Session 18: FHE Chip Integration

Investigation of Ultrathin/High IO Die Attach to Flexible Substrates
Thursday, February 15, 2018
10:15 AM - 10:40 AM

A cost-effective way to manufacture high volume assemblies of ultrathin, high I/O bare die chips onto screen printed circuitry for wearable applications was investigated. This is a NextFlex Initiative with collaborations among Cal Poly, Jabil, Dupont, and Novacentrix. Thermoplastic polyurethane (TPU) was selected as it is commonly used as a substrate in wearable applications on which conductive ink is printed. TPU has a low melting point and high coefficients of thermal expansion and elasticity, thus creating challenges for more traditional methods of die attachment (e.g. soldering). Two methodologies—anisotropic conductive film (ACF) and anisotropic conductive adhesive (ACA)—were investigated to attach a large (10mm x 10mm) ultrathin bare die with over 400 bumps to a TPU substrate with printed circuitry. This presentation explores the methodology of the research for the two technologies (ACF and ACA), and presents results of the experiments, as well as suggestions for further research and investigation. This material is based upon work supported, in part, by Air Force Research Laboratory under agreement number FA8650-15-2-5401. The U.S. Government is authorized to reproduce and distribute reprints for Governmental purposes notwithstanding any copyright notation thereon. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of Air Force Research Laboratory or the U.S. Government.