JPH0525277A - Resist composition and production of organosilicon polymer - Google Patents

Abstract

PURPOSE:To produce a negative resist which is used for the upper layer of a double-layer resist and has an improved resolution without detriment to sensitivity and resistance to oxygen and plasma by using an organosilicon polymer having a structure wherein a silalkylene backbone having a random three- dimensional structure is sorrounded and blocked by triorganosilyl groups. CONSTITUTION:A resist compsn. which mainly comprises an organosilicon polymer of formula I (wherein R<1> is alkylene; R<2> is a monovalent hydrocarbon group provided that three R<2s> may be the same or different; and (m) and (n) are each a positive integer). The polymer is prepd, e.g. by hydrolyzing an organosilicon compd. of formula II, subjecting the hydrolyzate to polycondensation to give a polymer, and reacting the polymer with an organosilicon compd. selected from among organosilicon compds. of formulas III, IV, and V to substitute the hydroxl groups in the polymer with triorganosilyl groups of formula VI. In formulas II to VI, X is halogen, alkoxy, cyano, isocyanate, or thioisocyanate; and R<1> and R<2> are each as defined in formula I.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a negative resist for a two-layer structure upper layer and a method for producing an organic silicon polymer constituting the same.

Since it is necessary to process a large amount of information quickly, semiconductor devices that form the main body of information processing devices have been integrated and LSI and VLSI have been put into practical use. Here, integration is performed by miniaturizing the unit element, and the minimum line width of the wiring pattern reaches submicron.

Since multi-layer wiring is used,
There are many minute steps on a semiconductor wafer forming an integrated circuit. By the way, in the manufacture of semiconductor integrated circuits, selective exposure is performed after coating a resist on a semiconductor substrate,
Photolithography technology (photolithography or electron beam lithography) in which exposed areas or unexposed areas are dissolved by a developing process to open a resist window and then dry etching is performed to etch the conductive film or insulating film is essential.

Therefore, a multi-layer resist method having a three-layer structure or a two-layer structure is used as a method for forming a fine pattern with high accuracy by eliminating the influence of a step, but the two-layer resist method having a small number of steps is generally used. It is used for.

[0005]

2. Description of the Related Art When a two-layer structure resist method is used, the thickness of a resist layer directly patterned by exposure can be made much smaller than that of a single-layer resist method, so that high resolution can be realized.

Here, the resist applicable to the upper layer resist is required to have sufficient resistance to oxygen plasma, and the following organic silicon polymers are used. Poly-P-chloromethylphenyl siloxane, polyallyl silsesquioxane, polyvinyl silsesquioxane, etc.

However, since an organic solvent must be used for the development after exposure of a resist made of such a material, the resist swells sharply and the advantages of the two-layer structure resist method can be fully utilized. The resolution is not so improved.

Therefore, there is a problem that a resist pattern required for manufacturing a VLSI having a submicron pattern cannot be stably formed.

[0009]

The organic silicon polymer is used as an upper layer resist having a two-layer structure because the organic silicon polymer becomes insoluble in a developing solution due to the progress of crosslinking when exposed to light. Due to the large swelling of the insoluble portion of the resist, when forming a resist pattern of 0.5 μm or less, rough edges and bridges are likely to occur, and high resolution cannot be obtained.

Therefore, it is an object to improve the resolution without impairing the sensitivity and the oxygen plasma resistance.

[0011]

[Means for Solving the Problems] The above problems constitute the main component of a resist composition and are represented by the following general formula (2) as a method for producing an organic silicon polymer represented by the following general formula (1). Hydrolyzing an organic silicon compound and reacting the hydroxyl group contained in the polymer obtained by dehydration polycondensation with any one of the following general formulas (3), (4) and (5) , Characterized by being substituted with a triorganosilyl group represented by the following general formula (6), or the following general formula (3), (4),
At least one of the silicon compounds represented by (5) is dissolved in an organic solvent, and in the presence of water in this solution, the following general formula (2)
The organic silicon compound represented by is gradually added and dehydrated and polycondensed, and the hydroxyl group contained in this organic silicon compound is replaced by a triorganosilyl group represented by the following general formula (6). This can be solved by configuring the method for producing an organic silicon polymer described in (1).

