As each of the previous posters has noted, every diocese has its own formation program, but in general, no, the deacon’s formation is not a seminary program. While there are similarities, and some of the classes (scripture, theology, specific ministerial classes like grief ministry, etc.) may even be the same, the candidate is in formation to be a
deacon, not a priest, and there are differences. For one, most candidates in a diaconate formation program have full-time jobs and families to care for. This does not necessarily mean that the deacon’s formation is any less than the priests’, only different (at least, it *should *not be less).
You can find a good version of the Basic Norms for the Formation and Life of Permanent Deacons
here. If you really want to know what it might be like though, ask a deacon in your diocese, or contact the chancery office of your diocese and they will point you to a resource (usually the vocations office).
Dcn. Jim Pearce