JP2001264998A - Method for manufacturing semiconductor device and organic antireflection coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a semiconductor device so improved as to enhance productivity and reliability in the formation of a fine pattern. SOLUTION: An organic antireflection film 3 containing a light absorbing dye is formed on semiconductor substrates 1, 2 and a resist pattern 4a is formed on the antireflection film 3. The light absorbing dye in the antireflection film 3 is sublimed and the substrates 1, 2 are etched using the resist pattern 4a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a method for manufacturing a semiconductor device, and more particularly, to a method for improving the etching rate of an antireflection film and facilitating the formation of a fine pattern. And a method of manufacturing a semiconductor device improved in the above. The present invention also relates to an organic antireflection coating composition improved so that the etching rate of the antireflection coating can be improved and the formation of a fine pattern can be facilitated.

[0002]

2. Description of the Related Art In manufacturing a semiconductor device, a fine pattern is formed by performing photolithography.
In photolithography, a photosensitive photoresist applied to a chip or substrate is exposed and developed through a mask pattern on which a circuit pattern is drawn, a resist pattern is formed, and the shape of this pattern is transferred to the chip or substrate. It is a process for doing.

[0003] Because patterns are becoming finer, it is becoming difficult to transfer patterns by photolithography simply by shortening the wavelength of exposure light. One of the factors that hinder the pattern formation is halation due to a step on a base substrate on which a photoresist is applied. The surface condition of the underlying substrate is also a factor. Further, a halation from a lower layer pattern of a substrate having a multilayer structure may cause a defect in a resist pattern. Therefore, in order to transfer the resist pattern according to the mask on which the circuit pattern is drawn, it is important to suppress reflection from the base.

Therefore, it has been proposed to form an antireflection film layer using an organic material between a photoresist and a base substrate in order to suppress reflection from the base.

FIG. 5 is a cross-sectional view of a semiconductor device in each step of a conventional method of manufacturing a semiconductor device using an organic antireflection film.

Referring to FIG. 5A, a film 2 to be etched is formed on a base substrate 1. An organic antireflection film composition is applied on the film to be etched 2 by spin coating or dip coating to form an organic antireflection film 3.

Next, a positive or negative photoresist composition is applied on the organic antireflection film 3 by spin coating or dip coating to form a photoresist 4.

Referring to FIG. 5B, in order to transfer the pattern of the mask 5 to the photoresist 4, the mask 5 is arranged at an appropriate position on the pattern forming region on the substrate 1, and By irradiating light 6 having an appropriate wavelength such as UV light, a pattern forming region of the photoresist 4 is selectively exposed.

At this time, the light reflected from the film quality of the base substrate, the steps, and the lower layer structure is absorbed by the organic anti-reflection film 3, and photolithography having little dependence on the state of the base can be performed.

Referring to FIG. 5C, the photoresist is developed using an alkaline developer. by this,
A resist pattern 4a is formed. This conventional example is an example using a positive type photoresist, and the exposed portion 7 becomes alkali-soluble. When using a negative photoresist,
Conversely, the unexposed portions become alkali-soluble.

Referring to FIG. 5D, a desired pattern can be obtained by etching the organic antireflection film 3 and the film 2 to be etched in the opening portion using the resist pattern 4a as a mask.

[0012]

In the conventional method, FIG.
Referring to (c) and (d), since the difference in the etching resistance between the photoresist 4 and the organic anti-reflection film 3 against dry etching is small, the resist pattern 4a is It was etched in the horizontal direction and it was very difficult to obtain the desired pattern and dimensions.

The organic antireflection film 3 mainly comprises a base resin, a light absorbing dye, a solvent, and a surfactant. The organic antireflection film 3 is formed on the substrate 1 by spin coating or dip coating.

The light absorbing dye may be contained in the main chain of the base resin, may be present as a side chain of the resin, or may be present as a monomer in the solution.

