This paper presents the results of a packaging process based on the stencil printing of isotropic conductive adhesives (ICAs) that form the interconnections of flip-chip bonded electronic packages. Ultra-fine pitch (sub-100-µm), low temperature (100 °C), and low cost flip-chip assembly is demonstrated. The article details recent advances in electroformed stencil manufacturing that use microengineering techniques to enable stencil fabrication at apertures sizes down to 20 µm and pitches as small as 30 µm. The current state of the art for stencil printing of ICAs and solder paste is limited between 150-µm and 200-µm pitch. The ICAs-based interconnects considered in this article have been stencil printed successfully down to 50-µm pitch with consistent printing demonstrated at 90-µm pitch size. The structural integrity or the stencil after framing and printing is also investigated through experimentation and computational modeling. The assembly of a flip-chip package based on copper column bumped die and ICA deposits stencil printed at sub-100- m pitch is described. Computational fluid dynamics modeling of the print performance provides an indicator on the optimum print parameters. Finally, an organic light emitting diode display chip is packaged using this assembly process. © 2007 IEEE.
|Number of pages
|IEEE Transactions on Components and Packaging Technologies
|Published - Mar 2007
- Computational fluid dynamics (CFD)
- Isotropic conductive adhesives (ICAs)
- Organic light emitting diode (OLED)