JPS62220949A - Photoresist material and photosensitive resin composition - Google Patents

Abstract

PURPOSE:To obtain unswellable negative photoresist capable of being developed with alkali by constituting the resist of a specified constitution having a principal chain of a polymer consisting of polysiloxane structure. CONSTITUTION:The photoresist material is expressed by the formula, namely, a silicone polymer having enhanced O2RIE resistance by adopting polysiloxane structure and having elevated glass transition temp. (Tg) by introducing many phenyl groups into the side chain. In the formula, R', R'', and R''' are same or different groups, being at least one selected from H, alkyl, and phenyl. l, m, and n are zero or a positive integer, wherein l and m can not be zero simultaneously. Since a hydrophilic group such as COOH group introduced into a phenyl group causes a crosslinking reaction by the irradiation with high energy rays, the polymer becomes insoluble in alkaline developing soln. Swelling of the polymer is not caused also. On one hand, the part of the polymer which is not irradiated is held in the condition soluble in the alkaline developing soln. Accordingly, the photoresist material is a negative type one capable of being developed with alkali.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a resist material for high-energy rays that reproduces negative patterns with high precision and has high resistance to oxygen plasma, and that produces positive patterns with high precision against ultraviolet rays. This invention relates to a photosensitive resin composition that can be reproduced.

[Prior art and its problems]

Conventionally, resist materials for high-energy radiation have been used for pattern formation in LSI processing processes. Among these, fluorine-containing methacrylate polymer is known to have high sensitivity (1×10'C/dll>) as a positive resist (Patent No. 1034536).However, this highly sensitive positive resist It has the disadvantage of low plasma processing resistance in LSI processing.In contrast, chloromethylated borisdyrene (CMS), which is a negative resist, is known as a resist with high sensitivity and high plasma processing resistance (Patent No. 1107695). )
. However, with this negative resist, the resolution decreases as the film thickness increases, making it impossible to form fine patterns. Therefore, in order to solve this drawback, by using a multilayer resist instead of a single layer, the film thickness can be increased.
Moreover, methods have been proposed for forming fine patterns with high shape ratios. That is, after forming a thin film of resist material on the first Wa, high energy is irradiated non-stop to the resist material of the second layer, and the organic polymer of the first layer is subjected to oxygen plasma etching (O2 plasma etching) using the pattern obtained after development as a mask.
The aim is to obtain a pattern with a high shape ratio by anisotropic etching with zRIE (8.J, Li
n 5olid 5tate Technol, 24
73 (1981)), in this method 02RIE
Since the resistance must be high, it has been proposed to use Si polymer as this resist material. For example, 1latzakis et al. used polyvinylmethylsiloxane polymer as a negative resist to form patterns (H, 1latzakis et al.
oc, Int' 1. Conf, Hicrolith
(1981)).

However, this negative molding material has a problem in that it has a low glass transition temperature (TO). If TO is low, dust tends to adhere to the resist, wA thickness sub-control is difficult,
This is because the problem of deterioration in developability due to pattern deformation during development occurs.

As described above, the resist material needs to have a high To and also a high resistance to 02RIE.

Furthermore, in order to form a high-resolution pattern, an alkaline development type non-swelling resist is required.

[Means for solving problems]

Therefore, in this invention, the above-mentioned problems are solved by using a silicone polymer that has a polysiloxane structure to improve 02RIE resistance and also has a large number of phenyl groups introduced into the side chain to increase TQ. did.

To summarize the present invention, the first and second inventions of the present invention relate to resist materials, and are represented by the following general formula (I> or (II) [However, in the general formulas 1 and 2, X is R-C- , R-CH-00)-1 (R represents a hydrocarbon or substituted hydrocarbon), and a carboxyl group, and may be the same or different.

1, and RJJ and R″′ are the same or different and represent one type of group selected from the group consisting of hydrogen, an alkyl group, and a phenyl group.

J, m and n represent O or a positive integer, and 1 and m cannot be 0 at the same time. ] It is characterized by being expressed as.

Since the resist material of the present invention has a polysiloxane structure as the main chain of the polymer, it has very high resistance to 02RIE and is advantageous for forming a fine pattern with a high aspect ratio. Furthermore, despite having a polysiloxane structure, there are many phenyl groups in the side chains, so the TO value is above room temperature and can be used as a resist. Furthermore, R-C-, R-C)l- to the phenyl group.

The polymer is soluble in an alkaline aqueous solution because it has a hydrophilic group such as a carboxyl group introduced therein. Therefore, it has the characteristic that it can be used as a non-swellable resist that can be developed with an alkali.

