JP2981094B2 - Radiation-sensitive resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel radiation-sensitive resin composition which can be used as a constituent material of a resist used in the manufacture of semiconductor devices and which is sensitive to radiation such as photoelectron beam, X-ray and ion beam. It is about.

[0002]

2. Description of the Related Art In recent years, a processing technology on the order of submicrons has become necessary with the increasing integration of LSIs.
For this reason, for example, in an etching process in an LSI, a dry etching technique capable of performing highly accurate and fine processing is employed.

Here, the dry etching technique means that a substrate to be processed is covered with a resist, the resist is patterned using light, an electron beam, or the like, and the obtained pattern is used as a mask to form an etching mask using a reactive gas plasma. This is a technique for etching the substrate portion exposed from the substrate. Therefore, the resist used in the dry etching technique needs to be made of a material having a resolution on the order of submicrons and sufficient resistance to reactive gas plasma.

Meanwhile, as the integration and speed of LSIs increase, patterns with high aspect ratios are formed on substrates to be processed. Therefore, the thickness of the resist layer tends to be increased so that the steps can be flattened and the resist layer is maintained as an etching mask until the processing is completed. As a result, when the resist is exposed with light, the depth of focus of the exposure optical system is significantly restricted, and when the resist is drawn on the resist with an electron beam, the electron scattering phenomenon is significantly affected. For this reason, the resolution of the resist is reduced, and it is becoming difficult to process the substrate as desired with a single resist layer.

Therefore, a resist process called a two-layer resist method (two-layer resist process) is being studied as one of new resist processes. In order to flatten the steps of the substrate, a thick polymer layer (hereinafter, referred to as a lower layer, usually made of polyimide or a thermosetting photoresist) and O formed on the polymer layer are used.
_This is a resist process using a thin photoresist layer or an electron beam resist layer (hereinafter referred to as an upper layer) having _2- RIE resistance. Specifically, the upper layer plays a role of obtaining a high-resolution pattern, and the lower layer is patterned by O ₂ -RIE using the pattern of the upper layer as a mask to obtain a dry etching mask for processing the substrate.
Therefore, the upper layer resist has a higher O ₂ than the lower layer.
-It is necessary to use one having RIE resistance. As a conventional example of the radiation-sensitive resin composition used for such an upper resist, there has been a photosensitive resin composition patterned by light as described below.

First, the one disclosed in Japanese Patent Application Laid-Open No. 61-20030. This is a composition composed of a resin having a double bond such as poly (acryloyloxymethylphenylethylsilsesquioxane) and bisazide, and can be used as a highly sensitive UV resist under a nitrogen atmosphere. there were.

[0007] Japanese Patent Publication No. 60-49647 discloses a photosensitive resin composition using polysilane as a photopolymerization initiator. Specifically, it has been shown that a composition comprising poly (organosiloxane) having a double bond and dodecamethylcyclohexasilane has good properties as an ultraviolet curable resin.

Further, Japanese Patent Application Laid-Open No. 55-127523 discloses a photosensitive resin composition using an organic peroxide as a photopolymerization initiator. Specifically, a composition using a poly (organosiloxane) having a double bond and a suitable organic peroxide (such as a peroxyester) is irradiated with ultraviolet rays to form a uniform cured film. It is shown that

Further, as a photosensitive resin composition for an upper resist based on a completely different idea from the above-mentioned compositions,
Some were as described below.

For example, one disclosed in JP-A-61-144639. This can be accomplished by adding poly (phenylsilsesquioxane) and cis-resist to a general-purpose positive photoresist such as OFPR-800 (resist manufactured by Tokyo Ohka Kogyo Co., Ltd.).
(1,3,5,7-tetrahydroxy 9-1,3,5
A small amount of 7-tetraphenylcyclotetracycloxane is added. This can be used as a positive resist that can be developed with alkali.

The use of a substance other than poly (siloxane) as a binder has also been studied. For example, in JP-A-61-198151, a novolak resin having a trialkylsilyl group is used together with a diazonaphthoquinone photosensitizer. This can be used as a positive resist having sensitivity to visible light.

[0012]

However, when the conventional photosensitive resin composition is used as an upper resist in a two-layer resist process, there are the following problems.

