so that the solubility in the alkali developing solution is uniformly expressed. On the other hand, in the unexposed portion of the resist film, the ability of the dissolution inhibiting group in the polymer is high as described above,
Solubility in alkaline developers is strongly suppressed.
As a result, by the development process after exposure, a high-resolution resist pattern having a cross-sectional shape in which the widths of the top surface and the bottom surface are substantially uniform is formed. Furthermore, a desired fine resist pattern can be faithfully transferred to the substrate or the like by etching the substrate or the like using the resist pattern as an etching mask. That is, according to the photosensitive composition of the present invention, it is possible to form a pattern with high resolution by hydrogenating the polymer and suppressing the alkali solubility by the dissolution inhibiting group.

[0029]

EXAMPLES Examples of the present invention will be described in detail below.
Note that these examples are described for the purpose of facilitating the understanding of the present invention, and do not limit the present invention.

Example 1 A 500 ml four-necked flask purged with nitrogen was charged with a solution prepared by dissolving 100 g (0.835 mol) of hydrogenated poly (p-vinylphenol) in 250 g of tetrahydrofuran.
28.1 g of potassium tert-butoxide (0.251 mo
l) and then treated with 50 ml of tetrahydrofuran in di-tert-
A solution in which 54.6 g (0.251 mol) of butyl-di-carbonate was dissolved was added and reacted at room temperature for 3 hours. After filtration, the reaction solution was added dropwise to a large amount of water to obtain a precipitate. The precipitate was dissolved in ethanol and added dropwise to a large amount of a 5% acetic acid solution for further purification, and then sufficiently dried in vacuum at 50 ° C. About the modified polyvinylphenol obtained ¹ When analyzed by 1 H-NMR spectrum, 60% of the repeating units of the polymer were protected by acid labile groups. Wavelength at 1 μm film thickness of this polymer
The transmittance of light at 248 nm was measured by spin-coating the polymer ethyl cellosolve acetate solution onto a quartz wafer at 90 ° C.
It was 66% when the sample which dried the solvent for a minute was measured by the transmission method using an ultraviolet spectroscope.

Next, 30 g of the polymer synthesized as described above.
And 70 g of poly (p-vinylphenol) and 1 g of diphenyliodonium trifluoromethanesulfonate were dissolved in 300 g of ethyl cellosolve acetate, and this solution was filtered using a fluororesin membrane filter having a pore size of 0.2 μm to obtain the present invention. A solution containing the photosensitive composition of 1. was prepared.

Then, the above solution is applied onto a silicon wafer and dried on a hot plate at 90 ° C. for 5 minutes to obtain a thickness.
A resist film of 1.0 μm was formed. Then, the resist film was exposed through a mask having a predetermined pattern to a reduction projection exposure machine using KrF excimer laser light (248 nm) (40 mJ / cm ² ) Was done. Furthermore, after baking the exposed resist film on a hot plate at 120 ° C for 3 minutes,
A resist pattern was obtained by immersing in a 2.38 wt% tetramethylammonium hydroxide aqueous solution for 1 minute for development, and further washing with water. When the cross section of this pattern was observed by an electron microscope, a highly accurate resist pattern having a line width of 0.25 μm and a rectangular cross section was formed.

Example 2 A nitrogen-purged 500 ml four-necked flask was charged with a solution of 100 g (0.835 mol) of hydrogenated poly (p-vinylphenol) in 250 g of tetrahydrofuran.
28.1 g of potassium tert-butoxide (0.251 mo
l), di-tert-
A solution in which 61.7 g (0.251 mol) of pentyl-di-carbonate was dissolved was added, and the mixture was reacted at room temperature for 3 hours. afterwards,
A product (a polymer with suppressed alkali solubility) was obtained by the same operation as in Example 1. Example 1 for this polymer
When analyzed in the same manner as above, the introduction rate of the acid-labile group was 55%, and the transmittance of light having a wavelength of 248 nm at a film thickness of 1 μm was 67%.

