JPH02251961A - Fine pattern forming material and pattern forming method - Google Patents

Abstract

PURPOSE:To easily form exact and fine patterns which obviate the generation of a charge-up by consisting the above material of the polymer of a specific polydiacetylene system. CONSTITUTION:The conductive high-polymer material of the polydiacetylene system expressed by formula I (in the formula I, R1 to R4 denote an alkyl group, alkoxy group which are the same or different; n denotes a positive integer) is used as an electron ray resist. This high-polymer material has conjugated double bonds in the main chain and exhibits a high electrical conductivity and, therefore, the charge-up by electrons can be prevented. Since the triple bonds cause a polymn. reaction by being easily decomposed by an electron beam, the negative type resist which exhibits the high sensitivity to the electron beam is obtainable. The negative type resist patterns having the high sensitivity and high resolution are formed in this way and the charge-up is easily prevented. The exact and fine resist patterns which are perpendicular are thus formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a fine pattern forming material used in patterning and fabricating semiconductor elements and integrated circuits using electron beams, and a fine pattern forming material using the same material. This relates to a forming method.

2. Description of the Related Art Conventionally, in the manufacture of ICs, LSIs, etc., patterns have been formed by photolithography using ultraviolet rays. With the miniaturization of elements, higher HA stepper lenses and the use of short wavelength light sources are being promoted.
This has the disadvantage that the depth of focus becomes shallow. In addition, electron beam lithography has come to be used as the pattern dimensions of LSI devices become finer and munici (Music ICs) are manufactured. A positive electron beam resist is indispensable for forming fine patterns by electron beam lithography. Among them, polymethyl methacrylate (PMM) is known to have the best resolution, but its drawback is low sensitivity. Therefore, in recent years, many reports have been made to improve the sensitivity of positive electron beam resists, such as polybutyl methacrylate.

A copolymer of methacrylic acid methyμ and methacrylic acid.

Copolymer of methacrylic acid and acrylonitrile.

Copolymer of methyl methacrylate and inbutylene.

Positive electron beam resists such as phoripten-1-sulfone, polyisopropenyl ketone, and fluorine-containing polymethacrylate have been announced. All of these resists are resists in which the main chain is easily cleaved by an electron beam by introducing an electron-withdrawing group into the side chain or a degradable bond into the main chain. Although it aims to increase sensitivity, it has problems such as poor dry etch resistance and charge-up effects due to insulation.

In addition, electron beam lithography has drawbacks such as deterioration of pattern accuracy due to the proximity effect due to forward scattering and backward scattering of electrons. A multilayer resist process is an effective method. FIG. 4 is a diagram illustrating a multilayer resist process in electron beam lithography. Lower layer film 41 to suppress the proximity effect
A polymeric organic film is coated with a thickness of 2 to 3 μm as a thick intercoating layer 42.
Inorganic film such as 5102 or SOG with 0.2μ
Apply 0.51 tm of electron beam resist 43 on the upper layer.
A thick coating is applied, and approximately 100 aluminum layers 44 are deposited on top of it to prevent charge-up (Figure 4 (IL)).
). After exposure, remove the aluminum layer 44 with an alkaline aqueous solution,
Thereafter, it is developed (Fig. 4(b)).

Next, using this resist pattern as a mask, the intermediate layer 4 is
2 (FIG. 4(C)), and then, using the intermediate layer as a mask, the lower layer film 41 is dry etched (FIG. 4(d)). By using the multilayer resist process as described above, fine patterns can be formed with a high aspect ratio. However, the process is more complicated for multilayer resists that involve vapor-depositing aluminum layers, and
Problems such as contamination arise, making it impractical.

Problems to be Solved by the Invention As mentioned above, the multilayer resist process with an aluminum layer is an effective method, but there are problems such as complicated steps and aluminum contamination. Furthermore, a multilayer resist process in which the aluminum layer is removed has the problem of charge-up. Charge up is a resist where incident electrons are an insulator.

This is a phenomenon that accumulates in the middle or lower layer. This charge
The up effect causes major problems in electron beam ring graphing, such as field batting and deterioration of alignment accuracy. Furthermore, this charge-up phenomenon is also observed in single-layer resists, leading to field batting and deterioration of alignment accuracy, as with three-layer resists.

That is, in electron beam lithography, exposed electrons scatter through the resist without losing energy and stop at a depth of 1 to 1.5 μm from the resist surface, and charges accumulate in that region. It was thought that this accumulated charge would bend the electron beam, causing deterioration in field batting and alignment accuracy.

