The Schengen visa application form uses "sponsor" in the following context:
- Cost of travelling and living during the applicant's stay is covered:
[ ] by the applicant himself/herself
[ ] by a sponsor (host, company, organization), please specify:
- [ ] referred to in field 31 or 32
- [ ] other (please specify)
Since you're not paying your own costs, you shouldn't check "by the applicant himself/herself", and thus whoever is actually paying should be put down as a sponsor. I would check "other", and explain the details in words on a separate sheet.
You'll want to attach some evidence of your father's economic situation which makes it plausible that he can and will fund your trip.
Apart from that, don't sweat it. As long as you're actually providing clear, complete and truthful information about the circumstances of your planned trip, and it doesn't look like you're trying to hide something, they're not going to refuse the application simply because you put the information in this field of the form rather than that.