Patent ID: 7822566
Filing Date: 2010-10-26
Classification: H05K

Abstract:
1. A method of setting an optimum reference value for judging a measured value of a target portion for inspection of substrates having components mounted thereto after an intermediate process, said substrates being produced through a plurality of production processes inclusive of said intermediate process and a final process that is the last of said production processes, said method comprising the steps of: measuring each of target portions on a plurality of substrates of a same kind individually in a measurement process after said intermediate process is carried out, judging mounted condition of each component in a judgment process after said final process is carried out, and saving results of the steps of measuring and judging in a memory; repeating, after a step of initializing a reference value regarding target portions for inspection that use a reference value in common among said plurality of substrates, a process of calculating the number of substrates for which measured values within a range of NG meaning no good or OK meaning good have been obtained according to said reference value and for each of which a judgment of OK or NG has been respectively given in said judgment process after said final process, said process of calculating being repeated by varying said reference value; and setting said reference value as said optimum reference value when the ratio of said calculated number of substrates with respect to the total number of substrates for which said results are saved in said memory is within a preliminarily set allowable range of frequency of occurrence of disagreement in judgment in inspections after said intermediate process and said final process; wherein the step of initializing a reference value comprises, if no reference value has been set by a user, if no reference data indicate a reference value, and if said method is not being used for correcting an already set reference value, the steps of: retrieving out of said memory measured values obtained in said measurement process after said intermediate process regarding substrates for which judgment results of OK or NG were obtained in said judgment process after said final process on a target portion for which said reference value was used in common among said plurality of substrates; and defining as initial value of said reference value a measured value corresponding to a boundary position between a range in which said retrieved measured values are distributed and another range in which said retrieved measured values are not distributed; wherein the step of initializing a reference value comprises, if a reference value has been set by a user, the step of defining said reference value set by said user as initial value of said reference value; wherein the step of initializing a reference value comprises, if reference data indicate a reference value, the step of defining said reference value indicated by said reference data as initial value of said reference value; and wherein the step of initializing a reference value, if said method is being used for correcting an already set reference value, the step of defining said already set reference value as initial value of said reference value.