| 摘要 |
<p>PURPOSE:To make it possible to control a phase shift angle with high accuracy and to provide good transmittability and sufficient resistance to liquid chemicals, acids, etc., by constituting an etching stopper layer of a layer mainly composed of hafnium oxide. CONSTITUTION:The layer mainly composed of the hafnium oxide is formed as the dry etching stopper layer 202 on an optically polished glass substrate 201. A sputtering method, vacuum vapor deposition method, ion plating, etc., which are the conventional thin film forming techniques are utilized in order to form the hafnium oxide layer 202. In this sputtering method, a target mainly composed of metal hafnium or an oxide of the hafnium is used and a substrate is exposed to the plasma formed by maintaining an atmosphere combined with gas to serve as an oxygen source under an adequate pressure and turning on a DC or high-frequency power source. Then, the phase shift angle is controlled with the high accuracy and the transmittability to (i) line of a mercury lamp and KrF excimer laser beams is improved.</p> |
