Screen printing apparatus and screen printing method

A screen printing method for collectively printing a soldering paste on electrodes for connecting electronic components, which are formed on individual substrates, with respect to a plurality of individual substrates held on a carrier, by a screen printing apparatus,

• wherein the screen printing apparatus comprises:
• a mask plate provided with pattern holes corresponding to the electrodes;
• a positioning device for two-dimensionally positioning the carrier with respect to the mask plate based on positioning parameters;
• a squeegee for printing a soldering paste on the electrodes via the pattern holes by executing a squeegeeing motion in sliding contact with the mask plate;
• and
• a print inspection portion for detecting a position of the soldering paste printed on each of the individual substrates and detecting positional deviation of the soldering paste with respect to the electrodes as soldering position deviation data indicating a positional deviation quantity for each electrode;
• and
• a feedback data supplying step for supplying feedback data to improve a positional deviation state based on statistical data of positional deviation for individual substrates, in which the positional deviation quantities are statistically processed for each individual substrate, comprising the steps of:
• obtaining a plurality of average values of individual positional deviation quantities from the soldering position deviation data which indicate an average value of the positional deviation quantity for each individual substrate;
• comparing a deviation value indicating a difference between a maximum value and a minimum values of the average values of positional deviation quantities with tolerance values predetermined in advance;
• and
• carrying out a calculation for supplying feedback data, by which a mean value of the maximum value and the minimum value is obtained, if the deviation value is less than or equal to the tolerance value, and
• updating the positioning parameters based on the mean value.