JPH01101311A - Silicon atom-containing ethylenic polymer, composition containing said polymer and method for use thereof - Google Patents

Abstract

PURPOSE:To obtain an Si-containing ethylenic polymer, having the backbone chain constituted of specific structural units and a specified mol.wt. and capable of forming fine patterns with extremely high sensitivity even to near ultraviolet rays and exhibiting higher resistance to dry etching. CONSTITUTION:An Si atom-containing ethylenic polymer having the backbone chain constituted of structural units expressed by the formula and 3,000-1,000,000mol.wt. The above-mentioned ethylenic polymer is used as a resist composition by adding a bisazide [e.g. 4,4'-diazidochalcone or 2,6-di-(4'- azidobenzal)cyclohexanone] as a photocrosslinking agent in amount of normally 0.1-30wt.% based on the polymer. Alternatively, an organic film and a resist layer having a resist pattern are successively formed on a substrate and the above-mentioned resist layer is formed from the afore-mentioned ethylenic polymer by a method for forming the pattern according to a two-layer structural resist method using the above-mentioned resist pattern as a dry etching mask for the organic film.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a silicon atom-containing ethylene polymer, a resist composition containing this polymer, and a method for using the same.
In particular, the present invention relates to a silicon atom-containing ethylene polymer, a resist composition, and a pattern forming method suitable for forming fine patterns in semiconductor integrated circuits, magnetic bubble printing, and the like.

[Prior Art] When forming fine patterns using optical lithography or electron beam lithography in the manufacture of integrated circuits, bubble memory devices, etc., in optical lithography, the influence of reflected waves from the substrate, and in electron beam lithography, It has been shown that the resolution decreases when the resist is thick due to the influence of electron scattering. J for development
Dry etching is used to transfer a resist pattern onto a substrate with good viscosity, but when a thin resist layer is used to obtain a high-resolution resist pattern, the dry etching process also removes the resist. It has the disadvantage that it does not have sufficient resistance to etching and processing substrates. Further, in the step portion, it is necessary to apply a thick layer of resist 1 to flatten the step, and it can be said that it is extremely difficult to form a fine pattern on such a resist layer.

In order to solve these inconveniences, SanM@-made resists were developed by J.M. Horan et al.
and rechno+ogy), Volume 16, 162
It is proposed on page 0 (1979). In a three-layer structure, a thick organic layer is applied as the third layer (bottom layer), and then an inorganic layer, such as a silicon oxide film, silicon nitride film, or silicon film, which is difficult to be etched by dry etching using 02, is used as an intermediate layer. form a substance material;

Thereafter, a resist is spin-coated onto the intermediate layer, and the resist is exposed and developed using an electron beam or light.

Using the obtained resist pattern as a mask, the intermediate layer is dry-etched, and then, using this intermediate layer as a mask, a thick organic layer is etched by a reactive sputter etching method using 02. This method allows converting a high-resolution resist pattern into a thick organic layer pattern. However, in this method, after forming the first layer, the intermediate layer is formed by vapor deposition, sputtering, or plasma CVD, and the patterning resist is roughly applied, making the process complicated and long. There are drawbacks.

If the patterning resist is resistant to dry etching, a thick organic layer can be etched using the patterning resist as a mask, resulting in a two-layer structure and simplifying the process.

[Problems to be Solved by the Invention] It is known that polydimethylsiloxane has extremely high resistance to oxygen reactive ion etching (02RIE) and has an etching rate of almost zero (G.N.
Taylor, T. M. Wolff and G. M. Moran, Journal of Vacuum Science and Technology, 19(4), 872.1.
981 (G.N.Taylor.

T, H, W'olf and J, H, Horan,
J,VaCuUm Sci,andTech,, 19
(4), 872.1981)) However, since this polymer is liquid at room temperature, it is not suitable as a resist material because it tends to attract flakes and it is difficult to obtain high resolution.