Next, 50 g of the polymer synthesized as described above.
50 g of poly (p-vinylphenol), 1 g of triphenylsulfonium trifluoromethanesulfonate,
Using a resist solution prepared with 300 g of ethyl cellosolve acetate, patterning was performed by the same method and conditions as in Example 1, and the cross section of the obtained pattern was observed. As a result, a highly accurate resist pattern having a line width of 0.25 μm and a rectangular cross section was formed.

Example 3 A nitrogen-purged 500 ml four-necked flask was charged with a solution of 100 g (0.748 mol) of hydrogenated polyisopropenylphenol in 250 g of tetrahydrofuran. This solution was added to potassium tert-butoxide 41.9 g (0.37
4 mol) and then treated with 50 ml of tetrahydrofuran.
A solution in which 91.9 g (0.374 mol) of t-pentyl-di-carbonate was dissolved was added, and the mixture was reacted at room temperature for 3 hours. Then, a product (a polymer in which alkali solubility was suppressed) was obtained by the same operation as in Example 1. When this polymer was analyzed in the same manner as in Example 1, the introduction rate of the acid-labile group was 90%, and the transmittance of light having a wavelength of 248 nm at a film thickness of 1 μm was 66%. there were.

Next, 30 g of the polymer synthesized as described above.
70g of poly (p-vinylphenol), 1g of triphenylsulfonium trifluoromethanesulfonate,
Using a resist solution prepared with 300 g of ethyl cellosolve acetate, patterning was performed by the same method and conditions as in Example 1, and the cross section of the obtained pattern was observed. As a result, a highly accurate resist pattern having a line width of 0.35 μm and a rectangular cross section was formed.

Further, the heat resistance of this photosensitive composition was evaluated as follows. That is, the resist pattern sample formed on the silicon wafer as described above was first baked on a hot plate at 130 ° C. for 5 minutes. Subsequently, several samples were heated at different temperatures for 5 minutes, and then the cross section of the resist pattern in each sample was observed with a scanning electron microscope. As a result, no change was observed in the cross-sectional shape of the pattern for the sample heated at 140 ° C or lower.

Example 4 A 500 ml four-necked flask purged with nitrogen was charged with a solution prepared by dissolving 100 g (0.748 mol) of hydrogenated polyisopropenylphenol in 250 g of tetrahydrofuran. 8.38 g (0.07 g) of potassium tert-butoxide was added to this solution.
(48 mol) and then treated with 50 ml of tetrahydrofuran.
A solution in which 18.4 g (0.0748 mol) of t-pentyl-di-carbonate was dissolved was added, and the mixture was reacted at room temperature for 3 hours. Then, a product (a polymer in which alkali solubility was suppressed) was obtained by the same operation as in Example 1. When this polymer was analyzed in the same manner as in Example 1, the introduction rate of the acid labile group was 10%, and the transmittance of light having a wavelength of 248 nm at a film thickness of 1 μm was 70%. It was

Next, the polymer 100 synthesized as described above.
g, triphenylsulfonium trifluoromethanesulfonate 1 g, ethyl cellosolve acetate 300 g
Using the resist solution prepared by the above method, patterning was performed under the same method and conditions as in Example 1, and the cross section of the obtained pattern was observed. As a result, the line width is 0.35μ
m, a high-precision resist pattern having a rectangular cross section was formed.

Further, the heat resistance of this photosensitive composition was evaluated in the same manner as in Example 3 and under the same conditions.
No change was observed in the cross-sectional shape of the pattern for the sample heated at 50 ° C or lower.

Example 5 A nitrogen-purged 500 ml four-necked flask was charged with a solution of 100 g (0.748 mol) of hydrogenated polyisopropenylphenol dissolved in 250 g of tetrahydrofuran. 8.38 g (0.07 g) of potassium tert-butoxide was added to this solution.
(48 mol) and then di-se in 50 ml of tetrahydrofuran.
A solution in which 18.4 g (0.0748 mol) of c-pentyl-di-carbonate was dissolved was added, and the mixture was reacted at room temperature for 3 hours. Then, a product (a polymer in which alkali solubility was suppressed) was obtained by the same operation as in Example 1. When this polymer was analyzed in the same manner as in Example 1, the introduction rate of the acid-labile group was 10%, and the transmittance of light having a wavelength of 248 nm at a film thickness of 1 μm was 69%. there were.

