| 摘要 |
PURPOSE:To enable detection of a defect in a land pattern by contituting length measuring sensors consisting of total eight pieces including three pieces in a vertical direction, three pieces in a horizontal direction and two pieces in a diagonal direction and inspecting the land pattern by the combination of the length values measured by such sensors. CONSTITUTION:This sensor is constituted of total eight pieces of measuring length sensors including three pieces LL', YY', RR' in a vertical direction, three pieces UU', XX', DD' in a horizontal direction and two pieces FF', GG' in a diagonal direction. A circuit 1 corresponding to the specific equation is formed by determining the upper limit value for the size of leads so that the pattern larger than normal lead wires can be detected. Circuits 2, 3 corresponding similarly to the other specific equation to detect the center of lands and another specific equation to measure the length in the directions X, Y are respectively formed and the outputs therefrom are inputted together with the output from the circuit 1 to an AND circuit 4, by which a defect signal is obtd. |