In general, the photocuring reaction that proceeds via organic radicals is inhibited by oxygen. According to this principle, in the case of a photocurable photosensitive resin composition (for example, JP-A-61-20030 using bisazide as a photopolymerization initiator)
In the case of the photosensitive resin composition disclosed in Japanese Unexamined Patent Publication (Kokai) No. HEI-6-260, high sensitivity could not be attained unless exposure was performed in a nitrogen atmosphere. This problem also occurs in the case of the photosensitive resin composition disclosed in Japanese Patent Application Laid-Open No. 55-127023 in which the photopolymerization initiator is composed of an organic peroxide. Therefore, these compositions require a long time for curing, although the properties of the cured film can be improved by using an organic peroxide.

According to the knowledge of the inventor of this application, the photosensitive resin composition disclosed in Japanese Patent Publication No. 60-49647 using polysilane as a photopolymerization initiator is not as effective as a composition using bisazide. However, the presence of oxygen hinders the increase in sensitivity.

[0015] If the above problems are encountered, the throughput cannot be increased when exposure is performed in an oxygen atmosphere.
In order to perform exposure in a nitrogen atmosphere, various facilities for supplying nitrogen near the wafer are required.

Further, a photosensitive resin composition disclosed in Japanese Patent Application Laid-Open No. 61-144639, in which a silicon compound is added to a general-purpose photoresist, and a material other than poly (siloxane) is used as a binder. JP 61
The photosensitive resin composition disclosed in JP-A-198151 does not show sufficient O ₂ -RIE resistance because the silicon content of the silicon compound to be added and the silicon content of the binder used are low.

Therefore, the inventor of the present application disclosed in Japanese Patent Application No. 4-17588 a radiation-sensitive resin composition having high sensitivity to radiation and excellent O ₂ -RIE resistance (oxygen plasma resistance). Has been proposed. As shown in the following formula (7), this composition comprises a poly (siloxane) having a t-butoxy group, which is an acid-decomposable substituent, in each monomer unit (unit) and an acid by the action of radiation. It is composed of a mixture with a substance (acid generator) to be generated.

Then, as shown in the following reaction formula (8), this composition is gelled by exposure to radiation and heating after exposure to be converted into a substance equivalent to SiO ₂ . Since the conversion reaction proceeds catalytically, the amount of exposure light is extremely small. Therefore, this composition can be used as a sensitive resist. Further, there is an advantage that a resist pattern generated from this composition can be used as an etching mask as it is.

[0019]

Embedded image

However, when this composition is used in a two-layer resist process, a rectangular cross-section is required as an etching mask for a substrate, similarly to a normal resist pattern. Therefore, high anisotropy is required when etching the lower resist. Therefore, in order to suppress lateral etching due to radicals, it is necessary to etch the lower resist under a relatively low gas pressure.
Since a thick lower resist is etched under a low gas pressure, the time required for the etching is long. As a result, many upper layer masks are also sputter-etched. In particular, a film mainly composed of light atoms such as silicon is physically etched to a considerable extent. As a result, the upper layer mask is tapered, which causes a problem in dimensional controllability.

In the LSI manufacturing process, in the case of a two-layer resist process, an upper layer pattern is formed and then the upper layer pattern is inspected. If the upper layer pattern is defective, the once formed upper layer pattern is peeled off with a chemical. . However, since the gelled resist contains SiO ₂ , it does not dissolve in an oxidizing agent or an alkali.

The present invention has been made in view of the above points, and it is therefore an object of the present invention to have high sensitivity to radiation, high O ₂ -RIE resistance, and easy peeling. An object of the present invention is to provide a novel radiation-sensitive resin composition.

[0023]

In order to achieve this object, according to the radiation-sensitive resin composition of the first invention of the present application (hereinafter, also simply referred to as "composition"), the invention is simply described. C-O- decomposed by the action of acid for each monomer unit
It is characterized by containing poly (germyloxane) having a Ge bond and an acid generator that decomposes under the action of radiation to generate an acid.

Preferably, poly (germyloxane) is converted to a monomer unit represented by the following formula (1) and (2)
It is preferable to use a polymer of at least one kind of the monomer units represented by the formula. However, R in the formulas (1) and (2) is hydrogen, an alkyl group, or an arylmethyl group.

[0025]

Embedded image

According to the composition of the second aspect of the present invention, C is decomposed by the action of an acid for each monomer unit.
It is characterized by containing a poly (stannoxane) having an —O—Sn bond and an acid generator that decomposes under the action of radiation to generate an acid.

Also preferably, poly (stannoxane)
Is preferably composed of a polymer of at least one kind of a monomer unit represented by the following formula (3) and a monomer unit represented by the formula (4). However, R in the formulas (3) and (4) is hydrogen, an alkyl group, or an arylmethyl group.

