If you have a square taper bottom bracket look to see if it has caused a dent in side of the crank arm. This is an indication or poor machining of the crank. If so use a round file to remove the deformed aluminum in the crank. Don't over do it. Replace the crank ride it a bit and repete the process. The lip of aluminum is preventing the crank from being tightened all the way causing the creaking.