Some Scribbles.

Semiconductor Glossary

A running glossary of semiconductor terms.

Die

A block of semiconducting material on which a given functional circuit is fabricated, most commonly silicon. Hundreds or thousands of identical dies are patterned together onto a single wafer, then cut apart ("diced") into individual pieces.

Wafer

A thin slice of semiconductor material used as the substrate for fabricating integrated circuits.

Lithography

The process of transferring circuit patterns onto a wafer using light.

Doping

The intentional introduction of impurities into a semiconductor to modulate its electrical properties.

CoWoS

Chip-on-Wafer-on-Substrate — a 2.5D packaging process pioneered by [TSMC](https://semimarketcap.com/c/tsm). Logic dies and high-bandwidth memory (HBM) are mounted on a silicon **interposer**, a thin routing layer that connects them with dense, high-speed wiring. The assembled stack is then bonded to a substrate, producing the large multi-die packages used in AI accelerators and high-bandwidth networking chips.

CoWoS

HBM

High Bandwidth Memory — stacked DRAM built for much faster data transfer than conventional memory. Multiple memory dies are stacked vertically to pack more capacity into a smaller space, then placed beside the processor. HBM is standard in AI accelerators.

DRAM

Dynamic Random-Access Memory — computer memory that stores bits of data in tiny **memory cells**. The cells must be refreshed constantly or the data fades, which is why it's called "dynamic."