JPH07152156A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin compsn. capable of preventing postpolymn. ind having sensitivity comparable to that of a conventional resin compsn. CONSTITUTION:This resin compsn. is prepd. by dissolving 190g (1mol) poly(di-t- butoxysiloxane) represented by the formula and having a wt. average mol. wt. of 10,000 and a terminal OH group, 10.1g (0.02mol) hexa(t-butoxy)siloxane as a crosslinking agent and 8.25g (0.02mol) triphenylsulfonium triphthalate (Ph3S<+> OTf<->) as an acid generating agent in 1,780g monochlorobenzene.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition suitable as a constituent material of a resist used for manufacturing a semiconductor device or the like, particularly for manufacturing an active element or a wiring pattern.

[0002]

2. Description of the Related Art In order to achieve high integration and high speed of a semiconductor integrated circuit (IC), miniaturization and multi-layering of wiring are being advanced in the manufacture of IC. However, the aspect ratio of the wiring tends to be high in order to prevent the increase of wiring resistance due to miniaturization, and the step difference on the substrate to be processed becomes larger as the wiring becomes multi-layered. . Therefore, when a resist pattern is formed on a substrate having such a step by using, for example, a reduction projection exposure apparatus, the step becomes beyond the range of the depth of focus of the exposure apparatus. A patterning method using one layer of resist may not be able to form a desired pattern. In particular, in the submicron region, a reduction projection exposure apparatus equipped with a lens having a large numerical aperture tends to be used, and the depth of focus becomes shallower.

Therefore, as one of the techniques for solving this, for example, a document I (PolymerEngineeri) is used.
ng and Science (Polymer Engineering and Science), Vol. 23, 1983,
p. p. 1054 to 1058) disclosed the technology.
It was related to a resist pattern forming technique called a two-layer resist process and a negative resist having sensitivity to an electron beam used for the technique.

In the technique disclosed in Document I, for example, when a wiring pattern is formed from a metal layer formed on a substrate having a step, the following procedure is taken.

First, a thermosetting resin is applied thickly (1.5 to 3 μm thick) on a metal layer on a substrate to be processed. Next, this is heat-cured to form a lower layer. The lower layer flattens the step of the substrate to be processed. Next, on this lower layer, the electron beam sensitive resin composition having high resistance to etching by oxygen plasma is extremely thin (0.2 to 0.3 μm).
m thickness) is applied. Next, this resin composition is exposed and developed to obtain an upper resist pattern. Next, with the upper layer resist pattern as a mask, the lower thermosetting resin layer is selectively etched by ion etching (O ₂ -RIE) using reactive oxygen gas. As a result, a bilayer resist pattern having a high aspect ratio can be obtained. Then, using this as a mask, the underlying metal layer on the substrate to be processed is etched to form a desired wiring pattern.

The advantage of the two-layer resist process is that the pattern of the photosensitive resin layer is formed on the thick flattening layer (lower layer), so that it is affected by the step on the substrate when patterning the photosensitive resin layer. Therefore, a high aspect ratio fine pattern can be formed without dimensional variation.

Examples of the electron beam sensitive resin composition for the upper layer used in the two-layer resist process include those using a poly (siloxane) derivative. For example, in the above Document I, the electron beam sensitive resin composition is composed of poly (methyl-vinylsilsesquioxane) itself.
This was because the portion irradiated with the electron beam was crosslinked and the portion became insoluble in the developing solution, and had a sensitivity of ² μC / cm ² and a resolving power of 0.5 μm.

[0008]

However, poly (methyl-vinylsilsesquioxane) has a vinyl group which is a chain-reactive substituent. Therefore, when this resin composition is exposed by an electron beam drawing apparatus, the electron beam drawing generally takes a long time, so that radicals generated by the electron beam cause post-polymerization, and as a result, first There is a problem that a dimensional difference may occur between the exposed pattern and the finally exposed pattern. In the case of the above poly (methyl-vinylsilsesquioxane), as a method for preventing the post-polymerization, a measure such as increasing the proportion of vinyl groups can be considered. However, the sensitivity of the resist is lowered when the resist is made of the resin composition provided with such measures as compared with the case where the resist is not formed.

