Chemistry for liner removal in a dual damascene process

摘要: An improved and new process for fabricating dual damascene copper, in which trench/via liner removal from porous low-k dielectric, is performed using a RIE chemistry of CF4/H2, to etch SiN SiC liners. Prior the process, convention etching produced following deleterious results: a) Cu re-deposition by sputtering, b) polymer deposits, c) surface roughening IMD dielectric. Process details are: CF4/H2 based with approximate gas flow ratios greater than 10 1, hydrogen carbon tetra-fluoride. A nominal ratio 300 20, tetra-fluoride, or 15 was developed.