However, since hydrophilic groups such as carboxyl groups introduced into phenyl groups undergo a crosslinking reaction when irradiated with high-energy rays, the polymer becomes insoluble in an alkaline developer and does not swell. On the other hand, the non-irradiated areas remain soluble in an alkaline developer, and the resist material according to the present invention can be said to be a negative type that can be developed with an alkali.

The larger J and m in general formulas (I) and (II), the higher the reactivity to high energy rays and the higher the sensitivity, but if they are too large, the SL content will decrease and 02RIE
Resistance decreases. For this reason, 2J+m/! +m+n is 0.
A nodal frequency of 1 to 1.5 is preferred.

Next, the third and fourth inventions of the present invention relate to a photosensitive resin composition, which has the general formula (1).

(n) and the following general formula (I[[)
Represents one type of group selected from the group consisting of C2H5. ) is characterized in that it includes an eltonaphthoquinone compound.

Although it has been mentioned that the resist 44 is alkali-soluble, it can therefore be used as a positive photosensitive resin composition by adding the above-mentioned orthonaphthoquinone compound. In other words, a photosensitive resin composition in which an orthonaphthoquinone compound represented by general formula (III) is added to an SL-containing polymer represented by general formula (I> or general formula (n)) is irradiated with ultraviolet rays (LIV). The orthonaphthoquinone compound becomes the corresponding indene carboxylic acid and the irradiated area is removed by alkaline development, so it exhibits positive resist characteristics.

In this photosensitive resin composition, the orthonaphthoquinone compound serves as an agent for preventing dissolution of the resist in an alkaline solution. The amount of the orthonaphthoquinone compound added is usually in the range of 5 to 30% by weight. If it is less than 5% by weight, it will not be possible to suppress the dissolution of the polymer compound in an alkaline developer and alkaline development will not be possible, and if it exceeds 30% by weight, the Si content as a resist material will decrease and oxygen plasma resistance will be reduced. It decreases and causes inconvenience.

Generally, a preferable addition amount is about 10% by weight.

tJ of the siloxane polymer represented by the general formula l of the present invention
& method: hexaphenylcyclotrisiloxane,
There is a method of ring-opening polymerization of a cyclic phenyldioxane such as octaphenylcyclotetrasiloxane with an alkali metal hydroxide such as potassium hydroxide or an alkylated alkali metal such as butyl lithium, and modifying the resulting polydiphenylsiloxane. .

Further, instead of using cyclic phenylsiloxane alone, it may be copolymerized with tetramethyltetraphenylcyclotetrasiloxane, octamethylcyclotetrasiloxane, or the like. In addition, especially when it is desired to form a high-resolution pattern, a monodisperse polymer with uniform molecular ω is preferable, but cyclosiloxane can be subjected to anionic living polymerization with a catalyst such as butyllithium, and the resulting polymer can be modified. A desired monodisperse polymer can be obtained by this method.

As a method for producing the phenylsilsesquioxane polymer represented by the general formula (2) of the present invention, the phenylsilsesquioxane polymer easily obtained by hydrolyzing a silane compound represented by (]-5LZ3 (Z is C! or 0C113) There are ways to modify oxane polymers.

Next, a method for forming a pattern using the photosensitive resin composition of the present invention will be explained.

First, a film of an organic polymer material is formed on a substrate such as silicon, and the photosensitive resin composition of the present invention is applied thereon to form a two-layer structure. Then, after heat treatment, light is irradiated to make only the irradiated area soluble in a developing solvent, and then the photosensitive resin composition in the irradiated area is removed by development. Next, using the non-irradiated portions of the photosensitive resin composition as a mask, a pattern is formed by dry etching using oxygen gas to remove the underlying organic polymer material. The above-mentioned organic polymer material may be any material as long as it can be etched by oxygen plasma, but aromatic-containing polymers are preferred in order to increase resistance when dry etching the substrate using this as a mask after pattern formation. .

Production examples will be shown below, but the present invention is not limited thereto.

(Manufacturing Example 1) Add 15 g of anhydrous aluminum chloride and 5 g of acetyl chloride to a 300 d flask equipped with a stirrer and a thermometer.
Take 0I11 and stir. Next, 5q of polyphenylsilsesquioxane with a molecular weight of 7800 was added to 50M of acetyl chloride.
Gradually add the solution dissolved in No. 1 dropwise. The reaction is allowed to proceed while maintaining the temperature at 25°C. Hydrogen chloride is generated as the reaction progresses. After reacting for 3 hours, the mixture was cooled and the contents were poured into ice water containing hydrochloric acid. Stir well to decompose the aluminum chloride, and after confirming that the ice water is acidic, separate the precipitated polymer by furnace. Wash thoroughly with dilute hydrochloric acid and water. Finally, dry it in a vacuum dryer. The molecular weight of the obtained polymer was 7,900.