We have already proposed trialkylsilylstyrene homopolymers and copolymers as the above-mentioned patterning resists [Japanese Patent Application No. 123866/1983
-15419), Japanese Patent Application No. 57i23B65 (Japanese Unexamined Patent Publication No. 59-15243)]. However, these polymers have excellent sensitivity to deep ultraviolet or electron beam exposure, so they are suitable for far ultraviolet or electron beam exposure regime 1.
However, it did not crosslink when exposed to near-ultraviolet and visible light, and could not be used as a photoresist.

In addition, we have already filed a patent application in 1986 to provide a silane polymer as a resist for optical exposure for the above-mentioned patterning.
-001636, Japanese Patent Application No. 60-001637).

However, the resist provided here has a silicon atom concentration of about 10 to 13% (-/old) relative to the polymer, so if the lower layer is thick, for example, if the thickness of the lower layer is 1.5 or more, it can be used as the upper layer for patterning. Etching resistance was insufficient.

The object of the present invention is to be able to form fine patterns with extremely high sensitivity to electron beams, X-rays, deep ultraviolet rays, ion beams, or near ultraviolet rays in addition to these, and to have greater resistance to dry etching. An object of the present invention is to provide a polymer, a composition containing the same, and a method for using the same.

゛[Means for solving the problem] As a result of continuing research in view of the above situation, the present inventors have discovered a polymer having two silicon atoms and an allyl group in the monomer unit of the polymer. Then, it is extremely resistant to the reaction caused by the rI wire. We discovered that it has extremely high sensitivity, and that when a bisazide compound is added, it becomes extremely sensitive to near ultraviolet rays.
The present invention has been accomplished.

1. The present invention is characterized in that the main chain is composed of the following IU small units, and the silicon atom-containing ethylene polymer has a molecule M of 3,000 to 1,000,000. A resist composition made of bisazide, and a resist layer having an organic film and a predetermined resist pattern are sequentially formed on the substrate,
In a pattern forming method using a two-layer resist method in which this resist pattern is used as a dry etching mask for 811R, the resist layer is formed of the silicon atom-containing ethylene polymer or a composition of this polymer and bisazide. This is a pattern forming method characterized by the following.

Generally, when a polymer is used as a negative resist, high sensitivity is obtained if the polymer matrix is used, but resolution is impaired due to swelling during development. Generally, if the molecular weight exceeds 1,000,000, high resolution cannot be expected. On the other hand, reducing the molecular weight improves resolution, but not only does the sensitivity drop in proportion to the molecular weight, making it impractical, but it also becomes difficult to form uniform and solid shadows below the molecular weight. There's a problem. Therefore, the molecular weight of the silicon atom-containing ethylene polymer is 3000-1
A value in the range of 000000 is suitable.

The silicon atom-containing ethylene polymer of the present invention can be produced, for example, as follows.

(Space below) n-butyllithium in hexane at 20°C (in the formula, X represents a positive integer) As shown in the above formula, the polymer of the present invention uses n-butyllithium (n-BuLi). Polymers with low polydispersity and arbitrary molecular weights ranging from low to high molecular weights can be produced by anionic polymerization methods.

This polymer is soluble in common organic solvents such as hexane, benzene, chloroform, and methyl ethyl ketone, but insoluble in methanol and ethanol.

The resist material in the present invention is extremely sensitive to electron beams, X-rays, and deep ultraviolet rays as it is, but when bisazide, which is known as a photocrosslinking agent, is added, the resist becomes highly sensitive to ultraviolet rays. The bisazides used in the present invention include 4.4°-diazide chalcone, 2,6
-Z(4°-azidobenzal)cyclohexanone, 2
．． 6-di(4°-azidobenzal)-4-methylcyclohexanone, 2.6-di(4-azidobenzal)-
Examples include 4-hydroxycyclohexanone. If the amount of photocrosslinking agent added is too little or too much, the sensitivity to ultraviolet rays will decrease, and if the amount of photocrosslinking agent added is too much, the composition will be 0.
Since it impairs the resistance to dry etching of No. 2, it is desirable to add 0.1 to 30% by weight based on the polymer.