[0028]

Embedded image

Further, according to the composition of the third aspect of the present invention, C is decomposed by the action of an acid for each monomer unit.
It is characterized by comprising a poly (titanoxane) having an -O-Ti bond and an acid generator that decomposes under the action of radiation to generate an acid.

Preferably, poly (titanoxane) is used.
Is preferably composed of a polymer of at least one kind of a monomer unit represented by the following formula (5) and a monomer unit represented by the formula (6). Here, R in the formulas (5) and (6) is hydrogen, an alkyl group, or an arylmethyl group.

[0031]

Embedded image

Hereinafter, poly (germyloxane), poly (stannoxane) and poly (titanoxane) will be collectively described as a polymer.

In each of the compositions of the present invention according to this application, an acid is generated from an acid generator in a portion irradiated with radiation (hereinafter also referred to as an exposed portion). This acid cleaves the C—O bond of the side chain of the polymer in the irradiated portion. Then, the polymers in which the side chains have been cut are condensed to gel the composition. Since the gelled portion becomes insoluble in the developing solution, each composition of the present invention can be used as a negative resist.

Furthermore, each of the compositions according to the present application is gelled by the catalytic action of a small amount of acid from the acid generator. For this reason, the exposure amount at the time of exposing each composition may be an exposure amount capable of generating a desired acid from the acid generator. Therefore, each composition according to this application has the same high sensitivity as the composition proposed in Japanese Patent Application No. 4-17588.

Further, each of the compositions according to this application is converted into a substance equivalent to germanium dioxide, tin dioxide and titanium dioxide (hereinafter collectively referred to as oxides) in the exposed portions. . These oxides are composed of Ge, Sn and Ti, which have a higher atomic weight than Si.
Respectively, so the above-mentioned poly (siloxane)
O ₂ − compared to a material equivalent to SiO ₂
RIE resistance is higher.

Further, none of the oxides produced from the compositions according to the present application contains Si. For this reason, the resist layer can be easily removed by a chemical such as a sulfuric acid / hydrogen peroxide mixture.

The range of the weight average molecular weight of the polymer used in each composition of the present invention is preferably from 500 to 100,000, more preferably from 1,000 to 50,000. When the weight molecular weight is less than 500, the resist film becomes sticky and particles (dust in the air and the like) easily adhere to the film. On the other hand, when the weight molecular weight is larger than 100,000, the solubility in a solvent is reduced, and thus coating unevenness is likely to occur when the resist is coated.

The acid which triggers the above-mentioned gelation reaction of the polymer is the second acid of each of the compositions of the first to third inventions.
Is supplied as a decomposition product by irradiation from the acid generator as a component of the above. The acid generator used in the radiation-sensitive resin composition of the present invention must generate a strong acid. As such, for example, various sulfonium salts represented by the following formulas (I) and (II), various iodonium salts represented by the following formulas (III) and (IV), and the following formula (V) Can be used.

[0039]

Embedded image

X in the formulas (I) to (IV) is, for example, BF ₄ , AsF ₆ , SbF ₆ , ClO ₄ , CF ₃ S
Represents O _3, and R in the formula (V) represents, for example, a group represented by the following formulas (A) and (B).

[0041]

Embedded image

Further, as the acid generators represented by the formulas (I) to (V), for example, those supplied from Midori Kagaku can be used. Alternatively, the literature “Journal of Polymer Science, Polymer, Chemistry Edition (J. Polymer Science, P.
polymer Chem. Ed,). 18,2677
(1980) ". It can also be synthesized by the method by Crivero et al.

It is desirable that the amount of the acid generator added to the polymer is in the range of 0.005 to 20 mol%. If the addition amount is less than 0.005 mol%, the sensitivity of the composition to radiation decreases, and as a result, the resolution of the composition decreases. On the other hand, when the addition amount is larger than 20 mol%, the thermal stability of the resist film containing this composition is deteriorated, and unevenness in application tends to occur when a resist containing this composition is applied.

Further, tin dioxide and titanium dioxide respectively produced from the compositions of the second and third inventions according to this application show conductivity. For example, the specific resistance of titanium dioxide is relatively low at about 10 ⁶ Ω · cm. Therefore, if the composition of the second or third invention is used as an intermediate layer of a three-layer resist for electron beam lithography, for example, an effect of preventing charge-up of the resist layer can be expected. As a result, it is expected that the drawing accuracy by the electron beam is improved.

[0045]

EXAMPLES Examples of the radiation-sensitive resin composition of the present invention will be described below. In addition, numerical conditions such as used materials and their amounts, processing time, processing temperature, and film thickness, which are mentioned in the following description, are merely preferred examples within the scope of the present invention. Therefore, the present invention is not limited only to these conditions.

