LASER-BOND

Semiconductor devices are becoming smaller, more powerful and more complex every year. Keeping up means manufacturers need to find smarter and greener ways to produce them.

Within embedded die packaging, surface preparation is a critical part of the manufacturing process. Before materials are ready for bonding, lamination and the subsequent stages of manufacture, copper surfaces must be carefully prepared. Traditionally, this relies on a series of wet chemical treatments to remove contamination and oxide layers, modify copper surfaces and prepare materials for downstream processing. While effective, these processes add complexity through additional process steps, hazardous chemical handling, dedicated processing equipment and waste treatment, increasing both operational costs and factory footprint.

The LASER-BOND project set out to investigate whether selected wet chemical surface preparation stages could instead be completed using a laser-based alternative. This feasibility study was tested using Watt Laser’s turnkey, digitally controlled laser ablation platform (MLAb).

Combining Watt Laser’s expertise in precision laser processing and RAM Innovations’ knowledge of embedded die packaging and downstream process validation, RAM Innovations established a structured programme of experiments covering oxide removal, micro-etching, adhesion promotion, copper interaction, surface preparation before soldering and passivation removal.

Watt Laser processed representative test panels, using carefully controlled laser parameters before they were evaluated by RAM Innovations through a series of downstream manufacturing tests. The objective was not only to determine whether laser processing visibly altered the surface, but also whether the laser-treated materials continued to perform successfully during the manufacturing processes that followed. Evaluation methods included water break testing, microscopy, dry film lamination, die attachment and adhesion assessment.

The project successfully demonstrated the technical feasibility of laser-based oxide removal, surface cleaning and micro-etching as alternatives to conventional wet chemical surface preparation. Laser-treated copper surfaces became fully hydrophilic, confirming effective removal of surface oxides and contamination while supporting successful die attachment using conductive adhesive. Dry film also adhered successfully to laser-treated areas, providing further evidence that the laser process created a functional surface suitable for downstream manufacturing without conventional chemical preparation.

Although adhesion promotion and passivation removal required further optimisation, these investigations identified the remaining technical challenges while confirming the feasibility of several laser-based surface preparation processes.

Ultimately, the LASER-BOND project demonstrated that precision laser processing could feasibly replace selected wet chemical preparation stages within an embedded die packaging workflow. The findings provide a strong foundation for future industrial development, with the potential to reduce chemical dependency, simplify production workflows and consolidate multiple manufacturing stages into a single laser-based process.