Patent ID: 7704646

Claim:
A half tone mask comprising: a transparent substrate; a light shield layer formed on the transparent substrate, and having light transmission portions completely transmitting irradiated light in a designated wavelength range and light shield portions completely shielding the irradiated light in the designated wavelength range; and light semitransmission portions partially transmitting the irradiated light in the designated wavelength range and made of one selected from the group consisting of Cr x O y , Cr x Co y , Cr x Co y N z and Si x N y , wherein x, y and z are natural numbers and denote numbers of respective chemical elements, and wherein the half tone mask is configured to simultaneously form two or more patterns in separate layers, which include: an active layer, a source/drain layer, a passivation layer, and a pixel layer of a thin film transistor (TFT) for a liquid crystal display (LCD).