Microribbon Cable/Connector for Implantable Electronics

描述(申请人提供)：植入式微加工电极阵列，在短期内是非常有价值的研究工具，从长远来看，将对各种残疾患者的康复产生重大影响。在慢性系统中，互连通过经皮连接器形成微电极与外部世界之间的关键链接。密歇根大学已经将他们的探测器与微型、灵活的多引线硅带互连集成在一起。关键的问题是，由变薄的硅制成的丝带天生就很脆弱，而且在愈合过程中，由于组织收缩产生的机械应力，很容易断裂。为了克服这些限制，人们正在研究一种聚酰亚胺柔性电缆和一种离散连接器。聚酰亚胺电缆的初步测试表明，它不适合慢性植入物。拟议的工作重点将是用一种集成的刚性弯曲电路取代聚酰亚胺带状电缆和分立连接器，该电路由一种被称为液晶聚合物(LCP)的生物兼容材料制成，具有独特的性能组合。与聚酰亚胺相比，液晶聚合物几乎不吸湿，也不容易水解。带状电缆和连接器被制造为一体。与当前的混合方法相比，将连接器与柔性电缆集成是一项重大进步。这消除了一级互连，并导致与当前的分立式连接器相比，经皮连接器要小得多。最终，电缆将通过平面倒装芯片连接到神经探头，从而消除了线连接的需要。取消焊线将降低轮廓高度，消除一个主要的可靠性问题。

DESCRIPTION (provided by applicant): Implantable micro machined electrode arrays, in the short term, are highly valuable research tools, and in the long run will have great impact on rehabilitation of patients with various disabilities. In a chronic system, an interconnect forms the critical link between the microelectrode to the external world through a percutaneous connector. University of Michigan has integrated their probes with miniature; flexible, multilead silicon ribbon interconnects. The critical issue is that the ribbons are inherently fragile being made from thinned down silicon, and are prone to breakage as a result of the mechanical stresses created by tissue contraction during the healing process. To overcome these limitations, a polyimide flex cable and a discrete connector are being investigated. Preliminary testing of polyimide cables has indicated that it is unsuitable for chronic implants. The proposed effort will focus on replacing polyimide ribbon cables and discrete connectors with an integrated rigid flex circuit made out of a class of biocompatible materials known as liquid crystal polymers (LCP) with a unique combination of properties. Compared to polyimides, LCPs absorb virtually no moisture and are not susceptible to hydrolysis. The ribbon cable and the connector are fabricated as one piece. Integrating the connector with the flex cable represents a major advancement compared to current hybrid approach. This eliminates one level of interconnections, and results in a much smaller percutaneous connector compared to current discrete connectors. Ultimately, the cable will be bonded to the neural probe with a planar flip-chip bond, eliminating the need for wire bonds. Elimination of wire bonds will reduce the profile height and eliminate a major reliability concern.