Novel High Density Interconnects for Flexible Neural Prostheses

描述（由申请人提供）：为了使先进的神经刺激器植入装置（如人造视网膜）成为现实，需要具有用于刺激的集成微电极阵列和集成微电子器件的高度灵活的微型化装置。目前的原型装置仍然太笨重，并且在包装和互连方面存在许多缺点，无法在体内长期存活。特别是对于具有新的柔性聚合物基底的植入式神经假体，未解决的关键问题之一是硅芯片与基底和电极阵列的封装、集成和连接。对电极数量增加、小型化和新材料使用的需求要求开发用于这些微尺寸神经植入物的新包装方法。我们建议开发一种新的芯片到柔性基板组装技术，这将大大减少刺激器植入设备的尺寸，并提高柔性基板和电子芯片之间的连接。在我们的方法中，我们将联合收割机的优势与我们的研究机构合作伙伴RTI International正在开发的3D集成或“芯片堆叠”的优势相结合，直接将旋涂聚酰亚胺加工到晶圆的整个表面区域。聚酰亚胺基板通过焊料凸点或填充层化学键合到晶片上，而芯片和柔性基板没有分离，这些都是慢性植入物的弱点。通过我们专有的A-coat阻隔膜进行沉积和封装，增强了保护。半导体晶片互连允许3-D堆叠和到有源IC器件的高密度连接。通过堆叠和垂直集成薄裸硅芯片和无源元件，我们可以保持或提高当前的处理能力，同时保持或降低现有器件的当前尺寸和重量。电容器等无源元件可以集成到电路中并从基板上移开。使用传统的聚酰亚胺加工技术，薄芯片封装将更容易密封。

DESCRIPTION (provided by applicant): To make advanced neural stimulator implant devices such as the artifical retina a reality highly flexible minituarized devices with integrated microelectrode arrays for stimulation and integrated microelectronics are needed. Current prototype devices are still too bulky and have many shortcomings in packaging and interconnects to survive long-term in-vivo. 1 of the unresolved critical issues particularly for implanted neural prostheses with new flexible polymeric substrates is packaging, integration and connection of silicon chips with substrate and electrode arrays. The requirements for increased numbers of electrodes, increased miniaturization and use of new materials demands the development of new packaging methods for these micro size neural implants. We propose to develop a novel chip-to-flex substrate assembly technique which will reduce the size of the stimulator implant device substantially and improve the connectivity between flex substrate and electronic chip. In our approach, we combine the advantages of direct processing of spin-on polyimides onto the whole surface areas of the wafer with the advantages of 3D integration or "Chip Stacking", which is being developed by our research institution partner RTI International. The polyimide substrate is chemically bonded to the wafer with no separation of chip and flex substrate through solder bumps or filler layers, all weak points in chronic implants. Protection is enhanced through deposition and encapsulation with our proprietary A-coat barrier films. Through-wafer interconnects allow 3-D stacking and high density connections to active 1C devices. By stacking and vertically integrating thin bare Si dies and passive components, we can maintain or increase current processing power while maintaining or decreasing current size and weight of existing devices. Passive components like capacitors can be integrated into the circuitry and moved off the substrate. The thin chip package will be easier to seal using traditional polyimide processing techniques.