(Si ₂ R ¹ O ₃ ) _m (R ² ₃ SiO _1/2 ) _n ... (1) X ₃ SiR ¹ SiX ₃ ... (2) R ² ₃ SiX ・ ・ ・ ・ ・ ・ (3) R ² ₃ Si-NH-SiR ² ₃・ ・ ・ ・ ・ ・ ・ ・ (4) R ² ₃ Si-O-SiR ² ₃・ ・ ・ ・ ・・ (5) R ² ₃ Si- ・ ・ ・ (6) Here, X represents a halogen group, an alkoxy group, a cyano group, an isocyanato group or an isocyanato group, and R ¹ represents an alkylene. , R ² represents a monovalent hydrocarbon group and may be the same or different.

[0013]

The inventors of the present invention intend to change the method for arranging the organic silicon polymer as a method for suppressing the swelling of the insolubilized portion which is cross-linked by the exposure when the resist made of the organic silicon polymer is exposed and developed. is there.

That is, in the conventional polymer, the --Si--O-- bond has a linear or ladder shape, and the end thereof is sealed with a triorganosilyl group, but the polymer according to the present invention is random. It has a structure in which a triorganosilyl group surrounds and seals the periphery of a silalkylene skeleton having a simple three-dimensional structure.

When such a three-dimensional structure is adopted, the softening temperature is increased as compared with the conventional linear structure or ladder type structure, and the movement of molecules in the developer is restricted, so that the swelling is suppressed. As a result, the resolution can be improved.

Here, according to the present invention, (Si ₂ R ¹ O ₃ ) _m (R ² ₃
As the alkylene represented by R ¹ in the organic silicon polymer represented by the general formula of SiO _1/2 ) _n , lower alkylene such as methylene, ethylene and propylene is applicable.

R ² represents a monovalent hydrocarbon group, which may be the same or different. Specifically, a methyl group,
Alkyl groups such as ethyl group, hexyl group, haloalkyl groups such as 1-chloromethyl group, 2-chloroethyl group, 3-chloropropyl group, 2-phenylethyl group, 2-phenylethyl group, 2-phenylpropyl group, etc. This includes aralkyl groups, alkoxy groups such as methoxy groups and ethoxy groups, alkenyl groups such as vinyl groups and allyl groups, aryl groups such as phenyl groups and tolyl groups, haloaryl groups such as parachlorophenyl, and epoxy groups.

Next, as a method for forming a resist, such an organic silicon polymer is dissolved in an organic solvent such as alcohol, ketone or ether, filtered using a filter having a pore size of about 0.1 μm, and then spin coated. 0.2 to 0.3 μ
The coating solution may be prepared by adjusting the concentration so that the film thickness becomes m.

[0019]

【Example】

Synthesis Example 1 (corresponding to claim 2) Methyl isobutyl ketone (MIBK) 50cc, acetone 25cc,
Dissolve 16 g of bis (trimethoxysilyl) methane in a mixed solvent consisting of 25 cc of methanol and add 5.4 cc of water at room temperature.
It was stirred for 30 minutes.

Then, the system was concentrated under reduced pressure to obtain about 20% by weight.
A resin solution of Then, 90 g of phenyldimethylchlorosilane and 90 g of pyridine were added, and the mixture was stirred at 80 ° C. for 2 hours.

After cooling, 100 cc of each of MIBK and water was added, the upper MIBK layer was taken using a separatory funnel and washed several times with water, and then the remaining water was removed by azeotropic distillation. Then, the reaction solution was poured into a large amount of water to precipitate and collect the resin, which was freeze-dried to obtain about 10 g of a white powder.

