TIMtrace: Coverage Path Planning for Thermal Interface Materials

Thermal Interface Materials are used to transfer heat from a semiconductor to a heatsink. They are applied along a dispense path onto the semiconductor and spread over its entire surface once the heatsink is joined. To plan this application path, design engineers typically perform an iterative trial-and-error procedure of elaborate simulations and manual experiments. State-of-the-art path planning approaches are mainly focused on applications with a constant path width. They cannot be transferred to Thermal Interface Materials since the resulting area coverage depends on their complex flow behavior. We propose the fully automated optimization approach TIMtrace , which clearly outperforms the current manual path planning and respects all relevant manufacturing constraints. Generally, the design of an optimization problem highly influences its convergence properties. Our chosen path parameterization keeps the dimensionality of the independent variables reasonably low. We analyze different loss function components and respective weighting strategies with regard to both optimization convergence and result quality. TIMtrace enables an automated planning of dispense paths that do not contain voids, do not violate taboo zones and can be transferred easily to automated dispensing machines. An optimum dispense path helps to increase the reliability of the thermal interface and to make manufacturing more sustainable by reducing material waste. We show results on multiple real products from automotive series production, including experimental validation on actual series manufacturing equipment. • Novel approach for Coverage Path Planning problem. • Consistently outperform state-of-the-art approach for Thermal Interface Material. • Proposed method reduces: engineering efforts (by 80 %), material waste, cycle-time. • Results are validated on series manufacturing equipment using two actual products.