JPS6235345A - Photosensitive composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a photosensitive composition that provides a positive pattern by development after irradiation with light, and particularly relates to a photosensitive composition that provides a positive pattern by development after irradiation with light, and particularly relates to a photosensitive composition that provides a positive pattern when developed after irradiation with light, and in particular, it relates to a photosensitive composition that provides a positive pattern when developed after irradiation with light. The present invention relates to a photosensitive composition suitable as an oxygen plasma resistant film when an organic planarization layer is etched by oxidation plasma.

[Background of the invention]

2. Description of the Related Art In the production of electronic components such as semiconductor elements and integrated circuits, micro-etching techniques using etching using radiation and radiation are used. As resist materials used in this case, alkali-developable photosensitive compositions consisting of an alkali-soluble polymer such as a phenol resin and a photosensitizer are mainly used because of their excellent resolution. - With the miniaturization of wiring in semiconductor devices, etc., dry etching is increasingly being adopted in place of wet etching for etching the underlying layer after patterning the resist layer. Therefore, resist materials are required to have strong resistance to dry etching.

For example, if the underlying material is an organic material (such as an organic insulator or an organic flattening layer in a two-layer resist method), it is etched using oxygen plasma, but conventional alkali-developed resist materials have poor resistance to oxygen plasma, and their properties cannot be improved. It was strongly desired.

In addition, the literature on alkali-developable photosensitive compositions is as follows:
Written by John Strieta: Hudatsuk Microelectronics - Seminar Presentation (J,
C,5trieter:Kodak Microe
lectro-n1cs Sem1nor Proc
edings), z6+ (1976), etc.

[Purpose of the invention]

An object of the present invention is to provide an alkaline active type element-sensitive composition having excellent oxygen plasma resistance, which can be replaced with the above-mentioned conventional alkaline active type element-sensitive compositions having low oxygen plasma resistance.

[Summary of the invention]

In order to increase the oxygen plasma resistance of the photosensitive composition, it is most effective to increase the oxygen plasma resistance of the basic polymer based on its weight range. Organosilicon polymers are known as polymers with excellent oxygen plasma resistance.

This is because organosilicon polymers efficiently turn into a silicon oxide film when exposed to oxygen plasma, and this silicon oxide film acts as an oxygen plasma-resistant film.On the other hand, as an alkali-soluble polymer, there are Polymers having phenolic hydroxyl groups are known.Therefore, the present inventors aimed to obtain a polymer that is alkali soluble and has excellent oxygen plasma resistance.
As a result of synthesizing various polymers having a phenolic hydroxyl group in the side chain, it was discovered that a polymer represented by the following general formula (11) satisfies the above objectives.

Here, the general formula (11, 8, Tame, and Tori are monovalent a)
! The group includes, for example, hydrogen, an alkyl group, a vinyl group, an aromatic group, and their derivatives, but a C1-C6 alkyl group is preferable for animals and birds, and hydrogen is preferable for birds. In addition, ``Tori'' indicates a C1 to C6 alkyl group, and the number of OH and OR groups is 1 or 2, and may be located at any position on the benzene ring. Also, m and n
is an integer, m1n is 2 to 200, and n/(m10n) needs to be 0.4 or more in order to be alkali soluble.

This superimposed body is soluble in alkaline water, such as an aqueous solution of tetramethylammonium hydroxide, and is quenchable. In addition, general-purpose organic solvents such as alecole ether type, amide type, etc.
It is easily soluble in organic solvents such as ketones and ester A selenium-based solvents2.Also, this polymer exhibits extremely high dry-etching resistance without smearing in oxygen plasma. It can be synthesized by various methods, and is not particularly regulated by synthetic methods.

On the other hand, the role of the two-sensitizing agent in an alkali-developable photosensitive composition is to act as an alkali dissolution inhibitor for the alkali-soluble polymer in the unexposed area, and to act as an alkali dissolution inhibitor for the alkali-soluble polymer in the exposed area. It changes into a bath-prone compound and makes the exposed area alkali-prone. As such a photosensitizer, 1,2-naphthoquinonediazide sulfonic acid esters represented by the following general formula (2) are well known, and the alkali-developable photosensitive group of the present invention can also be used as a photosensitizer. It can be used as

;, Here, in general formula (2), crow represents a monovalent organic group. -80. -R6 group position is 1,2
- It is the 4th or 5th position of naphthoquinone diazide. R
, (--o So, -R, when the group position is at the 5th position)
Examples include the following groups.