In the case of lithography using KrF light, since anthracene has an absorption at a wavelength near KrF light, an absorbing dye having an anthracene derivative as disclosed in JP-A-8-62835 is used. Is often done.

The etching rate of the organic antireflection film 3 needs to be as high as possible with respect to the etching rate of the photoresist 4 formed thereon.

Generally, the etching rate of an absorbing dye such as an anthracene derivative shown in FIGS. 2A and 2B, which is used as a KrF light absorbing dye, is much smaller than that of a base polymer. It is. When etching an organic anti-reflective film containing a dye having a low etching rate and forming a fine pattern,
It is necessary to increase the difference in the etching rate between the photoresist 4 and the organic antireflection film 3.

Since the absorbing dye has the effect of suppressing reflection from the surface of the film to be etched and the lower layer, reducing the amount of the absorbing dye added to the components of the organic antireflection film 3 reduces the antireflection effect. And make the formation of a fine pattern difficult.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a semiconductor device improved so that a fine pattern can be easily formed.

Another object of the present invention is to provide an organic antireflective coating composition improved so that formation of such a fine pattern can be facilitated.

[0021]

According to a first aspect of the present invention, an organic anti-reflection film containing a light absorbing dye is formed on a semiconductor substrate. A photoresist film is formed on the semiconductor substrate with the organic antireflection film interposed. The photoresist is patterned to form a resist pattern. The light absorbing dye in the organic antireflection film is sublimated. The semiconductor substrate is etched using the resist pattern.

In the method for manufacturing a semiconductor device according to the second aspect, the organic antireflection film containing a base polymer to which anthracene methanol is chemically bonded is used.

According to a third aspect of the present invention, an anthracene methanol is further added as an additive to the base polymer.

The organic anti-reflective coating composition according to claim 4 comprises:
Includes base polymer with anthracene methanol chemically bonded.

In the organic antireflection coating composition according to the fifth aspect, anthracene methanol is further added to the base polymer as an additive.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

Referring to FIG. 1A, a film 2 to be etched is formed on a base substrate 1. On the film to be etched 2, an organic anti-reflection film 3 containing a light absorbing dye is formed. Photoresist 4 is formed on film 2 to be etched with organic antireflection film 3 interposed.

Referring to FIG. 1B, the photoresist 4
Is exposed with exposure light 6 using a mask 5.

Referring to FIG. 1C, the photoresist 4
Is developed to form a resist pattern 4a.

Referring to FIG. 1D, the organic antireflection film 3
Sublimates the light absorbing dye inside. In the figure, reference numeral 8 denotes a portion where the dye has sublimated.

Referring to FIGS. 1D and 1E, the organic antireflection film 3 and the film 2 to be etched are etched using the resist pattern 4a.

According to the present invention, referring to FIG. 1D, after the resist pattern 4a is formed, baking is performed to sublimate the dye having a low etching rate in the organic antireflection film 3. In addition, the etching rate of the organic antireflection film 3 is improved. Therefore, the etching rate of the organic antireflection film 3 is improved. As a result, the resist pattern 4a is not etched in the horizontal direction, and a desired pattern and dimensions can be obtained.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

A vinyl resin is used as a base polymer of the organic antireflection film. Here, an acrylic resin is used.
As a solvent or a carrier, a cyclic ketone such as cyclohexanone or cyclopentanone having a low surface energy is used in order to improve coatability.

Referring to FIG. 3, anthracene methanol shown in FIG. 2 (b) is bonded to the polymer as an absorbing dye of the organic antireflection film. The mode of the bond is an ester bond or an ether bond. Since the binding energy of anthracene methanol to the polymer is low, anthracene methanol can be easily sublimated.

Referring to FIG. 1A, the underlying substrate 1 is made of WS
The film 2 to be etched is a tetraethoxysilane film (TEOS).

The formation of the organic antireflection film 3 on the substrate 1 is usually performed by spin coating, dip coating or other methods, and is applied to the substrate 1 with a uniform film thickness.

