A working prototype often decides the next funding round, the first customer or the market window. For many teams developing PICs, quantum chips, RF modules or biosensors, the device design is ready long before the die attach process is. How that gap is closed decides how fast the prototype comes, and whether it scales into production.
Does this sound familiar?
Questions many R&D teams are asking:
- We have a new device and no assembly process yet. Who can develop the die attach for us?
- We need working prototypes for our next funding round. Who can assemble our chips without us buying equipment?
- How can we test whether our chips and materials can be bonded before we invest in a die bonder?
- Our die attach works on a few samples. How do we make sure it works in production?
Whether the device is built from electronic dies, photonic integrated circuits (PICs), laser diodes or quantum chips, the situation behind these questions is often the same. A milestone is fixed, die bonding is not the team’s core business, and there is no time for a wrong turn.
Get the die attach right from the start
In photonic modules, assembly and packaging often dominate the manufacturing cost (1). For co-packaged optics, Yole Group expects packaging to capture roughly half of the market value around 2026 to 2027. (2) And much of the packaging cost is set in development, long before the first production run.
Pad and bump layout for flip chip bonding, interconnect metallurgy, fiducials, die thickness, tolerances: many design choices depend on how the dies will be bonded. Settling them with the process in view avoids a costly re-spin later.
Electronics and photonics are merging through advanced packaging and heterogeneous integration, with co-packaged optics as the clearest example. In photonics packaging, optical interfaces often need sub-micron alignment to waveguides, fibers or other dies, and the coupling has to survive the heat and force of bonding.
Then comes the choice of technology: thermocompression, laser-assisted, cold compression, ultrasonic, eutectic, soldering, adhesive or hybrid bonding. Many devices need a combination.
The right choice depends on:
- The materials and how much heat and force they tolerate
- Where the device will operate, from implants inside the human body to cryogenic temperatures in quantum packaging
- The accuracy and interconnect density the design needs
- Cycle time and cost per bond in production
A process that works for ten prototypes may lack the repeatability, yield and reliability that volume production demands, or be too slow and too expensive per bond. Choosing with production in mind saves a second development round.
Where the pressure comes from
Teams in this situation are usually under pressure from several sides at once.
Time. The milestone was set by a funding body, an investor or a customer. If the team buys a die bonder first, selecting, ordering, installing and learning it all happen before the first real bond. Every week spent there is missing at the end, and time to market slips.
Budget. A die bonder is a capital investment. Development work is often easier to fund than equipment, and investors want to see a working device before they pay for a production line.
Knowledge. R&D teams know their device inside out. Die attach is a discipline of its own, and building that know-how by hiring or by trial and error takes longer than most project plans allow.
Risk. Equipment bought too early may come with the wrong technology or configuration. A design frozen too early may force a re-spin once assembly starts. A process that only works in the lab has to be developed again at transfer.
Develop, outsource or both
For the die attach process, there are basically three options.
Develop in-house. The team buys die bonding equipment, hires or trains people and develops the assembly process itself. It keeps full control and builds lasting packaging know-how. It also carries the full capital cost and the full learning curve before the first functional sample exists.
Outsource the development. A specialist develops the die attach process on its own equipment, with the customer’s dies. The prototype comes faster and without capital spending. The risk is dependency: if the process lives only in the partner’s lab, the team ends up with samples and without the capability to build more.
Combine both. The die attach process is developed externally until the technology is validated, then brought in-house on equipment specified by the results.
For teams racing to a first prototype, combining both is usually the most sensible route. It keeps the schedule, defers the capital decision until there is data, and ends with a process the team owns.
What to ask before handing over the dies
When working with an external partner, a few questions show quickly whether the result will hold beyond the first samples.
Is the process documented, or are only parts delivered? A useful result documents what was tested, which parameters worked and where design changes would help. That feedback is most valuable while layout and interconnect choices can still change. Ideally, the process files are included, so the recipe can run on the team’s own system later.
Does the partner build tooling for the specific dies? Bond tools, nozzles and fixtures define how a die is picked, held and bonded. A trial with generic tooling says more about the tooling than about the process.
Is the development platform the same as the production platform? If it is, recipes move from R&D to production directly. If not, a second development round at transfer is likely.
Is the scope flexible? A new material combination can run smoothly or need several iterations. A fixed scope set before the first trial either wastes budget or stops too early.
Process development at Finetech
Finetech’s application team develops repeatable die attach processes on your dies, with almost 35 years of die bonding experience. A short demo on your samples shows whether your approach can work. Projects are scoped around your deliverable, with custom tooling designed and built where needed, and development time is usually billed by the day.
You receive functional samples, a report with documented process results, design feedback and an equipment recommendation, plus the optimized process files. If you choose a Finetech system, development continues while it is being built, and your first run starts from a proven recipe.
TERASi took this route. The deeptech start-up from Stockholm builds RF components and complete wireless modules for 5G and future 6G systems. Sample trials at Finetech proved feasibility and became TERASi’s first practical implementation of its concepts. The system was then configured around the process, with custom tooling and modules added as the application required. Today, TERASi builds complete SiP modules on its own Finetech die bonder.
Racing to your first prototype? Send us a message and tell us what you need to bond.
