Became is the past tense of a word "Become."
Become- 1. begin to be.
2. Grow to be; develop into.
3. (Of a person) qualify or be accepted as.
4. (In questions) happen to.
5. (Of clothing) look good on or suit (someone).
6. Be appropriate to (someone)
Verb form: Become, Became, Become
The birthday party became more interesting.