As the demand for flexible hybrid electronics has increased extensively e.g. for the internet of things (IoT), electronic skin and wearables applications, the implementation of devices based on low-cost materials such as PET, paper, and unpackaged bare dies have become crucial for economical mass production. To facilitate flexibility for instance in wearables, the rigid silicon-based components are also deemed to become ultra-thin, which raises major challenges in terms of handling and reliable integration. In this paper, the hybrid integration of ultra-thin dies on PET and paper-based printed substrates is investigated. Silicon dies with different thicknesses from 10 to 50 μm with an internal daisy-chain structure were made and flip-chip bonded to screen-printed substrates. The bonding was conducted by using two types of anisotropic conductive adhesives, i.e. anisotropic conductive films (ACF) and anisotropic conductive paste (ACP). The effect of die encapsulation on the reliability of the assembly was also assessed by employing a protective foil. For reliability analysis, a cyclic bending test was carried out to identify the failure cycle. The successful integration of ultra-thin chip on the low-cost printed flexible substrate was obtained by optimizing the bonding parameters with both ACF and ACP. It was revealed that in flexible hybrid electronics; the thinner the die, the higher is the reliability, as the thinner dies promise superior flexibility, and can withstand higher bending stresses. Moreover, it was found that encapsulation of the thin die in a foil dramatically increases the long-term reliability of the bonded chip.

随着对柔性混合电子产品的需求广泛增加，例如物联网 (IoT)、电子皮肤和可穿戴设备应用，基于低成本材料（如 PET、纸张和未封装裸片）的设备的实施对于经济批量生产。为了促进可穿戴设备的灵活性，刚性硅基组件也被认为是超薄的，这在处理和可靠集成方面提出了重大挑战。在本文中，研究了超薄模具在 PET 和纸基印刷基板上的混合集成。制造了具有内部菊花链结构的 10 至 50 μm 不同厚度的硅芯片，并将其倒装芯片粘合到丝网印刷基板上。通过使用两种类型的各向异性导电粘合剂，即各向异性导电膜（ACF）和各向异性导电膏（ACP）进行粘合。还通过使用保护箔来评估芯片封装对组件可靠性的影响。对于可靠性分析，进行了循环弯曲试验以确定失效周期。通过优化 ACF 和 ACP 的键合参数，实现了超薄芯片在低成本印刷柔性基板上的成功集成。据透露，在柔性混合电子产品中；芯片越薄，可靠性越高，因为芯片越薄，柔韧性越好，并且可以承受更高的弯曲应力。而且，