Method of manufacturing semiconductor package

A method of manufacturing a semiconductor package, comprising:

• mounting a semiconductor chip on a first surface of a substrate;
• forming a plurality of pads on a second surface of the substrate opposite to the first surface;
• and
• forming a plurality of solder balls on the plurality of pads, respectively,
• wherein the forming of the plurality of solder balls comprises:
• estimating an error in a solder ball attaching process;
• determining a specification of a ball tool and a method of the solder ball attaching process, based on the estimated error;
• manufacturing the ball tool;
• performing the solder ball attaching process;
• and
• evaluating the ball tool,
• wherein according to the determining of the specification of the ball tool and the method of the solder ball attaching process, the substrate is divided into a first working region and a second working region, and the ball tool comprises a first holder on a first tool region corresponding to the first working region, and a second holder on a second tool region corresponding to the second working region, and
• wherein the estimating of the error in the solder ball attaching process comprises:
• calculating a first error, which is a tolerance in position of a solder ball;
• calculating a second error, which is a mean value of an offset between a sidewall of the substrate and a sidewall of the ball tool;
• and
• calculating a third error, which is a misalignment value between the substrate and the ball tool, which is caused by a driving error of the ball tool.