Surface Treatment Strategies for Sintered Power Modules
Dr. Stefan Thomaier, Adarsh Jyoti Das (Boschman)
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Investigation of Surface Treatment Strategies for Double-sided Cooled Sintered Power Modules: Impact on Mold Adhesion and Delamination Behavior
A cooperation of Boschman and ZESTRON
Brief Insight
Double-sided cooled sintered power modules enable high power density for next-generation GaN and SiC devices, but sinter-related residues and unfavorable surface properties can impair mold adhesion and promote delamination. Due to the narrow gap between the AMB layers, conventional plasma cleaning is challenging.
This study compares four ZESTRON wet chemical treatment methods with plasma-cleaned and untreated samples. Surface properties, contamination, and delamination behavior are evaluated using chemical and morphological analyses as well as C-SAM after PMC and thermal cycling. The results provide a basis for improved cleaning and surface preparation of sintered power modules.
Delivery form: PDF
Article number: EN-2605-04
Whitepaper
Investigation of Surface Treatment Strategies for Double-sided Cooled Sintered Power Modules: Impact on Mold Adhesion and Delamination Behavior
Abstract
A cooperation of Boschmann and ZESTRON
Double-sided cooled (DSC) power modules facilitate the high-power density of next-generation GaN and SiC devices; nevertheless, they also pose reliability problems when organic residues persist after sintering and molding or when disadvantageous surface properties (e.g. oxide layers) are not optimized. Contaminants from sinter paste and film can remain on substrate surfaces and in the sinter region, compromising adhesion between the substrate and molding compound, and aiding delamination during molding, post-mold cure (PMC), and thermal cycling. The restricted geometry and narrow gap between the top and bottom AMB layers make traditional plasma cleaning challenging, encouraging the exploration of other methods such as wet chemical surface treatment.
This study examines four wet chemical techniques by ZESTRON and compares them with traditional plasma-cleaned and non-treated samples to evaluate their effectiveness on sinter-related contamination and mold adhesion of finished module assemblies. Dummy and open samples are utilized to assess surface properties and correlate them with delamination behavior evaluated by scanning acoustic microscopy (C-SAM) at various process steps, including PMC and thermal cycling. Furthermore, chemical and morphological tests identify the organic species and sinter by-products that influence mold adhesion. The findings can act as a reference for enhanced cleaning and surface preparation techniques in both double-sided and single-sided cooled sintered power modules.
Key Topics
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Process Flow and Sample Building
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Surface Analysis Procedure
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Molding, PMC, and TMCL
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Surface Analysis – Before surface treatment
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Surface Analysis – After surface treatment
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Conclusion
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Dr. Stefan Thomaier
R&D Manager, Group Leader Analytics, ZESTRON Europe
Stefan Thomaier studied chemistry at the University of Regensburg and received his doctorate on the subject formulation of ionic liquid colloids for the synthesis of nanoparticles. Beside surface/interface-related topics and colloid chemistry, he is also experienced in the area of surface analysis. At ZESTRON Europe he is part of the R&D department, where he is responsible for the coordination of R&D projects and surface/interface analysis of electronic components.
Adarsh Jyoti Das (Boschman)
Adarsh Jyoti Das obtained his Mechanical Engineering degree from Rhine-Waal University in Germany and began his career at Boschman Advanced Packaging Technology as a Process Engineer. There, he worked with cross-functional teams to optimize and gain knowledge in back-end processes, including sintering, die attach, and molding, improving product performance and 0-hour reliability. Currently he works as a Package Development Engineer, where he collaborates closely with customers on power package development and supports tooling design for next-generation sintering and molding processes.