First Example Hereinafter, examples of the radiation-sensitive resin composition of the first invention according to the present application will be described.

1-1. Synthesis Example of Poly (germyloxane) Here, as an example of poly (germyloxane), a synthesis example of poly (di-t-butoxygermyloxane) represented by the following formula (9) will be described.

In the synthesis, germane tetrachloride is boiled in acetic acid to induce germane tetraacetate, which is reacted with a predetermined amount of potassium t-butoxide to give diacetoxydi-
Obtain t-butoxygermane. This is hydrolyzed and polymerized in the presence of triethylamine to give poly (di-t
-Butoxygermiloxane).

[0049]

Embedded image

Next, a method for synthesizing (di-t-butoxygermiloxane) will be specifically described. First, 21.4 g of germane tetrachloride was dissolved in 200 ml of acetic acid, and the solution was heated.
Reflux for hours. Next, the excess acetic acid is distilled off under reduced pressure,
The residue is dissolved in 200 ml of THF (tetrahydrofuran). Then, the mixture is cooled on ice, and 25.2 g of potassium t-butoxide is added little by little. After stirring for 2 hours, the temperature is raised to room temperature. The reaction is further continued for 2 hours. Next, 300 ml of MIBK (methyl isobutyl ketone) and 20.2 g of triethylamine are added to the solution, and cooled to a temperature of -20 ° C. 18 g of water are added dropwise to this. After allowing the reaction to proceed for 1 hour, the temperature is raised to room temperature over 1 hour. Next, it is heated to a temperature of 60 ° C. and reacted for 4.5 hours. After cooling, the reaction is transferred to a separatory funnel to extract organics. After washing the organic layer of the separating funnel, it is dried and the solvent is distilled off. Next, the remaining organic matter is dissolved in a small amount of ethyl acetate and poured into n-hexane to obtain a white precipitate. In this synthesis example, this was vacuum-dried to obtain 18.6 g of poly (di-t-butoxygermiloxane).

When the obtained poly (di-t-butoxygermiloxane) was measured by NMR, t-
A peak derived from the ethyl proton group of butyl was observed. Also, GPC (gel permeation chromatography) Results of molecular weight measurement by the weight average molecular weight M _W is 3500,
The molecular weight distribution M _w / M _n was 1.4.

1-2. Evaluation Example of Radiation Resin Composition (Single Layer) First, 2.35 g of the poly (di-t-butoxygermyloxane) obtained in the above-mentioned synthesis example and a molecular weight of 234.6 in terms of a monomer unit of 0. 0.5 mol% (22 m
g) of triphenylsulfonium triflate in MIB
Dissolve in 20 ml of K to prepare a resist solution. next,
This solution is spin-coated on a silicon substrate. Next, it is baked on a hot plate at a temperature of 80 ° C. for 1 minute. Next, a test pattern is drawn on this with an electron beam having an acceleration voltage of 20 kV. Next, this was baked at 80 ° C. for 2 minutes, developed with anisole, and then rinsed with cyclohexane. When the pattern of the obtained sample was observed by SEM, it was found that a 0.3 μm line and space could be resolved. The exposure amount at this time is 1.
It was 50 μC / cm ² .

1-2-1. Confirmation of Easy Peeling of Resist (Part 1) The sample obtained in the above-mentioned evaluation example (Part 1) was immersed in a mixed solution of concentrated sulfuric acid 3: hydrogen peroxide solution 1 heated to a temperature of 110 ° C. for 10 minutes. Thereafter, the substrate was washed with pure water for 10 minutes. When the washed sample was observed with an optical microscope, it was found that the pattern of the sample on the silicon substrate had completely dissolved and removed.

1-2-2. Confirmation of easiness of resist stripping (Part 2) The sample obtained in the above-mentioned evaluation example (Part 2) was treated with fuming nitric acid for 10 minutes.
After soaking for 10 minutes, the substrate was washed with pure water for 10 minutes. When the washed sample was observed with an optical microscope, it was found that the pattern of the sample on the silicon substrate had completely dissolved and removed.

1-3. Evaluation Example of Radiation Resin Composition (Two-Layer Resist Process) Here, 2.35 g of the poly (di-t-butoxygelmiloxane) obtained in the above synthesis example and a molecular weight of 234.6 in terms of a monomer unit were used. 0.5 mol% (22
mg) of triphenylsulfonium triflate
The resist solution is prepared by dissolving in 20 ml of BK. Next, this solution is spin-coated on a 1.5 μm thick thermoset photoresist layer. Next, it is baked on a hot plate at a temperature of 80 ° C. for 1 minute. Next, a test pattern is drawn on this with an electron beam having an acceleration voltage of 20 kV. Next, this was baked at 80 ° C. for 2 minutes, developed with anisole, and then rinsed with cyclohexane.

