A method of aligning electronic components comprising providing a positioning member 110 having at least one formation 120 for receiving an electronic component; said at least one formation having lateral boundaries 35, 36 for constraining movement of an electronic component; placing a first electronic component 10a in said at least one formation; and providing a force for actively aligning said first electronic component with a lateral boundary of said at least one formation. The force may, for example, be provided by tilting the positioning member, by providing suction or by using an actuator. An apparatus for aligning electronic components and a 3D system of stacked electronic components is also disclosed.