Referring to FIGS. 1B and 1C, an organic anti-reflection film 3 composed of the above three components is formed, and a KrF excimer resist SEPR-407 manufactured by Shin-Etsu Chemical Co., Ltd. is applied thereon. Is performed to form a fine pattern 4a of 1: 1 Line & Space in which exposed portions and unexposed portions of about 0.30 μm are alternately repeated.

When the conventional method is used, since the etching rate of the organic anti-reflection film is small, the selectivity of the photoresist or the like is small, and the resist pattern 4a can be narrowed in the horizontal direction as shown in FIG. There is.

On the other hand, according to the present embodiment, referring to FIG. 1D, baking for sublimating the dye in the organic antireflection film 3 is performed after photolithography.

FIG. 4 is a graph showing a change in the etching rate. The horizontal axis represents the baking time, and the vertical axis represents the etching rate. □ indicates the case where baking was performed at 60 ° C., and Δ indicates the case where baking was performed at 180 ° C.

Referring to FIG. 4, when baking is performed at 180 ° C./120 seconds, the etching time is reduced by about 20%. As a result, referring to FIG. 1E, the dimensional fluctuation before and after the etching was reduced from 30 nm in the past to 24 nm.

It has been found that when the anthracene methanol monomer shown in FIG. 2B is added to the organic antireflection film, the dye is further easily sublimated.

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0045]

As described above, according to the first aspect of the present invention, since the step of sublimating the absorbing dye of the organic anti-reflection film is included, the etching rate of the organic anti-reflection film is increased, and the etching time is further increased. The dimensional variation between photolithography and etching is reduced. Thus, there is an effect that productivity and reliability can be improved in forming a fine pattern such as a semiconductor.

According to the second aspect of the present invention, the dye having a low etching rate can be easily sublimated by baking.

According to the method of manufacturing a semiconductor device according to the third aspect, since anthracene methanol is further added to the base polymer as an additive, sublimation becomes easier.

According to the organic anti-reflective coating composition of the fourth aspect, since the anthracene methanol contains the base polymer chemically bonded, the dye having a high etching rate can be easily sublimated. Is obtained.

According to the organic anti-reflective coating composition of the fifth aspect, since anthracene methanol is further added to the base polymer, a dye having a high etching rate can be more easily sublimated. become able to.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a semiconductor device in each step in an order of a method of manufacturing a semiconductor device according to an embodiment.

FIG. 2 shows the structures of anthracene and anthracene methanol.

FIG. 3 is a view showing a chemical formula of a base polymer to which anthracene methanol is chemically bonded.

FIG. 4 is a diagram showing a relationship between a baking time and an etching rate.

FIG. 5 is a cross-sectional view of a semiconductor device in each step of a sequence of a conventional method of manufacturing a semiconductor device.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 base substrate, 2 etched film, 3 organic antireflection film, 4 photoresist, 5 mask, 6 ultraviolet light, 8
The part where the dye sublimated.

Claims (5)

[Claims] A step of forming an organic anti-reflection film containing a light absorbing dye on a semiconductor substrate; a step of forming a photoresist on the semiconductor substrate with the organic anti-reflection film interposed; Patterning a photoresist to form a resist pattern; sublimating the light absorbing dye in the organic anti-reflection film; and etching the semiconductor substrate using the resist pattern. A method for manufacturing a semiconductor device. 2. The method according to claim 1, wherein the organic antireflection film includes a base polymer to which anthracene methanol is chemically bonded. 3. The base polymer further comprises anthracene methanol as an additive.
A method for manufacturing a semiconductor device according to claim 1. 4. An organic anti-reflective coating composition comprising a base polymer to which anthracene methanol is chemically bonded. 5. The organic anti-reflective coating composition according to claim 4, wherein anthracene methanol is further added to the base polymer as an additive.