Next, oxygen plasma etching (O ₂ -RIE) was performed on the rinsed pattern. The etching conditions were a parallel plate type dry etcher, a power density of 0.12 W / cm ² , an oxygen flow rate of 50 sccm, a gas pressure of 1.5 Pa, and an etching time of 30 minutes. Next, when the etched pattern was observed with a SEM, a line and space of 1.5 μm in height and 0.3 μm in line and space were observed.
It was found that the layer resist pattern was resolved.
The exposure at this time was 2.0 μC / cm ² .

Second Example Hereinafter, an example of the radiation-sensitive resin composition of the second invention according to this application will be described.

2-1. Synthesis Example of Poly (stannoxane) Here, a synthesis example of poly (di-t-butoxystanoxane) represented by the following formula (10) will be described as an example of poly (stannoxane).

In the synthesis, tin tetrachloride is boiled in acetic acid to induce tin tetraacetate, which is reacted with a predetermined amount of potassium t-butoxide to obtain diacetoxydi-t-butoxystanan. This is hydrolyzed and polymerized in the presence of triethylamine to obtain poly (di-t-butoxystannoxane).

[0060]

Embedded image

Next, (di-t-butoxystannoxane)
The method for synthesizing is specifically described. First, tin tetrachloride 2
Dissolve 1.4 g in 200 ml of acetic acid and heat to reflux for 4 hours. Next, excess acetic acid is distilled off under reduced pressure, and the residue is dissolved in 200 ml of THF. Next, cool it on ice,
25.2 g of potassium t-butoxide are added in portions.
After stirring for 2 hours, the temperature is raised to room temperature. The reaction is further continued for 2 hours. Next, add MIB to this solution.
K300 ml and triethylamine 20.2 g were added,
Cool to a temperature of 20 ° C. 18 g of water are added dropwise to this. After allowing the reaction to proceed for 1 hour, the temperature is raised to room temperature over 1 hour. Next, it is heated to a temperature of 60 ° C. and reacted for 2.5 hours. After cooling, the reaction is transferred to a separatory funnel to extract organics. After washing the organic layer of the separating funnel, it is dried and the solvent is distilled off. Next, the remaining organic matter is dissolved in a small amount of ethyl acetate and poured into n-hexane to obtain a white precipitate. In this synthesis example, this was vacuum-dried to obtain 19.6 g of poly (di-t-butoxystannoxane).

When the obtained poly (di-t-butoxystannoxane) was measured by NMR, a peak derived from an ethyl proton group of t-butyl was observed at 1.2 ppm. As a result of molecular weight measurement by GPC, the weight-average molecular weight M _W is 2400, the molecular weight distribution M _W / M _n was 1.2.

2-2. Evaluation Example of Radiation Resin Composition (Single Layer) First, 2.81 g of poly (di-t-butoxystannoxane) obtained in the above synthesis example and 0.5 mol based on the molecular weight 281 in terms of a monomer unit. % (22 mg) of triphenylsulfonium triflate with MIBK20m
1 to prepare a resist solution. Next, this solution is spin-coated on a silicon substrate. Next, it is baked on a hot plate at a temperature of 80 ° C. for 1 minute. Next, a test pattern is drawn on this with an electron beam having an acceleration voltage of 20 kV. Next, this was baked at 80 ° C. for 2 minutes, developed with anisole, and then rinsed with cyclohexane. When the pattern of the obtained sample was observed by SEM, it was found that a 0.3 μm line and space could be resolved. The exposure at this time is 0.8μ
C / cm ² .

2-3. Comparative Example of O ₂ -RIE resistance Next, a comparative example of O ₂ -RIE resistance of a composition comprising a poly (stannoxanes) and poly (siloxane) compositions comprising.

First, according to the same method as the above-mentioned evaluation example,
A resist solution containing poly (di-t-butoxystannoxane) is prepared. Next, this resist solution is spin-coated on a silicon substrate. Next, it was baked on a hot plate at a temperature of 80 ° C. for 1 minute. Next, exposure to deep UV is performed for one minute using a PLA501 aligner (trade name) manufactured by Canon equipped with a Xe-Hg lamp. Next, this is baked at 80 ° C. for 2 minutes,
An 80 μm cured film was obtained. This cured film is referred to as Sample A.

