Computer circuit on Silicon Wafer
A wafer is a very thin, round slice of semiconductor material, such as a crystalline silicon, used in electronics for the fabrication of integrated circuits and in photovoltaics for conventional, wafer-based solar cells.
Here you can see the outlines of the circuits on the surface of the wafer. Each line is a little “wire” connecting one part of the chip to another. After fabrication, they will be cut up into individual computer chips.
This particular circuit is from an early 1990s Alcatel telephone system chip. This chip utilizes a much larger and less dense process than current computer chips. The newest chips have circuitry too small to easily visualize with a light microscope.