>  is there a way to remove sticky adhesive, which is left over after a
>  cellotape is removed. we are using cello tape for masking while etching
>  SiN, and when cellotape is peeled of the sticky glue is left over. Is there
>  a better way to remove it with out scrubbing?

It depends on the type of glue.  Try IPA, extraction naphtha or benzine.
Sometimes acetone is enough.