Next, a poly (di-t-butoxysiloxane) having an average molecular weight of 3500 and a separation amount dispersion of 1.4, and 0.5 mol of the poly (di-t-butoxysiloxane) having a molecular weight of 190 in terms of a monomer unit.
A resist solution is prepared by dissolving 1% of triphenylsulfonium triflate in cyclohexanone. next,
This resist solution is spin-coated on a silicon substrate to form a cast film. Hereinafter, the film thickness 3
20 cured films are obtained. This cured film was used as sample B
And

Next, oxygen plasma etching is performed on each of the sample A and the sample B. At the time of etching, DEM451 (trade name) manufactured by Nidec Anelva was used, oxygen gas pressure was 0.5 Pa, and power density was 0.16 W / cm ^2.
Etching was performed for 2 minutes under the conditions described above.

After the etching, the amount of decrease in the film thickness of Samples A and B was measured.
Was 15 nm / min, and that of Sample B was 9 nm / min. Thus, poly (di-t-butoxystannoxane)
The etching mask formed from the composition containing O ₂ − is more O ₂ − than the one containing poly (di-t-butoxysiloxane).
It can be seen that the RIE resistance is high.

2-4. Evaluation Example of Radiation Resin Composition (Two-Layer Resist Process) First, poly (di-t-t) was prepared by the same method as the evaluation example described above.
-Butoxystannoxane) is prepared. Next, this solution is spin-coated on a 1.5 μm thick thermoset photoresist layer. Next, it is baked on a hot plate at a temperature of 80 ° C. for 1 minute. next,
Then, a test pattern is drawn with an electron beam having an acceleration voltage of 20 kV. Next, this was baked at 80 ° C. for 2 minutes, developed with anisole, and then rinsed with cyclohexane. Next, oxygen plasma etching (O ₂ -RIE) was performed on the rinsed pattern. The etching conditions were a parallel plate type dry etcher, a power density of 0.16 W / cm ² , an oxygen flow rate of 50 sccm, a gas pressure of 0.8 Pa, and an etching time of 30 minutes. Next, when the etched pattern was observed by SEM, it was found that a 0.3 μm line-and-space two-layer resist pattern having a height of 1.5 μm was resolved. The exposure at this time was 2.0 μC / cm ² .

Third Example Hereinafter, examples of the radiation-sensitive resin composition of the third invention according to the present application will be described.

3-1. Synthesis Example of Poly (titanoxane) First, as an example of poly (titanoxane), poly (di-t-butoxytitanoxane) represented by the following formula (11)
Will be described.

In the synthesis, titanium tetrachloride is boiled in acetic acid to induce titanium tetraacetate, which is reacted with a predetermined amount of potassium t-butoxide to give diacetoxydi-t-toxide.
Obtain butoxystannane. This is hydrolyzed and polymerized in the presence of triethylamine to obtain poly (di-t-butoxytitanoxane).

[0073]

Embedded image

Next, (di-t-butoxytitanoxane)
The method for synthesizing is specifically described. First, titanium tetrachloride 2
1 g is dissolved in 200 ml of acetic acid and heated to reflux for 4 hours. Next, excess acetic acid is distilled off under reduced pressure, and the residue is
Dissolve in 200 ml of HF. Then, the mixture is cooled on ice, and 25.2 g of potassium t-butoxide is added little by little. After stirring for 1 hour, the temperature is raised to room temperature. The reaction is further continued for 2.5 hours. Next, after cooling, the reaction product is transferred to a separating funnel to extract organic substances. After washing the organic layer of the separating funnel, it is dried and the solvent is distilled off. Next, the remaining organic matter is dissolved in a small amount of ethyl acetate and poured into n-hexane to obtain a white precipitate. In this synthesis example,
This was vacuum dried to obtain 18.6 g of poly (di-t-butoxytitanoxane).

When the obtained poly (di-t-butoxytitanoxane) was measured by NMR, a peak derived from an ethyl proton group of t-butyl was observed at 1.2 ppm. As a result of molecular weight measurement by GPC, the weight-average molecular weight M _W is 2800, the molecular weight distribution M _W / M _n was 1.2.

