Depending on your jurisdiction and region, there are a variety of funding/subsidy opportunities available for Canadian employers to hire co-op students. However, all of these require pre-approval and cannot be claimed after the fact as any type of tax credit.
But in some jurisdictions, tax credits exist for apprenticeship situations and those can be applied retroactively.
Each jurisdiction has their own subsidy program, but you can access an overview at Wage subsidies and tax credits for employers (canada.ca)