has a thickness of about 0 25 u03bcm next the wafer coated with the resist solution was pre baked at a temperature of about 120 u00b0 c for about 60 seconds and then the pre baked wafer was exposed to light by using an arf stepper 0 6na u03c3 0 75 next a post exposure bake peb process was performed with respect to the exposed wafer at a temperature of about 120 u00b0 c for about 60 seconds after the peb process the wafer was developed by using a 2 38 wt of tetramethylammonium hydroxide tmah solution for about 60 seconds further a top photoresist pattern of 160 nm line space could be obtained with about a 15 mj cm 2 dose a mechanism illustrating how the photosensitive polymer iv is changed when exposed to light is shown by the following reaction equation before the photosensitive polymer shown above is exposed to light the photosensitive polymer is shown comprising a third monomer p having a si group after the photosensitive polymer is exposed to light the si group of the third monomer is substituted with hydrogen thereby forming a carboxyl group which is hydrophilic thus the photosensitive polymer with the carboxyl group can be readily dissolved in a developing solution the photosensitive polymer formed above represents an improved top photoresist over a conventional top photoresist in a blr photolithography process whose light sources are krf u03bb 248 nm arf u03bb 193 nm and f2 u03bb 157 nm excimer lasers the present embodiment illustrates a method for forming a silicon nitride pattern by using.