Next, the polymer 100 synthesized as described above was used.
g, triphenylsulfonium trifluoromethanesulfonate 1 g, ethyl cellosolve acetate 300 g
Using the resist solution prepared by the above method, patterning was performed under the same method and conditions as in Example 1, and the cross section of the obtained pattern was observed. As a result, the line width is 0.3μ
m, a high-precision resist pattern having a rectangular cross section was formed.

Example 6 In a 500 ml four-necked flask purged with nitrogen, 17.6 g (0.106 mol) of potassium iodide and 36.5 g (0.26 g of potassium carbonate) were added.
4 mol), and a solution of 100 g (0.748 mol) of hydrogenated polyisopropenylphenol in 250 g of acetone and 50.5 g of tert-butyl bromoacetate (0.
259 mol) was added directly and the mixture was refluxed for 7 hours. Then, Example 1
A product (a polymer whose alkali solubility was suppressed) was obtained by the same operation as in (1). When this polymer was analyzed in the same manner as in Example 1, the rate of introduction of acid-labile groups was 40%.
And the transmittance of light with a wavelength of 248 nm at a film thickness of 1 μm is
It was 67%.

Next, 60 g of the polymer synthesized as described above.
And 40 g of polyisopropenylphenol and 1 g of triphenylsulfonium trifluoromethanesulfonate
And a cellulosic acetate of 300 g were used to perform patterning under the same method and conditions as in Example 1, and the cross section of the obtained pattern was observed. As a result, a highly accurate resist pattern having a line width of 0.25 μm and a rectangular cross section was formed.

Example 7 In a 500 ml four-necked flask purged with nitrogen, 17.6 g (0.106 mol) of potassium iodide and 36.5 g of potassium carbonate (0.
264 mol), and then a solution of 100 g (0.748 mol) of hydrogenated polyisopropenylphenol in 250 g of acetone and 54.1 g (0.259 mol) of tert-butyl β-bromopropionate were directly added, Reflux for hours.
Then, a product (a polymer in which alkali solubility was suppressed) was obtained by the same operation as in Example 1. For this polymer,
When analyzed in the same manner as in Example 1, the introduction rate of the acid-labile group was 36%, and the wavelength 248 at a film thickness of 1 μm was obtained.
The light transmittance of nm was 68%.

Next, 70 g of the polymer synthesized as described above.
, Polyisopropenylphenol 30g, triphenylsulfonium trifluoromethanesulfonate 1g
And a cellulosic acetate of 300 g were used to perform patterning under the same method and conditions as in Example 1, and the cross section of the obtained pattern was observed. As a result, a highly accurate resist pattern having a line width of 0.25 μm and a rectangular cross section was formed.

Example 8 In a 500 ml four-necked flask purged with nitrogen, 17.6 g (0.106 mol) of potassium iodide and 36.5 g (0.26 g of potassium carbonate) were added.
4 mol), and then a solution of 100 g (0.748 mol) of hydrogenated polyisopropenylphenol in 250 g of acetone, and 54.1 g (0.259 mol) of tert-butyl γ-bromopropionate were directly added. Reflux for hours. Then, a product (a polymer in which alkali solubility was suppressed) was obtained by the same operation as in Example 1. When this polymer was analyzed in the same manner as in Example 1, the introduction rate of the acid-labile group was 38%, and the wavelength was 248 nm at a film thickness of 1 μm.
The light transmittance was 70%.

Next, 80 g of the polymer synthesized as described above.
And 20 g of poly (p-vinylphenol), 1 g of triphenylsulfonium trifluoromethanesulfonate,
Using a resist solution prepared with 300 g of ethyl cellosolve acetate, patterning was performed by the same method and conditions as in Example 1, and the cross section of the obtained pattern was observed. As a result, a highly accurate resist pattern having a line width of 0.25 μm and a rectangular cross section was formed.

