New bonding technology for microelectronics

The cost of packaging in microelectronics accounts for 30 % of total production costs. However, this is rising at an alarming rate because of increasing consumer demand for smaller and smarter portable electronic devices. Technological advances to reduce packaging costs are therefore of crucial importance to maintain the competitive edge of EU packaging and assembly companies.

Microelectronics packaging often makes use of thermosetting polymer materials such as encapsulants, underfills or electrically conductive adhesives. Initially, thermosetting polymers are liquid or paste-like and are hardened through a curing process. An alternative approach to conventional heating methods is the use of microwave energy that results in substantially shorter curing times.

In the EU-funded project 'Frequency agile microwave bonding system' (FAMOBS), researchers developed a novel tool that uses pulsed microwave radiation and selects a few cavity frequencies to improve the bonding quality. Possible applications include curing underfill materials, bonding components to a printed circuit board or even reworking defective components.

This tool is an open-cavity bonding system that allows point selective heating. As such, it can be integrated into a precision placement machine to allow processing single components in a whole printed circuit board. Furthermore, the open design enables simultaneous placement, alignment and curing. Reel-to-reel processing is another application of this technology.

Compared to a convection oven, the material is heated from the inside, which results in shorter curing times. It is thus possible to cure certain materials 10 times faster. The system has a process accuracy of less than 10 micrometres.

With the exodus of a high volume of packaging and assembly companies to low-wage countries, it becomes clear that the European manufacturing industry needs to revitalise itself. Due to the significantly shorter cycle times, this newly developed technology is expected to provide European packaging companies a clear competitive advantage. It should also allow them to produce assembly equipment and materials that will feed into the Asian market.