Method for manufacturing semiconductor device

A method for manufacturing a semiconductor device, comprising:

• aligning a first solder bump provided on a first substrate and a second solder bump provided on a second substrate;
• contacting the first solder bump and the second solder bump while controlling a load applied to the first and second solder bumps by a load detector;
• melting the first and second solder bumps by heating to a temperature equal to or higher than a melting point of the first and second solder bumps while maintaining a height of the first solder bump and the second solder bump which are in contact with each other, to form a partial connection body of the first solder bump and the second solder bump;
• deforming the first and second solder bumps in a melted state by adjusting a distance between the first substrate and the second substrate while controlling the height of the first solder bump and the second solder bump in the melted state by a height controller, wherein oxide films existing on surfaces of the first and second solder bumps are moved to a side face of the partial connection body at a time of deforming the first and second solder bumps in the melted state;
• cooling the partial connection body;
• and
• heating the partial connection body after the cooling to a temperature equal to or higher than the melting point of the first and second solder bumps in a reducing atmosphere, to form a permanent connection body by melting the partial connection body while removing the oxide film existing on the side face of the partial connection body.