tapeouts

Tapeout is the milestone in integrated circuit design at which the physical layout is finalized and prepared for fabrication. Historically, designs were literally taped onto magnetic tape to ship to a foundry for mask creation; the term persists even though today data is transferred electronically. A successful tapeout indicates the layout meets design rules and is ready to be manufactured.

The tapeout package typically includes the GDSII or OASIS layout data, LEF/DEF for timing and placement information, a complete mask set description, and verification results. Before tapeout, designers perform extensive physical verification, including design-rule checks (DRC), layout-versus-schematic checks (LVS), and signoff for timing, power, and manufacturing constraints. The mask data are used to produce photomasks for each layer; in some processes, additional reticles implement critical layers.

Scope and process: A tapeout may cover a full chip or IP blocks, and may involve multi-project wafers to share mask costs. After submission, changes are expensive and can delay production, so last-minute alterations are minimized. Mask data are validated and submitted to the foundry; the format is typically GDSII or OASIS, with process-specific requirements affecting the timeline.

Impact: Tapeout represents a major production milestone. After tapeout, the risk of late changes increases, and fabrication yields, test, and silicon verification drive the ultimate success of the design. Post-tapeout steps include mask fabrication, wafer manufacturing, die testing, and debugging, with potential re-spins if silicon performance does not meet expectations.