Next, a method will be described in which the photosensitive composition containing the alkali-soluble silmethylene polymer and a photosensitizer is used to form a pattern of a semiconductor element or the like.

Polymers 70 to 9 containing 70 to 100 units by weight of the alkali-soluble cytimethylene polymer represented by the general formula (1)
5 parts by weight (50 to 0 parts by weight of the alkali-soluble cytimethylene polymer represented by general formula (1), according to a recipe known per se, well-known compounding agents, such as a film forming agent such as novolac resin) (Can be mixed within a range.)
and a photosensitive agent in which the film of the composition with the above polymer is alkali-insoluble before light irradiation but becomes alkali-soluble upon light irradiation, for example, a photosensitizer represented by general formula (2) 30 to 5% by weight A photosensitive composition consisting of the The film is spin-coated and prebaked under appropriate temperature conditions to obtain a film using the photosensitive composition of the present invention. Next, a desired pattern is irradiated with the original, and the irradiated areas are selectively dissolved using an alkaline reaction solution such as an aqueous tetramethylammonium hydroxide solution to obtain a positive resist pattern. Furthermore, when processing the underlying organic material, a pattern with a high aspect ratio can be formed by dry etching the underlying organic material using oxygen plasma or the like using the resist pattern as a mask.

[Embodiments of the invention]

The present invention will be explained below using specific synthesis examples and examples, but the present invention is not limited thereto.

Synthesis Example 1 Poly(1,1-dimethyl-2-P-methoxyphenylsilmethylene-Co-1,1-dimethyl-2-P
-Hydroxyphenylsylmethylene) 1.1 Synthesis of chloromethyl-P-methquine benzylsilane
In a three-necked flask, add 3 tog (t2s) of magnesium powder.
moz), dimethyldichlorosilane 129 g (l
m ot ) and diethyl-1-thyl 500 m
/ is inserted. After cooling the flask below vto'C,
P-methoxybenzyl chloride toog (0
, 659mot) and diethyl ether 250rrB was added dropwise over 4 hours. After aging for a further hour at room temperature, excess magnesium and magnesium chloride are removed by suction filtration. By distilling the p-liquid, 87.8 g (0,409 mo/) of the target product was obtained. Yield 64. .

boiling point 80°C/1 mHg%NMRx hector (6°M) lz, CCt4. CH, Ct, δ5.
55) δ0.46 (6H,S)2.4o(2H,S)
, 3.83(3H,,S), h82<2H.

d, J-9,0Hz), 7. Q 8 (2H, d
, J-9,0)1z)IR Speari)/I
/(V'l-') 2971L 1 62
0°1520, 1475. 1310. 12150
．． 1195.1090°1055, 855. 82
5. 780゜1, 2.7" Synthesis of chlorodimethyl-P-methquinbenylchlorodimethylsilylmethane (dz) In a 500 ml three-necked flask equipped with a stirrer and a reflux tube, 43% of chlorodimethyl-P-methquinbenzylsilane was added.
．． Add 2g (0.2oOmoz) and 200ml of carbon tetrachloride. While heating and stirring carbon tetrachloride, 55.6 g of N-bromosuccinimide (0.2G Omol
) gradually.

After aging for 1 hour, the succinic acid imide was removed through a suction port, and the liquid was distilled to obtain st7g (st7g) of the target product.
108 mol) was obtained. Yield 54.0%, boiling point 113-1
17°C/2.5 Tsuru Hg, melting point 30°cH, NMR
Spect/I/(+SOMH2゜CCz,,TMS)δ
0.50(3)1.8), 0.60(3H,S
), 5.75 ('5H,S), 4.32 (1H1S
), 6.7 5 (2H, d, J-9Hz),
7.19 (2H, d, J-9Hz), Engineering R spectrum (VC beak-vine) 16+0. 1510.
1465°1505, 1260. 1+85.
1040°865, 845. 820. 800°1
．． 3 Synthesis of poly(1,1-dimethyl-2-P-methoxyphenylsilmethylene) A three-hole flask equipped with a Herschberg stirrer, a reflux tube, and a dropping funnel was purged with nitrogen. 7.6 g of sodium in the flask (0.33 gato
n) and 120 m/m of toluene were added and stirred with heat under the knife to obtain fine particles of sodium. While stirring the toluene under reflux, a mixture of 44.1 g (0.15 mot) of promo P-methoxyphenylchlorodimethylsilylmethane and 30 m/toluene was added dropwise over 1 hour. After subsequent aging for 1 hour, the reaction mixture is poured into methanol to remove excess sodium and to precipitate the polymer. After filtration, the sodium salt was removed by dropping the polymer dissolved in tetrahydrofuran in water (10 g of the target product was obtained by washing the filtered polymer with methanol and drying under reduced pressure. Yield: 37, softening point: 121 ~125QC
, weight average molecule [4400, N~I 11. Spectrum (60MHz, C, Do, CH, Ct, δ5.33)
δt 27 (6H, br, s), 4.43 (
3Hebr.