The weight average molecular weight of the product was 5.3 × 10 ^{3 in} terms of standard polystyrene and the dispersity was 2.8 as measured by Kelper permeation chromatography (abbreviated as GPC). Synthesis Example 2 (corresponding to claim 3) Methyl isobutyl ketone 40c in a 500cc four-necked flask
c, methanol 25cc, acetone 25cc, water 50cc, concentrated hydrochloric acid 5c
c and 4.05 g of hexamethyldisiloxane were charged and heated to a reflux state.

Next, 15.9 g of 1,2-bis (trimethoxysilyl) ethane was dissolved in 35 cc of MIBK and added dropwise into the flask over 20 minutes. After that, continue stirring for 30 minutes and then cool,
Add 50cc each of MIBK and water, and use the separating funnel to
The MIBK layer was taken, washed with water several times, and then the remaining water was removed by azeotropic distillation.

Then, the reaction solution was poured into a large amount of water to precipitate and collect the resin, which was freeze-dried to obtain about 12 g of a white powder. The weight average molecular weight of the product was 1.2 × 10 ^{4 in} terms of standard polystyrene and the dispersity was 4.0 as measured by Kelpermeation chromatography (abbreviated as GPC). Synthesis Example 3 (corresponding to claim 4) To 100 g of a 4% MIBK solution of the powder obtained in Synthesis Example 2 was added 10 cc each of trimethylchlorosilane and pyridine, and the mixture was heated at 80 ° C.
Stir for hours.

After cooling, 50 cc of each of MIBK and water was added, the upper MIBK layer was taken using a separatory funnel, washed several times with water, and then the remaining water was removed by azeotropic distillation. Then, the reaction solution was poured into a large amount of water to precipitate the resin, which was collected and freeze-dried to obtain 4.17 g of a white powder.

Then, low molecular weight oligomers and impurities were removed by washing with ethanol and acetonitrile to finally obtain 2.16 g of white powder. The weight average molecular weight of this was measured by Kelpermeation Chromatograph (abbreviated as GPC) to be 4.1 × 10 ^{4 in} terms of standard polystyrene.
It was 3.5. Synthetic Example 4 (corresponding to claim 4) To 100 g of a 4% MIBK solution of the powder obtained in Synthetic Example 2, 10 cc each of vinyldimethylchlorosilane and pyridine was added, and the mixture was heated to 80 ° C.
And stirred for 2 hours.

After cooling, 50 cc of each of MIBK and water was added, the upper MIBK layer was taken using a separatory funnel and washed several times with water, and then the remaining water was removed by azeotropic distillation. Then, the reaction solution was poured into a large amount of water to precipitate and collect the resin, which was freeze-dried to obtain 4.0 g of a white powder.

Then, low molecular weight oligomers and impurities were removed by washing with ethanol and acetonitrile to finally obtain 1.24 g of white powder. The weight average molecular weight of this was measured by Kelpermeation chromatography (abbreviated as GPC) to be 4.2 × 10 ^{4 in} terms of standard polystyrene.
It was 4.2. Synthesis Example 5 (corresponding to claim 4) To 100 g of a 4% MIBK solution of the powder obtained in Synthesis Example 2 was added 10 cc each of phenyldimethylchlorosilane and pyridine, and
The mixture was stirred at 0 ° C for 2 hours.

After cooling, 50 cc of each of MIBK and water was added, the upper MIBK layer was taken using a separatory funnel and washed several times with water, and then the remaining water was removed by azeotropic distillation. Then, the reaction solution was poured into a large amount of water to precipitate the resin, which was collected and freeze-dried to obtain 2.20 g of a white powder.

The weight average molecular weight of the polymer was 5.4 × 10 ^{4 in} terms of standard polystyrene and the dispersity was 2.9 as measured by Kelpermeation chromatography (abbreviated as GPC). Synthesis Example 6 (corresponding to claim 3) Methyl isobutyl ketone 50c in a 300cc four-necked flask
c, ethanol 25cc, acetone 25cc, water 50cc, concentrated hydrochloric acid 5c
C and 7.15 g of hexavinyldisiloxane were charged, and the mixture was heated and stirred to bring it to a reflux state.

