Resist underlayer film forming composition for lithography, containing aromatic fused ring-containing resin

Abstract

There is provided a resist underlayer film forming composition for lithography, which in order to prevent a resist pattern from collapsing after development in accordance with the miniaturization of the resist pattern, is applied to multilayer film process by a thin film resist, has a lower dry etching rate than resists and semiconductor substrates, and has a satisfactory etching resistance relative to a substrate to be processed in the processing of the substrate. A resist underlayer film forming composition used in lithography process by a multiplayer film, comprises a polymer containing a unit structure having an aromatic fused ring, a unit structure having a protected carboxyl group or a unit structure having an oxy ring. A method of forming a pattern by use of the resist underlayer film forming composition. A method of manufacturing a semiconductor device by utilizing the method of forming a pattern.

Description

TECHNICAL FIELD[0001]The present invention relates to a resist underlayer film forming composition for lithography effective during processing a semiconductor substrate, a method of forming a resist pattern using the resist underlayer film forming composition, and a method for producing a semiconductor device.BACKGROUND ART[0002]Conventionally, in the production of a semiconductor device, fine processing by the lithography using a photoresist composition has been performed. The fine processing is a processing method including: forming a thin film of a photoresist composition on a substrate to be processed, such as silicon wafer; irradiating an activating light ray, such as an ultra violet ray onto the resultant thin film through a mask pattern in which a pattern of a semiconductor device is depicted to develop a photoresist pattern; and subjecting the substrate to be processed, such as silicon wafer to etching processing using the resultant photoresist pattern as a protecting film. ...

AI Technical Summary

Benefits of technology

[0046]The present invention relates to a resist underlayer film formed using a resin containing a polymer having an aromatic fused ring and to a resist underlayer film forming composition for forming the resist underlayer film.

[0047]By the resist underlayer film forming composition of the present invention, an advantageous pattern shape of a resist can be formed without causing intermixing with an upper layer part of the resist underlayer film.

[0048]To the resist underlayer film forming composition of the present invention, a performance of efficiently suppressing reflection from a substrate can be imparted and the composition can have an effect as a reflection preventing film for exposing light in combination with other functions.

[0049]By the resist underlayer film forming composition of the present invention, an excellent resist underlayer film having a selection ratio of the dry etching rate close to that of a resist, a selection ratio of the dry etching rate smaller than that of a resist or a selection ratio of the dry etching rate smaller than that of a semiconductor substrate, can be provided.

[0050]For preventing a resist pattern from collapsing after the development, the resist is thinned in accordance with the miniaturization of the resist pattern. For producing such a thin-film resist, there are a process in which a resist pattern is transferred to an underlayer film thereof through an etching process and a substrate processing is performed using the underlayer film as a mask; and a process in which a resist pattern is transferred to an underlayer film thereof through an etching process and further, the pattern transferred to the underlayer film is transferred to another underlayer film thereof using a different gas composition, is repeated and finally, a substrate processing is performed. The resist underlayer film and forming composition therefor of the present invention are effective for these processes and when a substrate is processed using the resist underlayer film of the present invention, the resist underlayer film has satisfactory etching resistance relative to a substrate to be processed (for example, a thermally-oxidized silicon film, a silicon nitride film, a polysilicon film and the like on a substrate).

[0051]On the other hand, for obtaining a fine resist pattern, a process for making a resist pattern and a resist underlayer film, during dry-etching a resist underlayer film, thinner than a pattern width during a resist development, has started to be used. The resist underlayer film and forming composition therefor of the present invention are also effective for this process and have a selectivity of the dry etching rate close to that of a resist.

Problems solved by technology

Following such a tendency, the influence of diffuse reflection of an activating light ray from the substrate or of a standing wave has become a large problem.

In future, when the miniaturization of the resist pattern progresses, there are caused a problem of the resolution and a problem of the collapse of the resist pattern after the development, so that the thinning of the resist becomes desired.

Therefore, it is difficult to obtain a film thickness of the resist pattern sufficient for processing the substrate and a process for imparting a function as a mask during processing the substrate to not only the resist pattern, but also a resist underlayer film produced between a resist and a semiconductor substrate to be processed, has become necessary.

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