A semiconductor fab is a facility that builds integrated circuits or discrete devices on wafers through hundreds of tightly controlled process steps. The term fab is short for fabrication plant. It is different from assembly and test facilities, which package and verify the finished dies after wafer processing.
What happens inside a fab
Fabs repeatedly add, pattern, modify and remove thin material layers on a wafer. Each operation must align with earlier layers while controlling particles, chemistry, temperature and process variation. The finished wafer contains many copies of the designed device before it is cut into individual dies.
Start with prepared wafers
Most integrated circuits begin on high-purity silicon wafers, although silicon carbide, gallium nitride and other materials are used for specialized power, RF and optoelectronic devices. Incoming wafers are inspected for thickness, flatness, crystal quality and surface condition.
Deposit and grow material layers
Oxidation and deposition processes form insulating, conducting and semiconductor films. Common methods include chemical vapor deposition, physical vapor deposition and atomic layer deposition. Film thickness, composition, uniformity and stress must stay within the process window.
Pattern each layer with lithography
Lithography transfers a circuit pattern from a mask or reticle to photoresist on the wafer. Exposure, focus, alignment, resist coating and development all affect the printed geometry. Advanced processes may use multiple patterning steps to create features smaller than a single exposure can resolve.
Etch, implant and modify the wafer
Wet or dry etching removes selected material after patterning. Ion implantation introduces dopants that change electrical behavior, followed by thermal processing to activate and repair the crystal. Cleaning steps between processes remove residues without damaging critical surfaces.
Build interconnect layers
After transistor or device structures are formed, metal and dielectric layers connect them into circuits. Contact resistance, line width, via fill and dielectric integrity affect performance and yield. Chemical-mechanical polishing keeps the wafer surface flat enough for later layers.
Use cleanrooms and contamination control
Small particles, trace metals and airborne molecular contamination can damage features or change device behavior. Fabs use filtered environments, controlled airflow, specialized garments, chemical monitoring and strict material handling. The required controls depend on process sensitivity and feature size.
Measure every critical process
Metrology tools measure thickness, dimensions, overlay, defects and material properties throughout production. Statistical process control detects drift before it creates widespread yield loss. Electrical test structures on the wafer provide additional data about device and interconnect performance.
Understand fab, foundry and fabless models
An integrated device manufacturer designs and fabricates its own products. A foundry manufactures designs for other companies. A fabless company focuses on chip design and uses an external foundry for wafer fabrication. Assembly, packaging and final test may be performed by the manufacturer or an outsourced semiconductor assembly and test provider.
Why equipment and supply chains matter
A fab depends on lithography, deposition, etch, implant, cleaning, metrology and automation equipment plus ultrapure chemicals, gases, wafers, masks and spare parts. Qualification and change control make sudden substitutions difficult. Capacity planning therefore depends on both tool availability and a stable qualified supply network.
Industrial automation providers also support fab operations; the Siemens semiconductor industry overview is one example of the digital production systems used across this sector.
From wafer completion to finished components
After wafer fabrication, electrical wafer sort identifies passing dies. The wafer is diced, and selected dies are attached, interconnected and encapsulated or integrated into advanced packages. Final test, marking and packing prepare the components for shipment and board assembly.
Key terms to distinguish
- Fab: facility that processes wafers
- Foundry: fab business that manufactures customer designs
- Fabless: chip company without its own wafer fab
- OSAT: outsourced semiconductor assembly and test provider
- Process node: a generation label that relates to a manufacturing technology
- Yield: the share of devices meeting acceptance criteria
For component sourcing after fabrication and packaging, review our active component capabilities or contact Informic with your part list.