It is known that the uniformity of molecular weight distribution also affects resolution, and the smaller the polydispersity, the better the resolution. In this respect, the above-mentioned method of manufacturing from an anionic polymerization method directly produces small polydispersities, such as 1.
Since a polymer of 2 or less is obtained, the resist material has excellent resolution.

[Example] Next, the present invention will be explained by examples.

The 500d flask was completely purged with dry nitrogen gas. 4.8 g (0.2 gram atom) of magnesium and 10 ml of ether were charged and a small amount of ethyl bromide was added to activate the magnesium. Ether 200rIdl
After that, 24.2 g (0.2 mol) of allyl bromide was added dropwise under mild reflux. After the dropwise addition was completed, the reaction was further continued at room temperature for 2 hours. In another 500rd flask, 43.8q (0.2 mol) of 1,3-dichlorotetramethyldisilylthioether and 100d of ether were charged, and the Grignard reagent prepared above was added dropwise at room temperature to cool down the generation of heat. It became a state of reflux. After the dropwise addition was completed, the reaction was continued at room temperature for approximately 4 hours. After the reaction was completed, it was filtered, and the solvent of the filtrate was distilled off under reduced pressure. The residue was distilled to obtain the target compound. 23.3q (
The yield was 52%).

Magnesium 4.8Cl (0,2
grams atom) and tetrahydrofuran (THE) 30
A small amount of ethyl bromide was added and heated.

After returning to room temperature, 21.4 g (0.2 mol) of vinyl bromide
A solution of 50 rnl of T HF was added over a period of 1 hour.

The reaction was continued for 4 hours under rough reflux, and then cooled to room temperature. In another 300rrJi flask, 33.7 (II (0.15 mol)) of 1-allyl-3-chlorotetramethyldisilylthioether prepared in Raw Material Production Example 1 and T
I prepared HF50d. The mixture was brought to reflux and the Grignard reagent prepared above was added dropwise over a period of 1 hour. Roughly, the reaction was continued under a far current state for 1 hour, and then cooled to room temperature. The reaction solution was poured into a dilute 11CJl solution, and 500 d of ether was added to perform extraction. After drying the ether layer with magnesium sulfate, the ether was distilled off, and the residue was distilled to obtain the target compound 13C7 (40%).

Example 1 The monomer synthesized in Raw Material Production Example 2 and THF were pre-dried with calcium hydride. All polymerization reactions described below were performed under high vacuum.

The monomer tig produced in Raw Material Production Example 2 was charged into a flask with 10 (7) branches, the branches were sealed with a rubber septum, and the flask was connected to a high vacuum line. After freezing in a liquid nitrogen bath, the mixture was reduced to a vacuum. After repeating this operation four times to degas the air contained in the monomer, n-butyllithium (1,6, M:>0.5d in hexane was added to The body was completely dehydrated.Then, it was distilled into a similar side flask. 50rdl of THF was similarly degassed and dehydrated, and then distilled into a polymerization flask.N-Butyllithium was extracted from a rubber septum at room temperature using a microsyringe. (
1,6M in hexane) was added and immediately cooled in an acetone-dry ice bath to carry out polymerization. After 2 hours, 1 ml of methanol was added using a syringe to stop polymerization, the pressure was returned to normal pressure, and the polymer solution was poured into 500 ml of methanol. The polymer precipitated as a white solid and was separated by filtration.

Roughly dissolve in 100 d of benzene and add 50 d of methanol (
7! I invested in it. After repeating this operation three times, it was dried at 50°C under reduced pressure. The yield of the target compound was 10.2 g (93% yield).

Weight average molecular weight (MW) = 56,000 Number average molecular weight (Mn) = 53,000 Polydispersity (Mw/Mn)
= 1.0 has two silicon atoms in one unit, so the silicon-containing matrix is 25.9% of the total polymer.
% (W/W).

Example 2 After dissolving 0.42 g of the polymer produced in Example 1 and 0.021 CI of 2,6-di(4°-azidobenzal)-4-methylcyclohequilinone in 6.0 m of xylene and stirring thoroughly, , filtered through a 0.2-μm filter to obtain a sample solution.This solution was spin-coated onto a silicon substrate (30-μm).
00 rpm) L, 80'C, 30 minutes.

