SK hynix developed alternative gases which proved effective in some processes, expecting to reduce by 73% of scope 1 emissions until 2050. An altered gas(GWP below 1) is able to replace NF3 used at a chamber cleaning process and bring higher cleaning efficiency in wafer level. We also lowered process gases usage called the process optimization. The more the number of optimization cases, the larger amount of GHG emissions has been reduced during recent several years, resulted in reduction of 12,029 tons in 2022.