iPhone, half of the screen broken, cannot perform backup
Solution 1:
- Connect your iPhone with a Mac(that is trusted by your iPhone) using USB cable.
- open iTunes.
- Select your iPhone.
- Select the Backup method to your iCloud account or This Computer.
It will not ask for any passcode, but if it does, you could enter it using a Bluetooth keyboard.
Note: I am not sure if a not trusted Mac or PC connected it will work. Also See the attached image.