Ultraviolet exposure equipment () IANN 48000S (GCA
Exposure was performed using a chrome mask (manufactured by Co., Ltd.) through a chrome mask.

After developing by immersing it in methyl isobutyl ketone (RI8K) for 1 minute, it was rinsed with isopropanol for 1 minute. After drying, the film thickness of the irradiated area was measured using a stylus method. The initial film thickness was 0.25 mm. Whether or not fine patterns were resolved was determined by drawing line-and-space patterns of various dimensions and observing the resist images obtained by development using an optical microscope or a scanning electron microscope.

From the sensitivity curve, it was found that the gel point CD9') was approximately 0.96 seconds. Shipley MP-1300 (1j) is a photoresist widely used in ultraviolet exposure.
I! The appropriate exposure amount for the film (n thickness) was 0.38 seconds.

Example 3 A resist material (HP-1300 (manufactured by Shipley)) containing novolak resin as a main component was deposited on a silicon substrate to a thickness of 1.
5IIIn was applied and baked at 250° C. for 1 hour. After that, the solution prepared in Example 2 was applied by spin coating and dried at 80'C for 30 minutes to give a coating of 0.251I.
! A uniform coating film with a thickness of r1 was obtained. This substrate was exposed to light for 10.0 seconds through a chrome mask using an ultraviolet exposure device (4800DSW (manufactured by GCA)). )lIBK/n-B
After developing by immersing it in uOH (50/100V/V) for 1 minute, it was rinsed with isopropanol for 1 minute. This substrate was etched using a parallel plate reactive sputter etching device (DEN-451, manufactured by Anelva Corporation).
cm.

Etching was performed for 25 minutes under the conditions of 3. OPa and 0.16 W/cm2. As a result of observation with a scanning electron microscope,
It was found that the submicron upper layer pattern was accurately transferred by the lower layer resist material, forming a more vertical pattern.

[Effects of the Invention] As explained above, since the polymer of the present invention has two silicon atoms per structural unit, it has a high silicon concentration, that is, 25.9% (W/W).

Therefore, the resist composition is extremely resistant to dry etching, and if it has a zero film thickness of about 2000, it can be used as a mask for etching an organic layer as thick as about 1.5 dust. Therefore, the resist film for pattern formation may be thin. Furthermore, a thick organic layer on the base reduces the proximity effect in electron beam exposure, and reduces the adverse effects of reflected waves in optical exposure, making it easy to obtain a high-resolution pattern. Also, high-resolution patterns can be easily obtained using other exposure methods.

Furthermore, when the polymer of the present invention is synthesized by an anionic polymerization method, a polymer with a small polydispersity of molecular weight distribution can be obtained,
Therefore, when the composition of the above-mentioned polymer and bisazide is used as a resist, the resulting pattern has better resolution.

Claims (4)

[Claims] (1) A silicon atom-containing ethylene polymer having a molecular weight of 3,000 to 1,000,000, whose main chain is composed of the following structural units. ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ (2) Molecular weight 300 with main chain composed of the following structural units
A resist composition characterized by comprising an ethylene polymer containing 0 to 1,000,000 silicon atoms, and ▲numerical formula, chemical formula, table, etc.▼ bisazide. (3) A pattern forming method using a two-layer resist method in which an organic film and a resist layer having a predetermined resist pattern are sequentially formed on a substrate, and this resist pattern is used as a dry etching mask for the organic film,
A pattern forming method characterized in that the resist layer is formed of a silicon atom-containing ethylene polymer having a molecular weight of 3,000 to 1,000,000 and whose main chain is composed of the following structural units. ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ (4) A pattern forming method using a two-layer resist method, in which an organic film and a resist layer having a predetermined resist pattern are sequentially formed on a substrate, and this resist pattern is used as a dry etching mask for the organic film,
The resist layer is formed of a composition consisting of a silicon atom-containing ethylene polymer with a molecular weight of 3,000 to 1,000,000 whose main chain is composed of the following structural units, and a bisazide. A pattern forming method characterized by: