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## Comparative Example 401 and Examples 401 to 409 

A substrate was spin-coated with a resist composition in a thickness of 50 nm. The resist composition was AZfi AX2110 (manufactured by AZ Electronic Materials (Japan) K.K. ). After the resist composition was cast on the substrate, the resist was heated at 120° C. for 60 seconds to form a resist layer. Thickness of each of the resist layer thus formed was measured. 

Further, each of the compositions for forming a topcoat layer as shown in Table 4 was cast thereon by spin-coating in a thickness of30 nm. The layered compositions were then heated at 120° C. for 60 seconds to obtain a resist layer covered with a topcoat layer. The resist layer thus obtained was subject to development with a 2.38 wt % TMAH aqueous solution to remove the topcoat layer. Thereafter, thickness of the layer left was measured. 

The above measurement was repeated twice to thereby evaluate the loss of thickness caused by development. The results are shown in Table 4. 

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Although loss of thickness was somewhat higher in examples with a topcoat layer than in the example without a topcoat layer, such loss is not deemed to impede practi› cality. 

By way of summation and review, resist compositions sensitive to light in various wavelength ranges have been developed. Commercially available chemically amplified resist compositions have been considered for use in a photo-lithographic process with extreme UV light. For example, resist compositions for KrF or ArF laser exposure have been considered for use in a lithographic process including exposure to extreme UV light. However, resolu› tion, sensitivity, and roughness such as line width roughness (LWR) and line edge roughness (LER) may merit attention. 

Further, light sources and masks in exposure apparatuses may merit attention. As such, lithography techniques with extreme UV light have not yet been widely employed in practice. It has been thought that resist pattern shapes are impaired by longer wavelength light, for example, deep UV light of, for example, 193 nm or 248 nm, contained in emission from extreme UV light sources. When resist com- positions for KrF or ArF laser exposure are used as described above in a lithographic process with extreme UV light, they are made to sensitively react not only to extreme UV light, but also to deep UV light in a longer wavelength range than extreme UV light. 

Extreme UV light sources may emit extreme UV light together with longer wavelength light, such as deep UV 

light. A fine pattern may be intended to be formed according to a lithographic process by use of extreme UV light, and a light source emitting less of such deep UV light may be used. The method of generating extreme UV light may be controlled, and deep UV light may be removed from radia› tion emitted by exposure apparatuses. For example, optical systems in the apparatuses may be regulated so as to remove deep UV light from emission of light sources. It may be difficult to remove deep UV light completely from emission of conventional light sources, e.g., to reduce the ratio of deep UV light down to 3% or less in exposure light. Deep UV light contained in emission from extreme UV light sources may cause impairment of resist patterns in view of rough- ness and pattern shape. 

The top surface of a resist layer may be coated with a topcoat layer that transmits extreme UV light and absorbs deep UV light. Consideration has been given to polymers that may absorb deep UV light enough to be usable for the topcoat layer. The polymers may include benzene, naphtha- lene or anthracene skeletons. 

Provided is a composition for forming a topcoat layer containing a graphene derivative having a hydrophilic group, and a solvent, the topcoat layer absorbing deep UV light. The topcoat layer may reduce unfavorable effects of deep UV light, may help protect a resist pattern from impairment in roughness and in pattern shape, and may help prevent a resist layer from releasing gases in a photolitho› graphic process for pattern formation including exposure to extreme UV light. The composition may be provided on a resist layer before the resist layer is exposed to extreme UV light for producing a resist pattern in a photolithographic process. The topcoat layer may achieve a greater deep UV light absorbance. A minute pattern may be produced accu› rately. The composition for forming a topcoat layer may reduce residue remaining after development on the surface of a resist pattern and may contribute to excellent pattern formation. Also provided is a pattern formation method using the composition for forming a topcoat layer. 

Example embodiments has been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, as would be apparent to one of skill in the art as of the filing of the present application, features, characteristics, and/or ele- ments described in connection with a particular embodiment may be used singly or in combination with features, char› acteristics, and/or elements described in connection with other embodiments unless otherwise specifically indicated. Accordingly, it will be understood by those of skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims. 

What is claimed is: 

1. A composition for forming a topcoat layer, the com- position comprising: 

a graphene derivative including a hydrophilic group; 

a solvent; and 

a binder including a deep-ultraviolet absorbing group, 

wherein: 

the graphene derivative is present in an amount of about 0.5 to about 10 wt % based on a total weight of the composition, 

the binder is present in an amount about 0.01 to about 10 wt % based on a total weight of the composition, 

the graphene derivative and the binder are present in a weight ratio of about 30:70 to about 50:50 in the composition, and 

