A cleaning method for a turbo molecular pump, which enables the exhausting ability of the turbo molecular pump to be restored without bringing about a decrease in the productivity of a substrate processing apparatus. The method may be applied to error correction codes, including BCH codes, Reed-Solomon codes, turbo codes, and the like. Individual solder balls of the plurality of solder balls include a first solder material and a second solder material, the first solder material having a liquidus temperature that is greater than a peak temperature of the solder reflow process and the second solder material having a liquidus temperature that is less than the peak temperature of the solder reflow process.