S) 7.4~8.7 (4H,br,S)
, methine proton is difficult to confirm, IR spectrum (V"'
)2960.2850,1610.1510゜1470
．． 1385.1300, 1260°1100.1045
．． 860,1790゜1.4 Poly(1,1-dimethyl-2-P-methoxyphenylsilmethylene-〇〇-11
-Dimethyl-2-P-hydroxyphenylsylmethylene) Synthesis of Me HMe
P-methoxyphenylsilmethylene) 0.50 g (
2.8 mmoz in monomer units) and chloroform tsmz
and 0.88 g (4,4 m
Add mo/) and stir with a magnetic rod. After reacting for 4 hours, 4 ml of methanol was added and stirred for 3 hours.

Low boilers were distilled off under reduced pressure at room temperature, and the residue was extracted with ether. The ether solution is washed with an aqueous sodium bisulfite solution, an aqueous solution of hydrogen carbonate, and brine, and the ether is distilled off under reduced pressure. The obtained polymer was reprecipitated with tetrahydrofuran/water and dried under reduced pressure with heat to remove the target product.
．． 23g was obtained. Weight average molecular weight 1.800, OH content t1
00 coefficient, softening point 107-113°C, N-IR spectrum (60MHz1 DM80-d, δ5.68)
δ-0,79~0.5 1 (6H, br,
s), &1 5-7.3 5 (4H, br, s),
Methine proton, hydroxy proton difficult to identify, IR spectrum (vca) 3380.2980, 1510.1
270°1100.1040,860.810 The OH content can be controlled by the amount of trimethylsilyl iodide or reaction time. For example, when a methoxy group is reacted with 13 equivalents of trimethylsilyl iodide for a reaction time of 4 hours, the methoxy group is converted to a 90-functional hydroxyl group.

Also, 0.80 equivalent is 70, α65 equivalent is 55, 0
．． The conversion rate was 40 for 50 children. The value of OH content was determined by conducting the reaction in deuterated chloroform and monitoring the process of converting methoxy groups into trimethylsiloxy groups using NMR spectroscopy.

As a result of investigating the solubility of poly(1,1-dimethyl-2-P-methoxyphenylsylmethylene-Co-1,1-dimethyl-2-P-hydroxyphenylsylmethylene) in a typical general-purpose organic solvent, OH This polymer with a content of 40 or more was soluble in methanol, tetrahydrofuran, NN-dimethylacetamide, 2-methylcyclohexanone, isoamyl acetate, methyl cellosolve, and dimethyl sulfoxide, but insoluble in toluene, hexane, and carbon tetrachloride. . On the other hand, in the aqueous solution, it was dissolved in an aqueous tetramethylammonium hydroxide solution.

The oxygen glaze resistance was investigated as follows. That is, BoIJ (1,1-dimethyl-2-P-methoxyphenylsilmethylene-C0-11-dimethyl-2-
P-hydroxyphenylsylmethylene)
-Methylcyclohexanone solution was applied onto a silicon substrate by a spin-eating method and baked at 100°C for 30 minutes (to form a polymer coating film with a thickness of 1.2 μm).

Next, oxygen plasma (conditions: O2 pressure CL5 torr)
% RF 300W, barrel-type asher for 20 minutes, the polymer did not peel off.

