低陡度光刻胶光栅槽形研究

Research on Acquisition of Low Gradient Photoresist Gratings

为控制全息光刻胶光栅槽形,从研究显影时间、显影液温度等对光刻胶特性曲线的影响出发,采用计算机模拟和实验方法,制作出底部占宽比30%左右,陡度65°左右的低陡度光刻胶光栅掩模.研究发现:启动曝光量随显影时间的延长而减小,光刻胶特性曲线线性部分的斜率随着显影时间的增加而增加;显影液温度高的光刻胶启动曝光量大,其特性曲线线性部分的斜率也较大.这决定了制作低陡度光刻胶光栅掩模需要使用非1∶1的干涉曝光,以及必须采用较低温度的显影液进行显影处理.最终选用1∶7的干涉曝光和15℃的显影液.

The control of the profile of holographic photoresist gratings is investigated. Considering the effects of developing time and temperature of the developer on the response of photoresist, the 1 ： 7 interferential exposure and 15 ℃- development have been adopted. A low gradient photoresist grating：30% duty cycle at bottom and 65° gradient can be fabricated. The result indicates that the increase of the developing time causes the decrease of the threshold volume of exposure while the increase of the slope of the linearity of photoresist response, and the rise of the temperature of the developer leads to both the increase of the threshold volume of exposure and the slope of the linearity of photoresist response. As a result non-1 ： 1 interferential exposure and low-temperature development are required in the fabrication of low gradient photoresist grating masks.