In the infrared absorption spectrum, carbonyl group absorption was observed at 167 Ocm', and in NMR, methyl group absorption was observed at 2°4, confirming acetylation. The acetylation rate at this time was 60% based on NMR.

(¥J Preparation Example 2) Add 25 m of stannic chloride and 50 m of acetic anhydride to a 300 d flask equipped with a stirrer and a thermometer and a leak-tight door and stir. Next, a solution of diphenylsilanediol 6Q dissolved in 50 ml of acetic anhydride is gradually added dropwise. Production example 1 below
Acetylated polysiloxane was obtained in the same manner as above. The molecular weight of the obtained polymer was 1500, and the acetylation rate was 42%.

(Production Example 3) Acetylated polyphenylsilsesquioxane 6Q obtained in Production Example 1 was dissolved in a 10% aqueous solution of sodium hypochlorite.
Add to 0IR1 and reflux for 12 hours.

When the resulting clear liquid is made acidic by adding hydrochloric acid, a precipitate forms. A yellowish white solid was obtained by separating each unit. In the infrared absorption spectrum, the absorption of the carbonyl group at 1670aR-' disappeared and the absorption of the carboxyl group was observed at 1700cm-', indicating that it was carboxylated. Yield: 70% (Production Example 4) The acetylated polydiphenylsiloxane 6Q obtained in Production Example 2 was dissolved in a 10% aqueous solution of sodium hypochlorite.
d and reflux for 12 hours. Thereafter, carboxylation was carried out in the same manner as in Production Example 3. Yield: 65% The carboxylated products obtained in Production Examples 3 and 4 were soluble in alkaline aqueous solutions, methanol, and ethanol, but insoluble in other organic solvents.

(Production Example 5) The acetylated polyphenylsilsesquioxane 5Q obtained in Production Example 1 was dissolved in tetrahydrofuran 10011r1, 3 g of Li#lIs was added thereto, and rapid flow was performed for 3 hours. After the reaction is complete, pour into ice water containing 5% hydrochloric acid,
A yellowish white solid was obtained. In the infrared absorption spectrum of the product with a yield of 55%, the carbonyl absorption at 1670cII-' observed in the raw material disappeared, and absorption due to the OH group was observed around 3100-3400CIR-', confirming that it had been reduced. Ta.

(yJ Preparation Example 6) Acetylated polydiphenylsiloxane 5 obtained in Production Example 2
Dissolve g in 100-g of tetrahydrofuran and add 30
of LiA#t14 was added and refluxed.

After the reaction was completed, the mixture was poured into ice water containing 5% hydrochloric acid to obtain a yellowish white solid. Yield: 66% The polymers obtained in Production Examples 5 and 6 were soluble in alkaline aqueous solutions and alcohols such as methanol.

(Production Example 7) In Production Example 1, acetylated polydiphenylsiloxane was prepared by using the same method as polydiphenylsiloxane (molecular ff: 110,000) obtained by ring-opening polymerization of cyclic siloxane instead of polyphenylsilsesquioxane. is.

(vJ Preparation Example 8) Brobionylated polyphenylsilsesquioxane was prepared by the same method as in Preparation Example 1, using buO-pionyl chloride instead of acetyl chloride.

('#J Preparation Example 9) A propionylated polyphenylsiloxane was obtained in the same manner as in Preparation Example 7 using propionyl chloride instead of acedel chloride.

〔Example〕

(Example 1) Ethyl cellosolve solutions of the resist materials obtained in Production Examples 1 to 9 were applied to a silicon wafer to a thickness of about 0.2 μm by a spin code method, and prebaked at 80° C. for 20 minutes. After prebaking, high energy rays (N radiation, X-rays, far ultraviolet rays) were irradiated.

After irradiation, Microposit 2401 (manufactured by Sibley)
The film was developed with a developer having a ratio of 171 to 171, and the sensitivity was defined as the irradiation m at which the rAwA of the irradiated area became 50% of the initial film thickness.

The resolution was determined by measuring the minimum pattern size that can be resolved in a line and space pattern.

Table 1 shows the sensitivity and resolution.