The present invention has been made in view of the above circumstances, and therefore an object of the present invention is to provide a resin composition capable of preventing post-polymerization and exhibiting at least the same sensitivity as conventional ones. is there.

[0010]

In order to achieve this object, the resin composition of the present invention has a poly (siloxane) derivative represented by the following formula (1) and a formula (2) below. Any one of these poly (siloxane) derivatives or a copolymer thereof, a cross-linking agent, and an acid generator that generates an acid upon exposure to light (provided that R ¹ and R ^{2 in the} formula are used. , R ³ and R ⁴ represent an alkyl group and may be the same or different, and m and n represent a positive integer.).

[0011]

[Chemical 1]

According to this structure, a novel resin composition in which a chemical amplification type resist composed of a resin and an acid generator is further added with an element of a crosslinking agent is constituted. Since it is a chemically amplified type, post-polymerization is prevented. In addition, since a crosslinking agent is included, a highly sensitive resist that cannot be achieved with a two-component system of a resin and an acid generator is realized. That is, this resin composition is treated with an appropriate radiation source (eg, electron beam, X
When exposed to light (line, light) and further heated, the alkyl group of the poly (siloxane) derivative is desorbed from the Si chain by acid and heating, and the silanol generated thereby is condensed, so that it can be used as a negative resist.

Here, the end of such a poly (siloxane derivative) is not particularly limited (except for a chain-reactive group, of course), and may be, for example, an OH group, a trimethylylsilyl group or an alkoxy group.

In carrying out the present invention, a polysiloxane derivative having a weight average molecular weight of 500 to 10,000 is used.
It is preferably in the range of 0. If the weight average molecular weight is less than 500, it takes a long time to form the film (SiO ₂ ) and is not practical, and the weight average molecular weight is 1000.
This is because it is difficult to perform the synthesis with a controllability of the molecular weight when the value is larger than 00.

A part of such a poly (siloxane) derivative is part of Japanese Patent Application No. 4-1758 filed by the applicant of the present application.
It is the compound described in JP-A-8. In addition, regarding a method for synthesizing a part of such poly (siloxane) derivative, Japanese Patent Application No. 4-02088 filed by the applicant of the present application also discloses.
No. 9 publication.

Further, in carrying out the present invention, it is preferable that the crosslinking agent is represented by the following formula (3).

(R ⁵ O) _q R ⁶ _r Si _p O _(p-1) (3) where p, q, and r are 1 ≦ p, 2 ≦ q ≦ 2 (p +
1), a positive integer that satisfies r = 2 (p + 1) -q.
Further, q R ^{5 s} each represent hydrogen, an alkyl group, an aryl group or an alkenyl group, and may be the same or different. Further, each of r R ^{6 s} represents a monovalent hydrocarbon group or hydrogen, and may be the same or different. When a substance represented by the formula (3) and R ⁵ in the formula is hydrogen is used as the crosslinking agent, the silanol of the crosslinking agent is condensed in the same manner as the condensation of the silanol of the poly (siloxane) derivative. To do. When the substance represented by the formula (3) and R ⁵ in the formula is an alkyl group, an aryl group or an alkenyl group, these groups are eliminated by acid and heating, and the silanol produced thereby is condensed. To do. Further, since the cross-linking agent represented by the formula (3) itself contains a large amount of silicon, it is possible to increase the Si content in the resin composition as compared with the case where a cross-linking agent not containing Si is used, and therefore, the oxygen plasma resistance It also has the advantage that it can be improved. Further, the content of the cross-linking agent (not limited to that of the formula (3)) is preferably in the range of 0.05 to 50% with respect to the weight of the poly (siloxane) derivative or copolymer. .
If the content is less than this, the effect as a cross-linking agent cannot be obtained, so that it is not possible to achieve high sensitivity, and furthermore, it is necessary to carry out the heat treatment for causing the resin and the acid generator to act after exposure at a high temperature. Occurs. On the other hand, if the content is higher than this range, the coating film may become brittle. The crosslinking agent is more preferably contained in an amount of 0.05 to 30%.