In order to solve these problems, the present inventors used electronically conductive polymers as electron beam resists and completed a method for forming fine patterns using them.

A means for solving the problem, that is, the present invention has the following general formula: (R1+R2, Rs, Ra are the same or different alkyl groups or alkoxy groups, and n is a positive integer.) The above-mentioned problems are attempted to be solved by using the polydiacetylene-based conductive polymer material shown above as an electron beam resist. This polymer material has a conjugated double bond in its main chain and exhibits high electrical conductivity.
Charge-up due to electrons can be prevented.

Further, since the triple bond is easily decomposed by the electron beam and causes a polymerization reaction, it can be used as a negative resist that exhibits high sensitivity to the electron beam.

In addition, the polyvinyl cyanide polymer material represented by the general formula: (where R represents an alkyl group and n represents a positive integer) does not exhibit electrical conductivity, but it can be changed by applying heat. , the following reaction progresses, and it comes to exhibit high electrical conductivity.

NN ↓ 5N10\N/”%N10chi/ This polymer material has a conjugated double bond in its main chain and easily undergoes a polymerization reaction with an electron beam, so it is a negative resist that exhibits high sensitivity to electron beams. It can become.

In addition, by using these electronically conductive polymer materials as the lower layer film of a multilayer resist, it is possible to easily form a multilayer resist, and it is possible to easily form a multilayer resist with accurate fine patterning without pattern shift due to charge up, field punting error, or alignment shift. A resist pattern can be formed.

Function The present invention uses the above-mentioned electronically conductive electron beam resist and resist process using the same to easily charge and release the resist.
Accurate fine patterns that do not cause close-up can be formed. In particular, there is no need to evaporate an aluminum layer, there is no problem of contamination, the process can be simplified, and charge-up due to electrons during electron beam writing can be prevented to form accurate fine patterns. I can do it. Therefore, by using the present invention, it is possible to effectively form accurate, high-resolution fine patterns.

Examples (Example 1) General formula: R-C3G-(,:C-R, where R is a urethane derivative group, 3-methyl-n
-butoxy-carbonyl-methyl-urethane (38CM
A polydiacetylene polymer was synthesized by dissolving U) in acetone and irradiating it with ultraviolet light. This polymer was dissolved in chloroform, and insoluble matter was filtered off to obtain a resist solution. This resist solution was applied onto a semiconductor substrate and heat treated to form a resist film with a thickness of 1.2 μm.

This resist film is applied with an acceleration voltage of 20 KV and a dose of 10 μc.
After electron beam exposure at /cm and development with a polar solvent, an accurate negative resist pattern without charge-up pattern -JTL or field putting error could be obtained.

(Example 2) After dissolving the polymer shown above in chloroform, the insoluble matter was filtered off and used as a resist solvent.

This resist solution was dropped onto the semiconductor substrate, and 2ooOr
After spin-coding with pm, baking was performed at 20C for 20 minutes to form a resist film with a thickness of 12 μm. This resist film was applied with an acceleration voltage of 20 KV and a dose of 10 μC.
After electron beam exposure at /, -, 4, and development with a polar solvent, it was possible to obtain an accurate negative resist pattern free of charge-up scratches and field batting errors.

(Example 3) A third example of the present invention is shown in FIG. A polymeric organic film is coated with a thickness of 2 μm as a lower layer film 11 on a semiconductor substrate 1.
Bake at 20°C for 20 minutes. On top of this, SOG was applied to a thickness of 0.2 μm as the intermediate layer 12, and
Perform baking for 0 minutes. On top of this, electron beam resist 1
3, the polymeric organic film obtained in Example 1 was
It was applied to a thickness of m and baked at 150C for 2Q minutes (
Figure 1 (1L)). Next, electron beam exposure was performed at an accelerated rate of tBE2oxv, "-sl 511C/pi, and development was performed with chloroform, resulting in an accurate fine negative resist pattern (Fig. 1 ('b)). Conductivity was so good that no pattern shift due to charge-up was observed.

Using this resist pattern as a mask, the intermediate layer 13 was etched (FIG. 1(C)). Furthermore, by etching the lower film 11 using the intermediate layer as a mask, it was possible to obtain an accurate and vertical fine resist pattern (FIG. 1(d)).

As described above, according to this example, by using this conductive polymer material as the upper resist layer of the multilayer resist, charge-up during electron beam exposure can be prevented and an accurate fine resist pattern can be formed. can do.