Example 9 A 500 ml four-necked flask purged with nitrogen was charged with 17.6 g (0.106 mol) of potassium iodide and 36.5 g (0.26 g of potassium carbonate).
4 mol), and then a solution of 100 g (0.835 mol) of hydrogenated poly (p-vinylphenol) in 250 g of acetone and tert-butyl bromoacetate 50.5 g (0.25
(9 mol) was added directly and the mixture was refluxed for 7 hours. Then, Example 1
A product (a polymer whose alkali solubility was suppressed) was obtained by the same operation as in (1). When this polymer was analyzed in the same manner as in Example 1, the rate of introduction of acid-labile groups was 31%.
And the transmittance of light with a wavelength of 248 nm at a film thickness of 1 μm is
It was 71%.

Next, 85 g of the polymer synthesized as described above
And 15 g of poly (p-vinylphenol), 1 g of triphenylsulfonium trifluoromethanesulfonate,
Using a resist solution prepared with 300 g of ethyl cellosolve acetate, patterning was performed by the same method and conditions as in Example 1, and the cross section of the obtained pattern was observed. As a result, a highly accurate resist pattern having a line width of 0.25 μm and a rectangular cross section was formed.

Example 10 In a nitrogen-substituted 1000 ml four-necked flask, 34.6 g (0.208 mol) of potassium iodide and 71.4 g (0.51 of potassium carbonate) were added.
8 mol), and then a solution of 200 g (1.67 mol) of hydrogenated poly (p-vinylphenol) in 500 g of acetone, and tert-butyl bromoacetate 101.0 g (0.51
(8 mol) was added directly and the mixture was refluxed for 7 hours. Then, Example 1
A product (a polymer whose alkali solubility was suppressed) was obtained by the same operation as in (1). When this polymer was analyzed in the same manner as in Example 1, the rate of introduction of acid-labile groups was 33%.
And the transmittance of light with a wavelength of 248 nm at a film thickness of 1 μm is
It was 73%.

Next, 60 g of the polymer synthesized as described above.
And the same method and conditions as in Example 1 using a resist solution prepared with 40 g of poly (p-vinylphenol), 3 g of o-naphthoquinonediazide-4-sulfonic acid ester and 300 g of ethyl cellosolve acetate. The patterning was carried out by using the above method, and the cross section of the obtained pattern was observed. As a result, a highly accurate resist pattern having a line width of 0.25 μm and a rectangular cross section was formed.

Example 11 In a 500 ml four-necked flask purged with nitrogen, 10.3 g (0.062 mol) of potassium iodide and 21.4 g (0.15 g of potassium carbonate) were added.
5 mol), and 250 g of acetone in which 100 g (0.835 mol) of hydrogenated poly (p-vinylphenol) was dissolved, and tert-butyl bromoacetate 30.3 g (0.15
(5 mol) was added directly and the mixture was refluxed for 7 hours. Then, Example 1
A product (a polymer whose alkali solubility was suppressed) was obtained by the same operation as in (1). When this polymer was analyzed in the same manner as in Example 1, the rate of introduction of acid-labile groups was 20%.
And the transmittance of light with a wavelength of 248 nm at a film thickness of 1 μm is
It was 70%.

Next, the polymer 100 synthesized as described above was used.
g and o-naphthoquinonediazide-4-sulfonic acid ester
Using a resist solution prepared from 5 g of ethyl cellosolve acetate and 300 g of ethyl cellosolve acetate, patterning was performed by the same method and conditions as in Example 1, and the cross section of the obtained pattern was observed. As a result, a highly accurate resist pattern having a line width of 0.25 μm and a rectangular cross section was formed.