In carrying out the present invention, the acid generator is not particularly limited as long as it is a substance that generates an acid upon exposure, and is selected from the substances shown in (4) to (8) below. Can be done.

[0019]

[Chemical 2]

[0020]

[Chemical 3]

Specifically, (4) and (5) are onium salts,
(6) is p-toluene sulfonate, (7) is trichloromethyl-substituted triazine, and (8) is trichloromethyl-substituted benzene. Among the onium salts, (4) is a sulfonium salt and (5) is an iodonium salt. These onium salts are commercially available or are described in J. V. Crivel
Lo et al., for example, the document “J. Polymer”.
Sci. , Polymer Chem. Ed. 18, 2
677 (1980) ”, T. The method by Endo et al.
For example, the document “J. Polymer Sci., Poly”
mer Chem. Ed. 23, 359 (1985). It is possible to easily deal with various exposure sources by selecting what is used as the acid generator. The content of the acid generator is preferably in the range of 0.01 to 50% based on the weight of the poly (siloxane) derivative or copolymer. If the content is less than this, it is necessary to carry out a heat treatment for causing the resin and the acid generator to act after exposure at a high temperature, and if the content is more than this, the coating film may be fragile. Because. The acid generator is more preferably contained in an amount of 0.1 to 30%. Also, when determining the type and content of the acid generator,
The heat treatment for causing the resin and the acid generator to act after exposure is performed at 40 to 300 ° C., preferably 60 to 200 ° C.
It is preferable to consider so that the temperature can be set to ° C. This is because the system of an acid generator that reacts at a temperature lower than 40 ° C. has a problem in storage stability of the resin composition (resist). Also,
This is because a system of an acid generator that does not react unless it is at a high temperature has a risk of exerting a bad influence on a base (substrate or the like).

In using the resin composition of the present invention, a coating solution of the resin composition is prepared.
Examples of the solvent used in that case include monochlorobenzene, methyl isobutyl ketone, diglyme, and cyclohexanone.

[0023]

EXAMPLES Examples of the resin composition of the present invention will be described below. The materials used and their amounts, processing time, temperature and other numerical conditions described in the following description are merely examples within the scope of the present invention. Therefore, the present invention is not limited to these conditions.

1. First Example As one kind of the poly (siloxane) derivative represented by the above formula (1), the weight average molecular weight is represented by the following formula (9) and is 1
190 g (1 mol) of poly (di-t-butoxysiloxane) of which the number is 0000 and has an OH group at the end, and the following formula (10) which is one of the compounds of the above formula (3) as a crosslinking agent Hexa (t-butoxy) siloxane 10.1 g (0.02 mol) and an acid generator,
Triphenylsulfonium triflate (Ph ₃ S ⁺ OTf ⁻ ) represented by the following formula (11) ^: 8.25 g (0.0
2 mol) is dissolved in 1780 g of monochlorobenzene and filtered through a membrane filter having pores with a pore diameter of 0.2 μm to prepare the coating liquid of Example 1.

[0025]

[Chemical 4]

The hexa (t-butoxy) siloxane used as the crosslinking agent is synthesized by the following method.
283 g of tri (t-butoxy) chlorosilane (1 mo
1) and 5 l (liter) of methyl isobutyl ketone are cooled to -40 ° C with a dry ice and acetonitrile bath. 138.5 ml of triethylamine and 18 g of water (1 m
ol) is added dropwise and the mixture is stirred for 3 hours in that state. The obtained organic layer is washed with water, dried over magnesium sulfate, and the solvent is distilled off to obtain hexa (t-butoxy) siloxane.

