超声波键合熔接结构及压力自平衡夹具

聚合物微流控芯片对键合精度、键合强度及键合效率要求高。为了避免超声波键合中微通道被堵塞,解决键合过程中由调平精度和高频振动引起的键合强度低、键合压力分布不均的问题,设计了一种基于超声波键合的熔接结构和压力自平衡夹具。首先,利用感压胶片对压力自平衡夹具和不带自平衡功能的夹具的压力分布进行测量,并定义了压力分布系数进行量化。其次,利用两种夹具分别对设计芯片进行超声键合,并利用工具显微镜对焊线和微通道截面进行观测。最后,对两组芯片进行键合强度测试和密封性测试。实验结果表明:所设计的熔接接头结构对微通道的控制精度可达2.0μm。压力自平衡夹具结构简单可靠,可提高压力均匀性35.20%~43.18%,并使得焊线均匀一致,同时可提高键合强度15.3%~45.1%,并保证密封性。该熔接结构和压力自平衡夹具可满足聚合物微流控芯片的控制精度、键合强度、压力均匀性及其密封性的要求。

A joint structure and self-balancing jig based on ultrasonic bonding

Polymer microfluidic chips have high requirements for bonding precision, bonding strength and bonding efficiency. In order to avoid the clogging of microchannel by fusion and solve the problems of low bonding strength, uneven pressure distribution caused by leveling precision and high-frequency vibration in the process of ultrasonic bonding, the joint structure and self-balancing jig were designed and fabricated. First, based on the self-balancing jig and conventional jig with no leveling function, the pressure distribution coefficient was defined and measured by prescale film. Moreover, the chips we designed were bonded with two types of jigs respectively. The bonding line and cross-section of microchannels were measured by measuring microscope. Last, these chips were tested by electric tensile tester and sealing test. Experimental results indicate that the precision of controlling microchannel can reach about 2.0 μm. The self-balancing jig can improve pressure distribution about 35.20%-43.18% with simple structure and easy operation, and make the bonding line uniform. The bonding strength increases about 15.3%-45.1% with excellent sealing performance. It concludes that the joint structure and self-balancing jig can satisfy the requirements of controlling precision, bonding strength, pressure distribution and sealing performance.