Hi Anji,
I believe this can be achieved through the iterator class of your table view. Take the iterator class of your view. It will have a method called IF_HTMLB_TABLEVIEW_ITERATOR~RENDER_CELL_START. In this method, go to the case for your field. WHEN 'Field_name'. There is an attribute called 'TOOLTIP' for class CL_CRM_IC_LABEL. So take your field and give that label with custom field.
I haven't tried this yet. But as per me it should work for your purpose.
Thanks,
Faisal