Example 12 In a nitrogen-substituted 200 ml four-necked flask, 17.3 g (0.104 mol) of potassium iodide and 35.7 g (0.25
9 mol), and a solution of 50 g (0.417 mol) of hydrogenated poly (p-vinylphenol) in 250 g of acetone, and 46.9 g of isopropyl bromoacetate (0.259 m
ol) was added directly and the mixture was refluxed for 7 hours. Then, a product (a polymer in which alkali solubility was suppressed) was obtained by the same operation as in Example 1. When this polymer was analyzed in the same manner as in Example 1, the introduction rate of the acid-labile group was 60%, and the transmittance of light having a wavelength of 248 nm at a film thickness of 1 μm was 68%.
%Met.

Next, 80 g of the polymer synthesized as described above.
And the same method and conditions as in Example 1 using a resist solution prepared with 20 g of poly (p-vinylphenol), 10 g of o-naphthoquinonediazide-4-sulfonic acid ester, and 300 g of ethyl cellosolve acetate. The patterning was carried out by using the above method, and the cross section of the obtained pattern was observed. As a result, a highly accurate resist pattern having a line width of 0.25 μm and a rectangular cross section was formed.

Example 13 17.6 g (0.106 mol) of potassium iodide and 36.5 g (0.26 g of potassium carbonate) were placed in a 500 ml four-neck flask purged with nitrogen.
4 mol), and then a solution of 100 g (0.835 mol) of hydrogenated poly (p-vinylphenol) in 250 g of acetone and 46.9 g (0.25
(9 mol) was added directly and the mixture was refluxed for 7 hours. Then, Example 1
A product (a polymer whose alkali solubility was suppressed) was obtained by the same operation as in (1). When this polymer was analyzed in the same manner as in Example 1, the introduction rate of the acid-labile group was 33%.
And the transmittance of light with a wavelength of 248 nm at a film thickness of 1 μm is
It was 70%.

Next, 80 g of the polymer synthesized as described above.
And the same method and conditions as in Example 1 using a resist solution prepared with 20 g of poly (p-vinylphenol), 10 g of o-naphthoquinonediazide-4-sulfonic acid ester, and 300 g of ethyl cellosolve acetate. The patterning was carried out by using the above method, and the cross section of the obtained pattern was observed. As a result, a highly accurate resist pattern having a line width of 0.25 μm and a rectangular cross section was formed.

Example 14 A solution prepared by dissolving 72 g (0.600 mol) of hydrogenated poly (p-vinylphenol) in 500 g of tetrahydrofuran in a 1000 ml four-necked flask purged with nitrogen, 2,3-dihydro-4H. -Pyran (12.6 g, 0.150 mol) and hydrochloric acid (1 ml) were directly added, and the mixture was reacted for 7 hours under ice cooling. Then, Example 1
A product (a polymer whose alkali solubility was suppressed) was obtained by the same operation as in (1). When this polymer was analyzed in the same manner as in Example 1, the rate of introduction of acid-labile groups was 30%.
And the transmittance of light with a wavelength of 248 nm at a film thickness of 1 μm is
It was 71%.

Next, 50 g of the polymer synthesized as described above.
And o-naphthoquinonediazide-4-sulfonic acid ester 5
g and 150 g of ethyl cellosolve acetate were used to perform patterning by the same method and conditions as in Example 1, and the cross section of the obtained pattern was observed. As a result, a highly accurate resist pattern having a line width of 0.35 μm and a rectangular cross section was formed.

Example 15 A 500 ml four-necked flask purged with nitrogen was charged with pyridine 2
72g of poly (p-vinylphenol) hydrogenated to 50g
(0.600mol) dissolved solution and tert-butyldimethylchlorosilane 22.6g (0.150mol) were added directly, 3
The reaction was carried out at room temperature for an hour. Then, a product (a polymer in which alkali solubility was suppressed) was obtained by the same operation as in Example 1. When this polymer was analyzed in the same manner as in Example 1, the introduction rate of acid labile groups was 30%, and the transmittance of light having a wavelength of 248 nm at a film thickness of 1 μm was 70%. there were.