(Example 2) A photosensitive resin composition in which 20% by weight of a naphthoquinone compound represented by Vt was added to the resist material of Production Examples 1 to 9 was applied to a silicon wafer to a thickness of about 0.2 μm.
Prebaked at 0°C for 20 minutes. After prebaking, it was irradiated with ultraviolet light using an Oak jet light. After irradiation, the film was developed with the same developer as in Example 1, and the sensitivity was defined as rJJffl at which the remaining film in the irradiated area was O.

Table 2 shows the sensitivity and resolution. Resolution was evaluated by forming line and space patterns, and each material was 0.5 μm.
A wide pattern was formed.

(Example 3) Using the phenylsiloxane polymer according to Production Example 1, 3
3, and group 2 has the following structure: (+) -0H1 (2)
-0C1, (3) -OF, C2H5 was added in an amount of 20% by weight, and the sensitivity to ultraviolet light (irradiation a) was measured in the same manner as in Example 2.

The results are summarized in Table 3.

(Example 4) AZ-1350 resist (manufactured by Sibley) was coated on a silicon wafer to a thickness of 2 μm, and heated at 200° C. for 30 minutes to make it insolubilized. The resist material used in Example 2 was applied on top of this AZ resist in the same manner as in Example 2 to a thickness of about 0.2 μm.
It was coated to a thickness of m and prebaked at 80° C. for 20 minutes.

After prebaking, ultraviolet rays were irradiated through a chrome mask with a 0.5 μm line and space pattern.
When development was performed with a developer having the same composition as , the pattern of the mask was transferred to the ΔZ resist abrasive material. (U, AZ using a parallel plate type sputter etching equipment with oxygen gas as etch 1~1 gas and resist pattern as mask)
Etched the resist.

By etching for 15 minutes under the conditions of RF power of 0.2 W/ci and O2 gas pressure of 20 mTorr, the AZ resist in the portions not covered by the resist pattern completely disappeared.

0°5 μm for any resist material used in Example 2
A line and space pattern with a thickness of about 2 μm could be formed.

〔Effect of the invention〕

As explained above, the resist material of the present invention is an alkali-soluble siloxane polymer, and since it is crosslinked by high-energy ray irradiation, it becomes an alkali-developable non-swellable negative resist.

Furthermore, since it contains silicon, it has high resistance to oxygen plasma, and therefore can be used as an upper layer resist of a two-layer resist.

On the other hand, a photosensitive resin composition obtained by adding an orthonaphthoquinone compound to the above resist material becomes a positive photoresist that is highly sensitive to ultraviolet light.

All of them can be developed with alkali and can be used in two-layer resists, so they have the advantage of being able to form fine patterns of 0.5 μm or more with a high aspect ratio of 7, which was not possible with conventional resist materials.

Claims (4)

[Claims] (1) The following general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [However, X is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ) is a type selected from the group of carboxyl groups, and may be the same or different. R′, R″ and R″′ are the same or different, hydrogen,
1 selected from the group consisting of an alkyl group and a phenyl group
Indicates the group of species. l, m and n represent 0 or a positive integer, and l and m are never 0 at the same time. ] A resist material characterized by the following. (2) The following general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [However, X is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ) is a type selected from the group of carboxyl groups, and may be the same or different. R′, R″ and R″′ are the same or different, hydrogen,
1 selected from the group consisting of an alkyl group and a phenyl group
Indicates the group of species. l, m and n represent 0 or a positive integer, and 0 and m are never 0 at the same time. ] A resist material characterized by the following. (3) The following general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [However, X is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ) is a type selected from the group of carboxyl groups, and may be the same or different. R′, R″ and R″′ are the same or different, hydrogen,
1 selected from the group consisting of an alkyl group and a phenyl group
Indicates the group of species. l, m and n represent 0 or a positive integer, and l and m are never 0 at the same time. ] Resist material represented by the following general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, Z is -OH, -OCl, -OF, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas) There are , tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas,
There are tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas,
There are tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and ▲There are mathematical formulas, chemical formulas, tables, etc.▼ Indicates one type of group selected from the group consisting of. ) A photosensitive resin composition comprising an orthonaphthoquinone compound represented by: (4) The following general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [However, X is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ) is a type selected from the group of carboxyl groups, and may be the same or different. R′, R″ and R″′ are the same or different, hydrogen,
1 selected from the group consisting of an alkyl group and a phenyl group
Indicates the group of species. l, m and n represent 0 or a positive integer, and l and m are never 0 at the same time. ] Resist material represented by the following general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, Z is -OH, -OCl, -OF, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas) There are , tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas,
There are tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas,
There are tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and ▲There are mathematical formulas, chemical formulas, tables, etc.▼, Indicates one type of group selected from the group consisting of. ) A photosensitive resin composition comprising an orthonaphthoquinone compound represented by: