You cannot apply for a super visa until you officially have PR. To qualify to sponsor your mother for a super visa, you must be making enough income to meet the Low Income Cut Off (LICO) level for super visas. If you are not making enough income to meet the minimum, then the only option at this time is for your mother to apply for a regular visitor visa.
To ensure she can get a super visa, you must be making enough money to meet LICO, your mother must pass the medical and your mother must also provide evidence that she has strong ties to her home country and has no plans on remaining in Canada long term. A super visa can still be refused for the same reasons as a regular visitor visa (e.g. purpose of visit and lack of travel).