Example 1 70 parts by weight of the polymer obtained in Synthesis Example 1 (weight average molecular weight: 23,000H content: 86 parts) and 30 parts by weight of the following photosensitizer were dissolved in ethyl cellosolve, and 8 parts by weight were used as a width solution. This solution was applied to 7 recon wafers for 200 Or
Spin coat at 75 °C for 30 s at p, m.
A film with a thickness of 0.2 μm was formed by prebaking for 1 minute. This was then energized at 500W through an emulsion mask.
Irradiation was performed using a xenon-mercury lamp (irradiation intensity: 11 mW/aj at 565 nm). After light irradiation, add 2 to 3.3 tetramethylammonium hydroxide aqueous solution (25'C).
After immersion for 0 seconds and development, the irradiated area was solubilized by rinsing with water to obtain a positive pattern. As a result, it was exposed to light at 290 to 460 nm, had a sensitivity of 80 m J/cd at 365 nm, had a γ value of 9, and was able to resolve a 0.5 μm line by contact exposure.

Example 2 Polymer obtained in Synthesis Example 1 (weight average molecular weight 2.3000H
80 parts by weight of an alkali-soluble polymer consisting of 70 parts by weight (content 86%) and 30 parts by weight of cresol novolak resin.
1. After dissolving 20% by weight of the same photosensitizer as in Example 1 in ethyl cellosolve to make an 8% by weight solution, a film with a thickness of 12 μm was formed in the same manner as in Example 1, and the 8-component material was irradiated with light. After irradiation, an aqueous solution of detramethylammonium hydroxide (
A positive tone pattern was obtained by immersion at 23° C. for 30 seconds, development and rinsing with water.

As a result, the sensitivity at 365 nm was 80 mJ/
cj.

The γ value was 7, and a line of 15 μm could be resolved with the close i-element.

Example 6 Polymer obtained in Synthesis Example 1 (weight average molecule -@2.511
Q.

0H content 864) 95 weight and the following photosensitizer 5m-t
%'&ethyl selonorp and 8 weight was made into a width solution, and then a 0.2 μm thick film was formed in the same manner as in Example 1 and irradiated with light. After irradiation with light, the sample was immersed in a 3.0% aqueous solution of tetramethylammonium hydroxide (22°C) for 30 seconds (Jl) and rinsed with water to obtain a positive pattern.

As a result, it is exposed to light from 275 to 460 nm, and 565 nm
The sensitivity was 100 mJ with nm light, the γ value was 4, and a line of α 5 μm could be resolved by contact exposure.

Example 4 Polymer obtained in Synthesis Example 1 (weight average molecular t 2.30 skin O
After dissolving H content (86%) and 90% by weight of the following photosensitizer in ethyl cellosolve and using 8% as a solution, a film with a thickness of α2 μm was formed in the same manner as in Example 1, and irradiated with light. did. After irradiation with light, the film was developed by immersing it in a 3.3mm aqueous solution of tetramethylammonium hydroxide (25°C) for 20 seconds, and rinsing with water to obtain a positive pattern. As a result, it was found to be sensitive to light of 290 to 460 nm, with a sensitivity of 65 mJ/cd and a γ value of 7 at 365 nm.

In addition, 27 Tetramethylammonium hydroxide aqueous solution 1
When developed for 30 seconds in a developer (24°C) containing ethyl cellosolve 2.4 mz to oomt, the sensitivity was 50 m.
J/=j, and the γ value was 5.

In addition, even if a developing solution is used, 0.5
It was possible to resolve lines of μm.

Example 5 Polymer obtained in Synthesis Example 1 (heavy charge average molecular weight 2300°OH
Content 86'1) 90% by weight and 10% by weight of the same photosensitizer as in Example 4 were dissolved in ethyl cellosolve, and 16% by weight was obtained.
It was made into a solution. 1. Apply this solution onto a silicon wafer. OO
Spin coat with Or-Emm for 50 seconds, 75'
A film with a thickness of 1.8 μm was formed by prebaking at C for 30 minutes.

Next, after light irradiation in the same manner as in Example 1, a 53-functional tetramethylammonium hydroxide aqueous solution (25°C) or a 2.74-functional tetramethylammonium hydroxide aqueous solution ff
2.4 ml of ethyl cellosolve per 100 m/i
A positive pattern was obtained by immersing the sample in a developer solution (25°C) for 2 minutes and rinsing with water. As a result, no matter which developer was used, the sensitivity was 7 at 365 nm.
5mJ/cd.

The γ value was 4, and a line of 1 μm could be resolved by contact exposure.

