Sharp Edge Profiles Research Articles

ソフトウェアデータムによる段差形状の測定

It is important for precision profile measurements on on-machine conditions to construct some accurate datum for scanning. Any preceding method using software datum is not possible to measure step-wise profiles accurately. In the inclination method, it is necessary to hold some distance between two displacement sensors and in most cases the distance is too wide to represent a sharp edged stepwise profile. The generalized 3-probe method and other methods using software datum can represent more higher frequency components than the inclination method. However the shape of step can not yet be expressed because of Gibbs's phenomenon in the Fourier transform which is used for deconvolution. In the present paper it is proposed to combine the inclination method and 2- or 3-probe method. The new method determines the relative height between the discrete data groups of the inclination method by using generalized 2- or 3-probe method. And the new combining method can maintain the advantage of the inclination method that the discrete data present rigorously the original relative height of sampled points without any errors of data processing.

High performance electron negative resist, chloromethylated polystyrene. A study on molecular parameters

AbstractHigh sensitivity and high contrast electron negative resist, chloromethylated polystyrene (CMS) was developed for direct writing electron beam lithography with 1‐μm resolution. The resist shows excellent lithographic performances such as high plasma‐etching durability and negligible “post polymerization effect”. A series of CMS covering a wide range of M̄w, 6,800–560,000, were synthesized by the chloromethylation of nearly monodisperse polystyrenes. The effects of molecular parameters on sensitivity and resolution were investigated. The chloromethylation remarkably improved the reactivity of polystyrene, but which was saturated above 40% of chloromethylation ratio. About 100 times higher sensitivity could be achieved as compared with the starting material. As the increase of chloromethylation ratio (CR) gradually broadened the molecular weight distribution (MWD), the optimum CR was evaluated to be about 40%. In the above range of M̄w, the sensitivity varies from 39 to 0.4 μC/cm, whereas the γ‐value varies from 3.0 to 1.4. A sharp edge profile was obtained in developed pattern of CMS resist because of its relatively high glass‐transition temperature (68–115°C) compared with commercial resists and the suitable selection of a developer. The resolution of CMS was compared with the structually related polymers synthesized from polystyrene with a broader MWD or vinylbenzylchloride and poly(chloroethylvinylether) (CEVE). These polymers show significantly lower resolution than CMS, which indicates the importance of MWD and Tg in electron negative resist.