- Missing ball
- Condition
Misplaced the solder balls.
Primary cause
- Solder balls are not placed at the mounting process.
- Lack of solder ball retention due to lacking or unfilled during printing flux process.
- Lack of solder ball retention due to insufficient flux tack.
Solution
- Mount the solder balls properly.
- Optimize the printing conditions to prevent the insufficient or unfilled of flux.
- Increase the tackiness of the flux to hold the solder balls in place to prevent them from moving.