3-2. Evaluation Example of Radiation Resin Composition (Single Layer) Here, 2.1 g of the poly (di-t-butoxytitanoxane) obtained in the above-mentioned synthesis example, and 0.1 g of the molecular weight 210 in terms of monomer unit. 5 mol% (22 mg) of triphenylsulfonium triflate was added to MIBK20.
The solution is dissolved in the solution to prepare a resist solution. Next, this solution is spin-coated on a silicon substrate. Next, it is baked on a hot plate at a temperature of 80 ° C. for 1 minute. Next, a test pattern is drawn on this with an electron beam having an acceleration voltage of 20 kV. Next, this was baked at 80 ° C. for 2 minutes, developed with anisole, and then rinsed with cyclohexane. When the pattern of the obtained sample was observed by SEM, it was found that a 0.3 μm line and space could be resolved. The exposure amount at this time is 1.3 μm.
C / cm ² .

3-3. Comparative Example of O ₂ -RIE resistance Next, a comparative example of O ₂ -RIE resistance of a composition comprising a poly (Chitanokisan) and poly (siloxane) compositions comprising.

First, according to the same method as in the above-described evaluation example,
A resist solution containing poly (di-t-butoxytitanoxane) is prepared. Next, this resist solution is spin-coated on a silicon substrate. Next, it was baked on a hot plate at a temperature of 80 ° C. for 1 minute. Next, exposure to deep UV is performed for one minute using a PLA501 aligner (trade name) manufactured by Canon equipped with a Xe-Hg lamp. Next, this is baked at 80 ° C. for 2 minutes to give a film thickness of 3
A cured film of 50 μm was obtained. This cured film is referred to as Sample A.

Next, a poly (di-t-butoxysiloxane) having an average molecular weight of 3,500 and a separation amount dispersion of 1.4, and 0.5 mol of the poly (di-t-butoxysiloxane) having a molecular weight of 190 in terms of monomer unit
A resist solution is prepared by dissolving 1% of triphenylsulfonium triflate in cyclohexanone. next,
This resist solution is spin-coated on a silicon substrate to form a cast film. Hereinafter, the film thickness 3
20 cured films are obtained. This cured film was used as sample B
And

Next, oxygen plasma etching is performed on each of the sample A and the sample B. At the time of etching, DEM451 (trade name) manufactured by Nidec Anelva was used, oxygen gas pressure was 0.5 Pa, and power density was 0.16 W / cm ^2.
Etching was performed for 2 minutes under the conditions described above.

After the etching, the amount of decrease in the film thickness of Samples A and B was measured.
Was 15 nm / min, and that of Sample B was 10 nm / min. Thus, an etch mask generated from a composition containing poly (di-t-butoxytitanoxane) will have a higher O ₂ than that containing poly (di-t-butoxy siloxane).
-It turns out that RIE resistance is high.

3-4. Comparison of Ease of Peeling of Resist Next, a comparative example of the ease of peeling of the composition containing poly (titanoxane) and the composition containing poly (siloxane) will be described.

The above samples A and B were immersed in a mixed solution of concentrated sulfuric acid 3: hydrogen peroxide solution 1 heated to a temperature of 100 ° C. for 30 minutes, and then washed with pure water. Observation of each washed sample with an optical microscope showed that the pattern of the sample A on the silicon substrate was completely dissolved and removed, while the pattern of the sample B was completely left.

3-5. Evaluation Example of Radiation Resin Composition (Two-Layer Resist Process) First, poly (di-t-t) was prepared by the same method as the evaluation example described above.
-Butoxytitanoxane) is prepared. Next, this solution is spin-coated on a 1.5 μm thick thermoset photoresist layer. Next, it is baked on a hot plate at a temperature of 80 ° C. for 1 minute. next,
Then, a test pattern is drawn with an electron beam having an acceleration voltage of 20 kV. Next, this was baked at 80 ° C. for 2 minutes, developed with anisole, and then rinsed with cyclohexane. Next, oxygen plasma etching (O ₂ -RIE) was performed on the rinsed pattern. The etching conditions were a parallel plate dry etcher, a power density of 0.16 W / cm ² , an oxygen flow rate of 50 sccm ² , a gas pressure of 0.8 Pa, and an etching time of 30 minutes. Next, when the etched pattern was observed by SEM, it was found that a 0.3 μm line-and-space two-layer resist pattern having a height of 1.5 μm was resolved. The exposure amount at this time was 1.5 μC / cm ² .

In each of the above-described embodiments, the radiation-sensitive resin composition of the present invention was exposed using an electron beam and deep UV as the radiation. However, the radiation used for the exposure is not limited to an electron beam or the like. The same effect as that of the embodiment can be obtained with other radiation such as an ion beam.

