Bonding apparatus and bonding method

A bonding apparatus configured to bond a first substrate and a second substrate, comprising:

• a first holder configured to attract and hold the first substrate from above;
• a second holder provided below the first holder, and configured to attract and hold the second substrate under the first holder;
• a moving unit configured to move the first holder and the second holder relative to each other;
• a first transforming unit configured to make a central portion of the first substrate held by the first holder protrude downward;
• a second transforming unit configured to make a central portion of the second substrate held by the second holder protrude upward;
• and
• a controller and a storage storing a computer program, wherein the storage and the computer program are configured, with the controller, to control the moving unit, the first transforming unit, and the second transforming unit to perform a control of bringing the central portions of the first substrate and the second substrate into contact with each other such that the central portions of the first substrate and the second substrate are bonded to each other,
• wherein the controller performs:
• a control of changing a protruding amount of the central portion of the first substrate according to a protruding amount of the central portion of the second substrate,
• a control of decreasing the protruding amount of the central portion of the first substrate as the protruding amount of the central portion of the second substrate increases;
• and
• a control of changing a sum of the protruding amount of the central portion of the first substrate and the protruding amount of the central portion of the second substrate according to the protruding amount of the central portion of the second substrate.