Laser micromachining as a metallization tool for microfluidic polymer stacks

Abstract

A novel assembly approach for the integration of metal structures into polymeric microfluidic systems is described. The presented production process is completely based on a single solid-state laser source, which is used to incorporate metal foils into a polymeric multi-layer stack by laser bonding and ablation processes. Chemical reagents or glues are not required. The polymer stack contains a flexible membrane which can be used for realizing microfluidic valves and pumps. The metal-to-polymer bond was investigated for different metal foils and plasma treatments, yielding a maximum peel strength of R ps = 1.33 N mm −1 . A minimum structure size of 10 μm was determined by 3D microscopy of the laser cut line. As an example application, two different metal foils were used in combination to micromachine a standardized type-T thermocouple on a polymer substrate. An additional laser process was developed which allows metal-to-metal welding in close vicinity to the polymer substrate. With this process step, the reliability of the electrical contact could be increased to survive at least 400 PCR temperature cycles at very low contact resistances.

Processamento de superfícies poliméricas com pulsos laser de nano e femtossegundos

“…Materiais poliméricos, por apresentarem maior acessibilidade e manufatura que materiais cerâmicos [18,26], têm despertado muita atenção de pesquisadores das mais diversas áreas [27][28][29][30]. Para demonstrar as capacidades da microfabricação com pulsos laser de fs, recentemente foi demonstrada a produção de microcanais em poliamida e polimetacrilato de metila (PPMA), visando aplicações em microfluídica [31].…”