[0086]

As is clear from the above description, in the radiation-sensitive resin composition of the present invention, an acid is generated from an acid generator in a portion (exposed portion) irradiated with a radiation beam, and After the acid has cleaved the C—O bond of the exposed portion of the polymer, gelation by polymerization produces a substance substantially equivalent to the oxide. For this reason, since this part becomes insoluble in the developing solution, this radiation-sensitive resin composition can be used as a negative resist. Also, this oxide has
Since it contains atoms (Ge, Sn or Ti) having an atomic weight larger than that of Si of iO ₂ , O ₂ —RI is higher than SiO _2.
A resist excellent in E resistance can be obtained. Further, since the oxides produced from the composition of the present invention do not contain any Si, for example, the resist layer can be easily peeled off with a chemical.

Therefore, the composition of the present invention can be used for manufacturing a semiconductor device without reducing the throughput of lithography using a resist using an electron beam or a deep UV of a mercury lamp as a light source. Further, since the composition of the present invention can be developed with an alkali developing solution, the compatibility with the existing resist process is good.

Further, both tin dioxide and titanium dioxide produced from the compositions of the second and third inventions according to this application show conductivity. For example, the specific resistance of titanium dioxide is relatively low at about 10 ⁶ Ω · cm. Therefore, if the composition of the second or third invention is used as an intermediate layer of a three-layer resist for electron beam lithography, for example, an effect of preventing charge-up of the resist layer can be expected. As a result, it is expected that the drawing accuracy by the electron beam is improved.

────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ identification symbol FI H01L 21/312 H01L 21/30 573 (56) References JP-A-4-127159 (JP, A) JP-A-1-103611 ( JP, A) JP-A-62-288041 (JP, A) JP-A-3-278059 (JP, A) JP-A-4-145441 (JP, A) JP-A-5-61197 (JP, A) JP-A-5-66563 (JP, A) JP-A-5-224422 (JP, A) JP-A-6-130667 (JP, A) JP-A-6-130665 (JP, A) JP-A-6-43651 (JP) , A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03F 7/038 G03F 7/095 G03F 7/26

Claims (9)

(57) [Claims] 1. Poly (germyloxane) having a C—O—Ge bond decomposed by the action of an acid for each monomer unit
And an acid generator that decomposes under the action of radiation to generate an acid, wherein the poly (germyloxane) is a monomer unit represented by the following formula (1) and a monomer represented by the following formula (2) A radiation-sensitive resin composition comprising a polymer of at least one type of monomer unit (wherein (1)
R in the formula and (2) is hydrogen, an alkyl group, or an arylmethyl group. ). Embedded image 2. The radiation-sensitive resin composition according to claim 1, wherein the poly (germyloxane) has a weight average molecular weight in the range of 500 to 100,000. 3. The radiation-sensitive resin composition according to claim 1, wherein the amount of the acid generator added to the poly (germyloxane) is in the range of 0.005 to 20 mol%. Sensitive resin composition. 4. A poly (stannoxane) having a C—O—Sn bond decomposed by the action of an acid for each monomer unit,
An acid generator that decomposes under the action of radiation to generate an acid, wherein the poly (stannoxane) is a monomer unit represented by the following formula (3) and a monomer unit represented by the following formula (4): A radiation-sensitive resin composition characterized by comprising a polymer of at least one kind of monomer unit (provided that R in the formulas (3) and (4) represents hydrogen, an alkyl group, or An arylmethyl group). Embedded image 5. The radiation-sensitive resin composition according to claim 4, wherein the weight average molecular weight of the poly (stannoxane) is 500.
A radiation-sensitive resin composition, which is in the range of １００100,000. 6. The radiation-sensitive resin composition according to claim 4, wherein the amount of the acid generator added to the poly (stannoxane) is in the range of 0.005 to 20 mol%. Sensitive resin composition. 7. A poly (titanoxane) having a C—O—Ti bond decomposed by the action of an acid for each monomer unit,
An acid generator that decomposes under the action of radiation to generate an acid, wherein the poly (titanoxane) is a monomer unit represented by the following formula (5) and a monomer unit represented by the following formula (6): A radiation-sensitive resin composition comprising a polymer of at least one of the monomer units (where R in the formulas (5) and (6) is hydrogen, an alkyl group, or An arylmethyl group). Embedded image 8. The radiation-sensitive resin composition according to claim 7, wherein the weight average molecular weight of the poly (titanoxane) is 500.
A radiation-sensitive resin composition, which is in the range of １００100,000. 9. The radiation-sensitive resin composition according to claim 7, wherein an addition amount of the acid generator to the poly (titanoxane) is in a range of 0.005 to 20 mol%. Sensitive resin composition.