Next, 20.1 g of 1,2-bis (triethoxysilyl) ethane was dropped into the flask over 20 minutes. Then, continue stirring for 20 minutes, then cool and mix MIBK and water respectively.
50 cc was added, the upper MIBK layer was taken using a separatory funnel, washed with water several times, and then the remaining water was removed by azeotropic distillation.

Then, the reaction solution was poured into a large amount of water to precipitate and collect the resin, which was freeze-dried to obtain about 15 g of a white powder. The weight average molecular weight of the product was 4.1 × 10 ^{4 in} terms of standard polystyrene and the dispersity was 5.6 as measured by Kelpermeation chromatography (abbreviated as GPC). Synthesis example 7 (corresponding to claim 4) To 85 g of a 14% MIBK solution of the powder obtained in synthesis example 2 was added 10 cc each of phenyldivinylchlorosilane and pyridine,
And stirred for 2 hours.

After cooling, 50 cc of each of MIBK and water was added, and the upper MIBK layer was taken using a separatory funnel and washed several times with water, and then the remaining water was removed by azeotropic distillation. Then, the reaction solution was poured into a large amount of water to precipitate and collect the resin, which was freeze-dried to obtain 10.4 g of white powder.

This polymer was dissolved in isopropyl alcohol and precipitated by a temperature difference, and molecular weight fractionation was performed. The weight average molecular weight of this was measured by Kelpermeation chromatography (abbreviated as GPC) in terms of standard polystyrene.
The dispersity was 3.5 × 10 ⁴ and was 1.8.

Example 1 (Example of use as electron beam resist) A 13% MIBK solution of the polymer obtained in Synthesis Example 7 was prepared and filtered through a membrane filter having a pore size of 0.1 μm to obtain a resist solution.

Next, a novolac-based resist (M
P-1300, Shipley Co., Ltd.) was applied to a thickness of 2.0 μm and hard baked to form a planarization layer. Onto this, the above resist solution was applied so as to have a thickness of 0.2 μm, and baked at 80 ° C. for 20 minutes.

The bilayer resist film thus obtained was scanned with an electron beam at an acceleration voltage of 20 KV, developed with MIBK for 60 seconds, and then rinsed with isopropyl alcohol for 30 seconds.

Next, the sample was placed in a parallel plate type dry etching apparatus, and oxygen plasma (vacuum degree 2 Pa, power 0.22 W) was used.
/ Cm ² ), dry etching was performed for 15 minutes to transfer the upper layer pattern to the lower layer.

As a result, a 0.5 μm line-and-space pattern could be resolved under the condition of electron beam exposure of 8 μC / cm ² . Example 2 (Example of use as photoresist) A 13% MIBK solution of the polymer obtained in Synthesis Example 7 was prepared, and this was filtered through a membrane filter having a pore size of 0.1 μm to obtain a resist solution.

Next, a novolac-based resist (M
P-1300, Shipley Co., Ltd.) was applied to a thickness of 2.0 μm and hard baked to form a planarization layer. Onto this, the above resist solution was applied so as to have a thickness of 0.2 μm, and baked at 80 ° C. for 20 minutes.

The two-layer resist film thus obtained has a wavelength of
After irradiating deep ultraviolet rays of 248 nmV, develop with MIBK for 60 seconds,
Then, a rinse treatment was performed for 30 seconds with isopropyl alcohol. Next, the sample was placed in a parallel plate type dry etching device and oxygen plasma (vacuum degree 2 Pa, power 0.22 W / cm ² ) was used.
Then, dry etching was performed for 15 minutes to transfer the upper layer pattern to the lower layer.

As a result, 0.5 μ was obtained under the condition of the exposure amount of 80 mJ / cm ^2.
I was able to resolve m line and space patterns.

