Design of a novel thermocompression bonding module
For high throughput Flex-on-Substrate assembly
M.A.C.C. van den Hurk (TU Delft - Mechanical Engineering)
Jo W. Spronck – Mentor (TU Delft - Mechatronic Systems Design)
Sander Dorrestein – Mentor (TEGEMA Eindhoven BV)
Matthijs Langelaar – Graduation committee member (TU Delft - Computational Design and Mechanics)
Joep P.A. Nijssen – Graduation committee member (TU Delft - Mechatronic Systems Design)
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Abstract
Flex-on-substrate assembly is an increasingly popular electronics assembly type that is based on thermocompression bonding: a combination of high temperature and pressure. Currently, up to two-thirds of the cycle time is spent on heating and cooling. To meet the growing demand for flex-on-substrate production in the future, the heating and cooling steps must be more time-efficient. In this thesis, a bonding module is designed that is heated and cooled by using a 150W halogen lamp as a heating source and a staggered-tube heat exchanger with forced airflow as a cooling system. The design requires understanding of the bonding process and models containing the governing physics. Therefore, finite element models were made for both heating and cooling which were validated by manufacturing a demonstrator and applying a typical thermocompression bonding temperature profile to the heating element. From the experiment it follows that the concept shows potential for further product development but does not yet perform as required. The reflector surface reflectance,which has an important impact on the energy efficiency, was too low in this demonstrator. Furthermore heat leaks away from the heating element which inhibits a fast temperature rise and the complex cooling system geometry leads to manufacturing errors, which cause leaks in the cooling channel. By improving the design on these points, this concept can decrease the current cycle time by more than 50% and keep up with the growing demand for flex-on-substrate assemblies.