Front-end

Notes

Confusingly, front-end in design conversations means RTL and verification, while front-end in manufacturing means the fab.

Overview

In the semiconductor value chain, the front end is wafer fabrication: everything from a bare wafer to a finished, patterned wafer, including building the transistors and the wiring above them in the cleanroom. It is where most of the industry's capital is spent, and its capacity is measured in wafer starts. Assembly, packaging and test that follow are called the back end.

How it works

A front-end fab takes polished wafers and repeats cycles of deposition, lithography, etch, ion implantation, cleaning, polishing and measurement hundreds of times. The first part of this flow builds the transistors and the second builds the layers of metal wiring that connect them. At the end, wafers are usually tested at wafer sort, then shipped to an assembly site.

The front end is far more capital intensive than the back end. A 2021 SIA and BCG study estimated that a state-of-the-art fab of standard capacity costs roughly 5 billion dollars for advanced analogue to 20 billion dollars for advanced logic and memory, and that wafer fabrication accounted for about 65% of the industry's capital spending and 25% of its value added. Companies focused on manufacturing typically spend 30 to 40% of their revenue on capital.

Front-end manufacturing is done by integrated device manufacturers in their own fabs and by foundries for fabless and other customers. Its location is concentrated mainly in East Asia, which has made fab investment a focus of government industrial policy around the world.

Examples

• A leading-edge logic fab processing wafers through hundreds of steps over several months.
• A fabless company buying front-end capacity from a foundry and back-end services from an assembly house.
• A government incentive programme funding new front-end fabs to diversify supply.
• A memory maker expanding front-end capacity measured in wafer starts per month.

Why it matters

Front-end capacity, technology and location decide which chips can be made, where and at what cost, so they dominate both industry strategy and policy debate. Process, equipment, facilities and yield engineers work in the front end, capacity planners and wafer buyers manage access to it, and investors and governments track fab investments closely.

In the chip lifecycle the front end sits between tapeout and assembly, and front-end process development runs years ahead of the products that use it.

Related terms

• Back-end
• Fab
• WSPM
• Upstream

Where it appears on the Hub

Used on 36 pages of the Hub. In each group, the pages that mention it most come first.