The EECS Department has no involvement with undergraduate financial aid or with the Office of Financial Aid. Undergraduate scholarships typically last until the end of the eighth semester of UG work, or until you graduate with your BS degree (whichever comes first). The Office of Undergraduate Studies will require you to graduate with your BS as soon as you have completed all your undergraduate degree requirements. You can use your undergraduate financial aid until it expires. A few students who entered with advanced placement credit or who have taken extra courses each semester have managed to complete their BS/MS requirements in four years.
There are a few external programs that provide financial aid for the MS degree. Please check the EECS Department Website for links to financial aid programs which may be applicable.