(Embodiment 4) A fourth embodiment of the present invention is shown in FIG. The polymer obtained in Example 2 was applied as the lower layer film 21 onto the semiconductor substrate 1, and baked at 250C for 20 minutes to form a 2 μmg film. On top of this, an intermediate layer 22 with an SOC of 0.
2μm thick coating and 200℃.

After baking for 20 minutes, polymethyl methacrylate (PMM) was applied as an electron beam resist 23 on top of the baking.
A) was applied to a thickness of 0.6 pm at 170°C.

Baking was performed for 20 minutes (FIG. 2(a)). Next, acceleration voltage 20K V dose amount 1o o ttc/
By performing electron beam exposure at t = 4 and developing with methyl isobutyl ketone (MIBK), it was possible to form an accurate fine resist pattern without field batting errors due to charge up (see Figure 2). b)
). Using this resist pattern as a mask, the intermediate layer was dry-etched (Fig. 2(C)), and the underlying film was further etched using the intermediate layer as a mask (Fig. 2(d)).
)). In this way, an accurate and vertical fine resist pattern could be obtained.

As described above, according to this example, by using this conductive polymer material as the lower layer film of the multilayer resist,
Charge-up during electron beam exposure can be prevented, and accurate fine patterns can be formed.

(Embodiment 6) A sixth embodiment of the present invention is shown in FIG. The polymer obtained in Example 1 was deposited on a semiconductor substrate 1 as a lower layer film 31 with a thickness of 2 μm.
It was coated thickly and baked at 250C for 2Q minutes.

A silicon-containing resist was applied thereon to a thickness of 0.3 .mu.m as an electron beam resist 32, and baked at 100.degree. C. for 20 minutes (FIG. 3(a)). Next, acceleration voltage 20K
V, electron beam exposure was performed at a dose of 10 μC/ca, and development was performed with isopropyl alcohol-1v.
An accurate resist pattern without pattern deviation due to charge-up was obtained (FIG. 3(b)). Using this resist pattern as a mask, the underlying film was etched, and an accurate and vertical fine resist pattern could be obtained (FIG. 3(C)).

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, for example, a conductive organic polymeric material, polydiacetylene.

When polyvinyl cyanide is used as an electron beam resist, a negative resist pattern with high sensitivity and high resolution can be formed. By using these resists, the influence of charge-up due to incident electrons is eliminated, and feed batting and alignment accuracy can be improved.

In addition, by using it as a lower layer film of a multilayer resist, charge-up can be easily prevented and accurate and vertical fine resist patterns can be formed.
It can greatly contribute to the production of ultra-high density integrated circuits.

[Brief explanation of drawings]

Fig. 1 is a process sectional view of an embodiment of the present invention, Fig. 2 is a process sectional view of an embodiment of the same song, Fig. 3 is a process sectional view of an embodiment of the invention, and Fig. 4 is a conventional multilayer It is a process sectional view of the resist method. 1... Semiconductor substrate, 11.21... Heavy lower layer film,
12.22...Mountain middle layer, ff 3, 23...
...Resist. Name of agent: Patent attorney Shigetaka Awano 1 person, 2 tons
-J) J limb 3f - 11th lower moon running 32 - 1st Ramata 33 - odd) ball J4---Register O-n

Claims (4)

[Claims] (1) General formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, R_1, R_2, R_3, R_4 represent the same or different alkyl groups or alkoxy groups, and n represents a positive integer.) A fine pattern forming material characterized by being made of a polydiacetylene polymer. (2) General formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, R represents an alkyl group, and n represents a positive integer.) Characteristic fine pattern forming material. (3) a step of applying a polymeric organic film on the semiconductor substrate and heat-treating it; a step of applying an inorganic film on the polymeric organic film and heat-treating it; and a step of applying a polydiacetylene-based polymer on the inorganic film, or A pattern forming method comprising the steps of applying and heat-treating a polyvinyl cyanide polymer, and etching an inorganic film and a high-molecular organic film using a resist pattern as a mask. (4) A step of applying a polydiacetylene polymer or a polyvinyl cyanide polymer on a semiconductor substrate and heat-treating it, a step of applying an inorganic film on the polymer film and heat-treating it, and a step of applying a resist on the inorganic film. The process of applying and heat-treating the
A pattern forming method comprising the steps of drawing a pattern, developing it, and etching an inorganic film and a polymer film using the resist pattern as a mask.