On the other hand, a photoresist (here, MP2400 manufactured by Shipley Co., Ltd.) was coated on a silicon substrate by a spin coating method, and this was heat-cured in an oven at a temperature of 200 ° C. for about 1 hour to give a film thickness of 1. A 5 μm lower resist layer is formed.

Next, the coating solution of the first embodiment prepared above is applied onto the lower resist layer by a spin coating method to form a film having a thickness of 0.2.
Apply so that it becomes μm, and apply it at 80 ℃ with a hot pot.
The pre-exposure bake is performed at the temperature of 1 minute. Next, line and space (L / S) patterns having various dimensions are drawn on the exposed resist layer by an electron beam drawing method. Then, this sample is 1
Baking was performed at a temperature of 00 ° C. for 2 minutes, followed by immersion in anisole for 20 seconds and then in xylene for 20 seconds to obtain an upper resist pattern. It was found that the sensitivity (D _n ^0.5 ) was 1.5 μC / cm ² , which was higher than that of the comparative example described later, and that the L / S pattern of 0.3 μm could be resolved. In electron beam writing, even when the upper layer resist is irradiated with an electron beam for 4 hours, there is a difference in the line width between the pattern drawn immediately after the start of drawing and the pattern drawn just before the elapse of 4 hours. It turned out that it did not occur. From this, it can be understood that post-polymerization does not occur in electron beam drawing.

As a comparative example, a resin composition having a constitution in which the crosslinking agent is removed from the constitution of the resin composition of the first embodiment is prepared.
Then, using this coating solution, a patterning experiment is conducted in the same manner as in the above embodiment. The sensitivity of the resin composition of Comparative Example (D _n
^0.5 ) was found to be 2.0 μC / cm ² .
Also in the case of the resin composition of Comparative Example, there was no difference in the line width between the pattern drawn immediately after the start of drawing and the pattern drawn immediately before the lapse of 4 hours.

Further, the sample in which the upper layer resist pattern is formed in the first embodiment is etched by the O ₂ -RIE method using a parallel plate type dry etcher (manufactured by Nichiden Anelva) called DEM451. In this etching, the portion not covered with the upper resist layer of the lower resist layer is selectively etched to 0.3 μm.
A bilayer resist pattern having L / S and an aspect ratio of 5 was obtained. The etching conditions at this time are O
₂ gas pressure 1.0 Pa, O ₂ gas flow rate 20 SCCM, RF
The condition is a power density of 0.12 W / cm ² .

In the patterning step of the resin composition of the first embodiment, the exposure light source is Xe-H instead of the electron beam.
A patterning experiment is performed in the same procedure as in the above-described embodiment except that the g lamp (CM250 cold mirror mounted) is used. However, exposure is performed through a photomask having L / S patterns of various sizes. It was found that the (D _n ^0.5 ) of the resin composition of the first example when using the Xe = Hg lamp was 9 mJ / cm ² . In addition, the minimum line width of the photomask used is 0.5μ.
It was found that the mL / S pattern could be resolved.

2. Second Example Instead of the poly (siloxane) derivative used in the first example, the terminal of the derivative is trimethylsilylated, and the weight average molecular weight is 1100 as shown by the following formula (12).
A poly (siloxane) derivative of 0 is used. Except for this, the resin composition of the second embodiment is prepared in the same manner as in the first embodiment, and the patterning experiment by electron beam is performed.
The (D _n ^0.5 ) of the resin composition of the second embodiment is 18 μC.
It was found to be / cm ² . Also, L of 0.3 μm
It was found that the / S pattern can be resolved. Further, also in the case of the resin composition of the second example, even when the electron beam exposure was performed for 4 hours, the pattern drawn immediately after the start of drawing and the pattern drawn immediately before the lapse of 4 hours, It was found that there was no difference in line width. The sensitivity of the resin composition of the second embodiment was lower than that of the resin composition of the first embodiment because the polymer terminal was trimethylsilylated.

[0033]

[Chemical 5]

3. Third Example Instead of the poly (siloxane) derivative used in the first example, the weight average molecular weight represented by the following formula (13) is 1
5,000 poly (di-t-butoxylsesquioxane) is used. Other configurations are the same as in the first embodiment, the resin composition of the third embodiment is prepared, and the patterning experiment by electron beam is conducted. It was found that the resin composition of the third example had a (D _n ^0.5 ) of 3 μC / cm ² . It was also found that the L / S pattern of 0.3 μm can be resolved. Also in the case of the resin composition of the third example, even when the electron beam exposure was performed for 4 hours, the pattern drawn immediately after the start of drawing and the pattern drawn just before the elapse of 4 hours, It was found that there was no difference in line width.

[0035]

[Chemical 6]

4. Fourth Example Instead of hexa (t-butoxy) siloxane used as the cross-linking agent in the first example, tetraphenoxysilane [(PhO) ₄ Si] is used as the cross-linking agent. The rest of the construction is the same as in the first embodiment, the resin composition of the fourth embodiment is prepared, and the patterning experiment by electron beam is conducted. The (D _n ^0.5 ) of the resin composition of the fourth example is 7.
It was found to be ² μC / cm ² . In addition, 0.3μ
It was found that the m / L pattern can be resolved. Also in the case of the resin composition of the third example, even when the electron beam exposure was performed for 4 hours, the pattern drawn immediately after the start of drawing and the pattern drawn just before the elapse of 4 hours, It was found that there was no difference in line width.

Although the embodiments of the resin composition of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments.

For example, in the above-mentioned examples, the resin composition was constituted by giving an example of each of the poly (siloxane) derivative represented by the formula (1) and the poly (siloxane) derivative represented by the formula (2). Even when a copolymer of a po (siloxane) derivative represented by the formula) and a poly (siloxane) derivative represented by (2) is used, the same effect as that of the embodiment can be expected. Further, it is apparent that suitable crosslinking agents and acid generators other than those in the examples are used.

Further, in the above-mentioned embodiment, an example in which the resin composition of the present invention is used for the upper layer resist of the two-layer resist process is shown. However, it is clear that the resin composition of the present invention can be used alone.

[0040]

As is apparent from the above description, according to the resin composition of the present invention, a novel chemical composition of a chemically amplified resist composed of a resin and an acid generator to which a cross-linking agent is added is added. A resin composition of various types is constituted. Post-polymerization can be prevented by using the chemically amplified type, and since a crosslinking agent is included, a highly sensitive resist that cannot be achieved by a two-component system of a resin and an acid generator is realized.

Because of this, it is possible to provide a resin composition which can prevent post-polymerization and which is more sensitive than in the past.

Claims (4)

[Claims] 1. A poly (siloxane) derivative represented by the following formula (1) and a poly (siloxane) derivative represented by the following formula (2) or a copolymer thereof, a cross-linking agent, and exposure. A resin composition (provided that R ¹ , R ² ,
R ³ and R ⁴ represent an alkyl group and may be the same or different. Moreover, m and n show a positive integer. ). [Chemical 1] 2. The resin composition according to claim 1, wherein the cross-linking agent is represented by the following formula (3) (wherein p, q, and r are: 1
It is a positive integer that satisfies ≦ p, 2 ≦ q ≦ 2 (p + 1), and r = 2 (p + 1) -q. In addition, q R ^{5 s} in the formula each represent hydrogen, an alkyl group, an aryl group or an alkenyl group, and may be the same or different. Further, each of r R ^{6 s} in the formula represents a monovalent hydrocarbon group or hydrogen, and may be the same or different. ). (R ⁵ O) _q R ⁶ _r Si _p O _(p-1) (3) 3. The resin composition according to claim 1, wherein the crosslinking agent is contained in an amount in the range of 0.05 to 50% based on the weight of the poly (siloxane) derivative or copolymer. A characteristic resin composition. 4. The resin composition according to claim 1, wherein the acid generator is contained in an amount in the range of 0.01 to 50% based on the weight of the poly (siloxane) derivative or copolymer. And a resin composition.