§1. Those aspiring to the presbyterate can be promoted to the diaconate only after they have completed the fifth year of the curriculum of philosophical and theological studies.
§2. After a deacon has completed the curriculum of studies and before he is promoted to the presbyterate, he is to take part in pastoral care, exercising the diaconal order, for a suitable time defined by the bishop or competent major superior.
§3. A person aspiring to the permanent diaconate is not to be promoted to this order unless he has completed the time of formation.
Source: Code of Canon Law (Vatican.va)