1. A semiconductor device design system comprising a numerical value acquiring part, which acquires the numerical value of at least one calculation parameter, a junction estimating part that, in the case in which, between at least two substrates on which a plurality of terminals has been provided, the respective substrates are pressed at a prescribed pressure so that the front end faces of the respective mutually corresponding terminals come into contact, estimates whether or not the respective mutually opposing terminals will be respectively joined based on the numerical values of calculation parameters acquired by the numerical value acquiring part, and a change processing part which, in the case in which it has been estimated by the junction estimating part that any of the respective terminals will not be joined, gives a warning or performs processing so as to change the numerical value of at least one of the calculation parameters from among the calculation parameters acquired by the numerical value acquiring part.