Micro-wires bonded to silicon chip. Coloured scanning electron micrograph (SEM) of the ends of micro- wires bonded to the margin of a silicon chip. These micro-wires are made of gold, used as an excellent conductor of electricity. They link the integrated circuit of a silicon chip to pins by which the chip is connected to its external electronic environment, such as a computer circuit board. Magnification: x120 at 6x7cm size. Magnification: x220 at 4x5 inch size.