Do any of you guys do what to use as a backboard for the new rim im gonna buy?

the rim is official is 18 long like nba hoops and do you guys know what sumthing strong enough to hold it and im gonna hang it to the wall and i want a backboard so i can do banks and will cardboard be strong enough or is there sumthing better and so i can hang it on the wall with the rim and the rim has screws