[0043]

According to the present invention, it is possible to obtain an organic silicon polymer which is a resist having high sensitivity and oxygen plasma resistance and high swelling and high resolution. The pattern accuracy can be improved.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Manami Fukuda             1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture             Within Fujitsu Limited

Claims (4)

[Claims] 1. A resist composition (Si ₂ R ¹ O ₃ ) _m (R ² ₃ SiO _1/2 ) _n, containing an organic silicon polymer represented by the following general formula (1) as a main component. - (1) thisゝa, R ¹ represents an alkylene, R ² represents a monovalent hydrocarbon group and may be the same or different. m and n are positive integers, 2. A polymer obtained by hydrolyzing an organosilicon compound represented by the following general formula (2) and dehydration polycondensation to obtain one of the following general formulas (3), (4) and (5): The organic silicon polymer according to the above general formula (1), characterized in that the hydroxyl group in the polymer is replaced with a triorganosilyl group represented by the following general formula (6). Manufacturing method. X ₃ SiR ¹ SiX ₃・ ・ ・ ・ ・ ・ (2) R ² ₃ SiX ・ ・ ・ ・ ・ ・ (3) R ² ₃ Si-NH-SiR ² ₃・ ・ ・ ・ ・ ・ ・ ・(4) R ² ₃ Si-O-SiR ² ₃・ ・ ・ ・ ・ ・ (5) R ² ₃ Si- ・ ・ ・ ・ ・ ・ (6) Here, X is a halogen group or alkoxy. Group, cyano group, isocyanato group or isothiocyanato group, R ¹ represents alkylene, R ² represents a monovalent hydrocarbon group, which may be the same or different. 3. At least one of the silicon compounds represented by the following general formulas (3), (4) and (5) is dissolved in an organic solvent, and this solution is dissolved in the presence of water to give the following general formula (2): ) The organic silicon compound represented by the formula (1) is gradually added to cause dehydration polycondensation, and the hydroxyl group contained in the organic silicon compound is replaced with a triorganosilyl group represented by the following general formula (6). A method for producing the organic silicon polymer represented by the general formula (1). X ₃ SiR ¹ SiX ₃・ ・ ・ ・ ・ ・ (2) R ² ₃ SiX ・ ・ ・ ・ ・ ・ (3) R ² ₃ Si-NH-SiR ² ₃・ ・ ・ ・ ・ ・ ・ ・(4) R ² ₃ Si-O-SiR ² ₃・ ・ ・ ・ ・ ・ (5) R ² ₃ Si- ・ ・ ・ ・ ・ ・ (6) Here, X is a halogen group or alkoxy. Group, cyano group, isocyanato group or isocyanato group, R ¹ represents alkylene, R ² represents a monovalent hydrocarbon group, which may be the same or different. 4. At least one of the silicon compounds represented by the following general formulas (3), (4) and (5) is dissolved in an organic solvent, and the solution of the following general formula (2 ) The organic silicon compound represented by the formula (1) is gradually dehydrated and polycondensed, and the hydroxyl group contained in the organic silicon compound is replaced with a triorganosilyl group represented by the following general formula (6). (3),
A method for producing an organic silicon polymer described in the above general formula (1), characterized by adding a silicon compound represented by (4) or (5). X ₃ SiR ¹ SiX ₃・ ・ ・ ・ ・ ・ (2) R ² ₃ SiX ・ ・ ・ ・ ・ ・ (3) R ² ₃ Si-NH-SiR ² ₃・ ・ ・ ・ ・ ・ ・ ・(4) R ² ₃ Si-O-SiR ² ₃・ ・ ・ ・ ・ ・ (5) R ² ₃ Si- ・ ・ ・ ・ ・ ・ (6) Here, X is a halogen group or alkoxy. Group, cyano group, isocyanato group or isocyanato group, R ¹ represents alkylene, R ² represents a monovalent hydrocarbon group, which may be the same or different.