There is disclosed a method and apparatus for mounting a leadless semiconductor chip on a header. The semiconductor chip has contacts on a surface and the chip is of a specified geometric shape. The header has a contact surface for receiving the chip with the contact surface of the header containing header contact pins, which pins have to contact the contacts on the semiconductor chip. The header has a guide pin extending from the contact surface and there is a guide plate which has an aperture adapted to be placed over the guide pin, the guide plate further has a chip accommodating aperture of the same geometric shape as the chip. The guide plate, when placed over the guide pin enables the chip to be placed in the chip accommodating aperture so that the contacts of the header pin are properly and accurately aligned with respect to the contacts on the semiconductor chip.