Recent bottom layered half-tone mask blanks development for large sized and high resolution flat panel displays

Half-tone masks are essential for process reduction and shape control of photo reactive organic material in FPD, the importance of half-tone masks is increasing in recent large sized and high resolution displays. Half-tone masks are categorized as top layer type and bottom layer type. Process reduction and short term mask production are possible in bottom layer half-tone mask. Therefore it is expected that the demand of bottom layer half-tone mask will be increasing in future. Ulvac coating has developed two types of bottom layer half-tone mask blanks which half-tone layers are composed in Cr material or MoSi material respectively. Since each bottom layer half-tone mask blanks has different advantage in process and characteristics, it is possible to select half-tone mask blank by customer requirement. We will discuss process and characteristics of two types bottom layer half-tone mask blanks in this meeting.