PROCESS METHOD OF GRAY TONE PHOTO MASK, GRAY TONE PHOTO MASK AND GRAY TONE BLANK MASK

摘要

Provided are a large-size gray tone blank mask and a gray tone photo mask in which position alignment of a transmission pattern, a semi-transmission pattern, and a light shielding pattern is precisely controlled by self-align of the gray tone photo mask, and preparing method of the gray tone photo mask. The large-size gray tone photomask is prepared by providing a gray tone blank mask comprising a first photoresist, a semi-transmitting layer(2) and a light barrier(3) sequentially deposited on a transparent substrate(1); forming a first photoresist pattern on the blank mask by exposing and developing; forming a semi-transmitting opening by etching the light barrier through the first photoresist pattern; removing the first photoresist and coating a second photoresist; forming a second photoresist pattern on the second photoresist by exposing and developing a part or the whole of the semi-transmitting opening; etching the light barrier through the second photoresist pattern; and etching the semi-transmitting layer through the second photoresist.