| 摘要 |
A phase shift mask including two phase shift film patterns formed on one or both surfaces of a transparent substrate such that their optical paths overlap with each other. On one of the phase shift film patterns, a phase shift film pattern having a space size smaller than that of the associated phase shift film pattern is formed, so that three phase shifts of light can be generated with reference to the phase shift film pattern, thereby causing an interference among adjacent light beams. Such a light interference results in an improvement in the image contrast and an increase in the gradient of the light intensity graph. As a result, it is possible to achieve an easy fabrication of micro patterns and an improvement in the process margin, operation reliability and process yield. The invention also provides a method for fabricating such a phase shift mask. |