Example 6 IQ (manufactured by Hitachi Chemical) of 3.0 on a silicon wafer
Spin coat for 1 minute at 1 m, then 200°
A PIQ film with a thickness of 2.0 μm was formed by baking at C for 130 minutes and then at 350° C. for 130 minutes. Next, under the same conditions as in Example 5, 11.2μ of the photosensitive composition was prepared.
A film with a thickness of m was formed and irradiated with light. After light irradiation, diluted with aqueous solution of tetramethylammonium hydroxide (24°C) for 20 hours.
Developed for seconds to obtain a positive pattern. The sensitivity at that time is 3
1 s o m J/cd at 65 nm, and the γ value was 25. In addition, add 2.711 ethyl cellosolve to 100 mj of aqueous tetramethylammonium hydroxide solution.
When developed for 30 seconds with a developer solution (24°C) containing 4 mt'l, the sensitivity was 95 mJ/cd and the r value was 3.5.
Met. In addition, with any developer, 0.
A pattern of 5 μm could be resolved.

Next, oxygen plasma etching (etching conditions:
When PIQ was etched for about 20 minutes using R, ["200 W, O, pressure 3 mTorr + cathode bias voltage -120 to -joOV, parallel plate type], a 0.5 μm #J width PIQ fine pattern with an aspect ratio of 4 was formed. Example 7 A film of 2.0 μm was deposited on a silicon wafer under the same conditions as Example 6.
A PIQ film with a thickness of m was formed, and then a film of a photosensitive composition with a thickness of 18 μm was formed on the PIQ under the same conditions as in Example 5. Next, after light irradiation in the same manner as in Example 1, 2.4 m/2.4 m of ethyl cellosolve was added to 100 m/2.74 tetramethylammonium hydroxide aqueous solution (25°C) or 2.74 tetramethylammonium hydroxide aqueous solution (25°C). A positive pattern was obtained by immersing it in the added developer (25°C) for 2 minutes and rinsing with water. As a result, no matter which developer was used, the sensitivity at 365 nm was jlOmJ/l.
i, and the γ value was 3.

Furthermore, with either developer, a pattern of 10 μm could be resolved by contact exposure. Subsequently, the underlying PIQ was subjected to oxygen plasma etching under the same conditions as in Example 6, and a fine PIQ pattern with an aspect ratio of 201 μm and a line width could be formed.

〔Effect of the invention〕

As described above, the photosensitive composition of the present invention uses an alkaline development method similar to the current mainstream resists, alkaline stage type resists, and also has photosensitive properties equivalent to or better than those. Therefore, the current syrocess can be used without changing.Furthermore, the photosensitive composition of the present invention
Since it has superior oxygen plasma resistance compared to conventional resists, it can be used as an upper layer resist in a two-layer resist method.

As described above, the photosensitive composition of the present invention is extremely effective.

[

Claims (1)

[Claims] 1. The following general formula (1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(1) (However, in general formula (1), R_1, R_2, and R_
3 represents a monovalent organic group, R_4 represents an alkyl group, and OH
The number l of groups and OR_4 groups is 1 or 2, m and n are integers at arbitrary positions on the benzene ring, m+n is 2 to 200, and n/(m+n) is 0.4 or more. ); 70 to 95% by weight of a polymer containing at least 70% by weight of an alkali-soluble silmethylene polymer; and 30 to 5% by weight of a photosensitizer that is alkali-insoluble before light irradiation and becomes alkali-soluble upon light irradiation; A photosensitive composition comprising: 2. In claim 1, the photosensitizer has the following general formula (2) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼... (2) (However, in general formula (2), R_3 is a monovalent 1. A photosensitive composition comprising a compound represented by the following organic group (-SO_2-R_3 is the 4th or 5th position of 1,2-naphthoquinonediazide). 3. In claim 1, R_1, R_2 and R_4 in general formula (1) are methyl groups, R_3 is hydrogen, l is 1, and OH group and OR_4 group are P- on the benzene ring. A photosensitive composition characterized in that: 4. In claim 2, R_5 in general formula (2) is ▲a mathematical formula, a chemical formula, a table, etc.▼, ▲a mathematical formula, a chemical formula,
There are tables, etc. ▼ ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ A photosensitive composition characterized in that the position of -SO_2-R_5 is the 5th position.