Quantum foundry qualification: what buyers should verify

A quantum foundry is ready for your programme when it can reproduce the process your design requires, provide the necessary access and deliver devices that pass agreed tests after packaging. Wafer diameter, public funding and a prominent partner are useful context, but do not establish yield, production allocation or compatibility with your system.

Device requirements and process design kits

A fabrication decision begins with the device and its interfaces. A superconducting circuit, a silicon spin device and an integrated photonic chip need different materials, process steps and measurements. Specify the required electrical or optical behaviour, operating temperature, package and connection to the control system. Distinguish the first experimental lot from a production release. Access that is sufficient for design exploration may be unsuitable for a delivery programme with fixed acceptance dates and repeat orders.

A process design kit, or PDK, supplies the rules and models used to translate a design into a manufacturable layout. Ask which version is qualified, which components have measured data and which remain experimental. Establish whether the models describe performance at the intended operating conditions. A design-rule check can show that a layout respects geometric constraints while leaving quantum performance unresolved. Changes to the PDK should have a documented effect on existing designs, including whether another fabrication run or package design is required.

Yield and packaging evidence

Industrial tools provide an opportunity for repeatability, not evidence that every resulting device is usable. The 2024 demonstration of superconducting qubits manufactured on 300 mm wafers illustrates a concrete research result on an industrial process platform. It cannot establish the commercial yield or available capacity of every quantum foundry. For a proposed supplier, request distributions across relevant lots rather than the best measured die. The denominator should include tested failures and exclusions, with the process revision and measurement conditions attached.

Yield needs several definitions. Fabrication yield describes devices surviving a process or inspection, whereas functional yield depends on meeting the performance required by the customer. Packaging and integration may reject further units. In an explicitly illustrative order of 100 dies, 80 could pass wafer tests and only 60 satisfy the final packaged-device specification. The useful yield for that purchase is then 60%, not 80%. Prices quoted per wafer, delivered die and accepted package cannot be compared before those boundaries are reconciled.

Packaging must be part of the qualification, because the buyer ultimately uses a connected device. Assign responsibility for die handling, bonding, optical coupling, thermal interfaces and final characterisation as applicable. Decide who investigates a device that passes at the foundry but fails after assembly. A complete fabrication record should permit the parties to isolate a process issue from a packaging or system problem. Otherwise each organisation can meet a narrow specification while the buyer receives no accepted product.

Manufacturing access and continuity

Access is a separate commercial question. The European Commission’s Quantum Europe Strategy recognises production and design infrastructure as an industrial priority. A place in that ecosystem does not establish a reserved manufacturing slot. Ask what capacity is allocated to your programme, how cancellations work, who has priority during disruption and whether process development consumes the same tools as repeat production. Planned expansion should enter the schedule only at the appropriate commissioning and qualification stage.

The agreement should connect process ownership to continuity. Establish rights to design files, customer-specific improvements, measurement records and a replacement manufacturing route. A second source can reduce dependence only after the design has been transferred and tested there; a nominally similar process is insufficient. Determine the cost and elapsed time of that transfer before relying on it as a contingency. Confidential know-how and specialised equipment can make practical portability narrower than the contractual right to move a design.

A proportionate commitment therefore has successive acceptance points: a defined process, a representative lot, an accepted package and repeated delivery within the required window. Payments can follow evidence without forcing either party to promise a mature volume that does not yet exist. For an investor, the same sequence separates announced capacity from economically useful output. A foundry relationship becomes industrially valuable when it lowers uncertainty in the customer’s delivered product, rather than simply increasing the number of fabrication resources named in a roadmap.