Patent ID: 7474106

Claim:
A method for testing a semiconductor device including: first and second power supply terminals; a measuring terminal; and at least one trimming detection circuit connected between said measuring terminal and one of said first and second power supply terminals, said trimming detection circuit including: a current supplying element; a series arrangement of a fuse and a switch element, said current supplying element and said series arrangement being connected in series between said measuring terminal and the one of said first and second power supply terminals; and a determination circuit having an input connected to a node between said current supplying element and said series arrangement and adapted to determine whether said fuse is in a connection state or in a disconnection state, a voltage at the other of said first and second power supply terminals being applied to said measuring terminal in a normal mode, said method comprising: turning ON said switch element; detecting a current flowing through said measuring terminal while said switch is turned ON; calculating a resistance value of said fuse in accordance with said current; and determining whether or not said fuse is in a connection state, in a complete disconnection state or in an incomplete disconnection state in accordance with the resistance value of said fuse; wherein said fuse resistance value calculating comprises: calculating a first resistance value of a circuit formed by said current supplying element, said fuse and said switch while said switch is turned ON before said fuse is disconnected; calculating a second resistance value of said circuit while said switch is turned ON after said fuse is disconnected; and calculating said resistance value of said fuse in accordance with a difference between said second resistance value and said first resistance value.