Next, 50 g of the polymer synthesized as described above.
And o-naphthoquinonediazide-4-sulfonic acid ester 5
g and 150 g of ethyl cellosolve acetate were used to perform patterning by the same method and conditions as in Example 1, and the cross section of the obtained pattern was observed. As a result, a highly accurate resist pattern having a line width of 0.35 μm and a rectangular cross section was formed.

Comparative Example 1 A 500 ml four-necked flask purged with nitrogen was charged with a solution of 250 g of tetrahydrofuran in which 100 g (0.835 mol) of poly (p-vinylphenol) not hydrogenated was dissolved. It was 28.1 g (0.2%) of potassium tert-butoxide was added to this solution.
(51 mol), di-t was added to 50 ml of tetrahydrofuran.
A solution in which 54.6 g (0.251 mol) of ert-butyl-di-carbonate was dissolved was added, and the mixture was reacted at room temperature for 3 hours. afterwards,
A product (a polymer with suppressed alkali solubility) was obtained by the same operation as in Example 1. Example 1 for this polymer
When analyzed in the same manner as in 1., the introduction rate of acid labile groups was 60%, and the transmittance of light having a wavelength of 248 nm at a film thickness of 1 μm was 25%.

Next, 30 g of the polymer synthesized as described above.
And using a resist solution prepared from 70 g of poly (p-vinylphenol), 1 g of diphenyliodonium trifluoromethanesulfonate, and 300 g of ethyl cellosolve acetate, patterning was carried out by the same method and conditions as in Example 1, The cross section of the obtained pattern was observed. As a result, a resist pattern having a line width of 0.40 μm and a trapezoidal cross section was formed.

Comparative Example 2 A 500 ml four-necked flask purged with nitrogen was charged with a solution of 250 g of tetrahydrofuran in which 100 g (0.748 mol) of polyisopropenylphenol which had not been hydrogenated was dissolved. 8.38 g of potassium tert-butoxide was added to this solution.
(0.0748 mol) and then treated with 50 ml of tetrahydrofuran, 18.4 g of di-tert-pentyl-di-carbonate (0.0748 mol)
The solution in which l) was dissolved was added and reacted at room temperature for 3 hours. Then, a product (a polymer in which alkali solubility was suppressed) was obtained by the same operation as in Example 1. When this polymer was analyzed in the same manner as in Example 1, the rate of introduction of acid-labile groups was 10%, and the wavelength at a film thickness of 1 μm was measured.
The transmittance of light at 248 nm was 23%.

Next, the polymer 100 synthesized as described above.
g, triphenylsulfonium trifluoromethanesulfonate 1 g, ethyl cellosolve acetate 300 g
Using the resist solution prepared by the above method, patterning was performed under the same method and conditions as in Example 1, and the cross section of the obtained pattern was observed. As a result, the line width is 0.45μ
m, a resist pattern having a trapezoidal cross section was formed.

[0067]

As described in detail above, according to the present invention, when a substrate or the like is coated with a photoresist film, a deep
It has high sensitivity to UV and ionizing radiation, especially KrF excimer laser wavelength region, and has high light transmittance, that is, it can sufficiently reach light over the entire film thickness, and is fine after development processing. Further, it is possible to provide a photosensitive composition which can form a resist pattern having a good cross-sectional shape and high resolution, and can be effectively used in a photoetching process for manufacturing a highly integrated semiconductor device or the like.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location H01L 21/027 (72) Inventor Rumiko Hayase 1 Komukai Toshiba-cho, Kawasaki-shi, Kanagawa Prefecture Corporate Toshiba Research Institute (72) Inventor Yoshihito Kobayashi 1 Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Stock company Toshiba Research Institute

Claims (2)

[Claims] 1. A polymer in which a dissolution inhibiting group unstable to an acid is bonded to a hydroxyl group in the phenol skeleton of a hydrogenated alkali-soluble polymer having a phenol skeleton, and an acid The photosensitive composition containing the compound which generate | occur | produces. 2. The photosensitive composition according to claim 1, further comprising an alkali-soluble polymer having a phenolic hydroxyl group.