Turnkey

Notes

Foundries increasingly offer turnkey advanced packaging, which puts them in direct competition with their OSAT partners.

Overview

Turnkey, in semiconductor manufacturing, describes an arrangement in which one supplier takes responsibility for a whole sequence of steps, typically the back end from wafer receipt through bumping, wafer probe, assembly, final test and shipment, so that the customer deals with a single point of accountability, schedule and price. Outsourced assembly and test companies (OSATs) commonly offer turnkey services, and some foundries offer turnkey packages that bundle wafers with partner back-end services. The opposite is a consigned or split flow, where the customer manages each supplier and moves material between them itself.

How it works

In a turnkey back-end flow the customer delivers processed wafers, or has the foundry ship them directly, together with the package design, test programmes and specifications. The supplier then bumps the wafers if needed, probes them at wafer sort, assembles good dice into packages, runs final test and any burn-in or system-level test, and packs and drop ships finished parts to the customer's warehouse or straight to its customers. Co-locating these steps in one site or one company shortens transit times between steps and keeps work-in-progress tracking in one system.

Commercially, turnkey pricing is often quoted per good unit shipped rather than per operation, which moves some yield risk to the supplier and makes cost easier for the customer to forecast. The supplier also takes on more of the logistics, inventory and quality reporting, and is held to agreed lead times and outgoing quality levels.

The term is also used more broadly. A turnkey ASIC or design service delivers a finished, tested chip from a customer's specification, with the provider handling design, tapeout, manufacturing and test. In each case the trade-off is the same: less management effort and one accountable partner, against less visibility and control over individual steps and more dependence on a single supplier.

Examples

• Amkor offering complete turnkey flip chip and wafer-level chip scale package flows at sites where bumping is co-located with wafer probe, assembly and final test.
• An OSAT whose turnkey service runs from package development and wafer probing through assembly, final test, reliability testing and drop shipment to the customer's customers.
• A start-up fabless company buying one turnkey price per good unit instead of managing separate probe, assembly and test vendors.
• A turnkey ASIC provider taking a customer's specification through design, tapeout and production test.

Related terms

• OSAT
• Final test
• Wafer bumping
• ASE Technology Holding
• COT
• Design services

Where it appears on the Hub

Used on 7 pages of the Hub. In each group, the pages that mention it most come first.