Why was the invention of the integrated circuit an important milestone?

Integrated circuits are etched onto a silicon chip. All the elements of a complete circuit can be included on a small slice of silicon, including transistors, resistors, capacitors and diodes. It takes several stages of a photographic and chemical process, to build up the design in a clean room to create a chip.

After the initial design, they can be mass produced at minimum material cost.

The chip is encapsulated in a small plastic box and legs sticking out, enabling it to be soldered onto a board with other chips and discrete components.

They are important to computers, as the miniturisation and complexity allows computers to be buit into a small enclosure at a reasonable price.