content_image/913693.jpg content_image/913692.jpg
[Chem. 178] 

<img src='content_image/913693.jpg'>

## [Basic Compound] 

Basic compounds (Bl to B6) are as shown before. 

## [Organic Carboxylic Acid] 

Dl: 2-Hydroxy-3-naphthoic acid 

D2: 2-Naphthoic acid 

D3: Benzoic acid 

## [Surfactant] 

Surfactants (W-1 to W-3) are as shown before. 

## [Solvent] 

Solvents (Sl to S7) are as shown before. 

(3) Formation of Resist Film 

The resist coating solution was coated on the 6-inch wafer by using a spin coater, Mark 8, manufactured by Tokyo Elec› tron Ltd. and dried at 110° C. for 90 seconds on a hot plate to obtain a resist film having a thickness of 100 run. That is, a resist-coated mask blanks was obtained. 

( 4) Production of Negative Resist Pattern 

This resist film was patternwise irradiated using an elec› tron beam lithography apparatus (ELS-7500, manufactured by Elionix Inc., accelerating voltage: 50 keV). After the irra- diation, the resist film was heated at 120° C. for 90 seconds on a hot plate, dipped in an aqueous 2.38 mass % tetramethy› lammonium hydroxide (TMAH) solution for 60 seconds, rinsed with water for 30 seconds and dried. 

(5) Evaluation of Resist Pattern 

The obtained pattern was evaluated for the sensitivity, reso› lution, pattern profile, line edge roughness (LER), dry etching resistance, scum and aging stability by the following meth› ods. 

## [Sensitivity] 

The cross-sectional profile of the pattern obtained was observed using a scanning electron microscope (S-4300, manufactured by Hitachi, Ltd.), and the exposure dose (dose of electron beam irradiation) when resolving a resist pattern with a line width of 100 run (line:space=l: 1) was taken as the 60 sensitivity. A smaller value indicates higher sensitivity. [Resolution] 

The limiting resolution (the minimum line width below which the line and the space (line:space=l:1) were not sepa› rated and resolved) at the exposure dose ( dose of electron beam irradiation) giving the sensitivity above was taken as the resolution (run). 

<img src='content_image/913692.jpg'>

-continued 

## [Pattern Profile] 

The cross-sectional profile of a line pattern (LIS= 1/1) with a line width of 100 run at the exposure dose ( dose of electron beam irradiation) giving the sensitivity above was observed using a scanning electron microscope (S-4300, manufactured by Hitachi, Ltd.). The cross-sectional profile of the line pat› tern was rated "reverse tapered" when the ratio represented by [line width in the top part (surface part) of line pattern/line width in the middle ofline pattern (at the position of half the height of line pattern)] is 1.5 or more, rated "slightly reverse tapered" when the ratio above is from 1.2 to less than 1.5, and rated "rectangular" when the ratio is less than 1.2. 

## [Line Edge Roughness (LER)] 

A line pattern (LIS= 1/1) having a line width of! 00 run was formed with the irradiation dose ( dose of electron beam irra- diation) giving the sensitivity above. At arbitrary 30 points included in its longitudinal 50 µm region, the distance from the reference line where the edge should be present was measured using a scanning electron microscope (S-9220, manufactured by Hitachi, Ltd.). The standard deviation of measured distances was determined, and 3a was computed. A smaller value indicates better performance. 

## [Dry Etching Resistance] 

A resist film formed by performing entire surface irradia› tion with the irradiation dose ( dose of electron beam irradia› tion) giving the sensitivity above was subjected to dry etching for 30 seconds by using anAr/C$_{4}$FiO 2 gas (a mixed gas in a volume ratio of 100/4/2) in HITACHI U-621. Thereafter, the residual resist film ratio was measured and used as an indica› tor of dry etching resistance. 

Very good: Residual film ratio of95% or more. 

Good: Less than 95% and 90% or more. 

Bad: Less than 90%. 

## [Evaluation of Scum] 

A line pattern was formed by the same method as in [Pat› tern Profile] above. Thereafter, its cross-sectional SEM was obtained using S4800 (manufactured by Hitachi High-Tech› nologies Corporation), and the scum in the space portion was observed and rated as follows. 

C: Scum was observed and patterns were partially con› nected. 

B: Scum was observed but patterns were not connected. 

A: Scum was not observed. 

## [Aging Stability] 

Each composition was stored at room temperature over 1 month, and the degree of variation in the sensitivity (the sensitivity measured in [Sensitivity] above) between before and after the storage was evaluated. This evaluation was per› formed based on the following criteria. 

## (Criteria) 

A (Good): The variation in sensitivity was less than µC/cm2. 

B (Fair): The variation in sensitivity was 1 µC/cm 2 or more and 3 µC/cm 2 or less. 

