Rapid fabricating process of flexible PDMS- film with array micro round holes by blowing organic net framework

Abstract

Flexible organic films with through-holes array count for many fields, such as flexible MEMS structures and electrochemical machining (ECM) masks. Polydimethylsiloxane (PDMS) is a material often used as flexible films due to the advantages of chemically inert, transparent, and well-combined with silicon-based materials. Generally, the flexible films with through-holes were fabricated by the pattering dies based on MEMS processes. However, the die area is very limited by the wafer size in the photolithography process although the holes can be accurate. A PDMS gas-blowing process is capable of fabricating flexible films with arrayed micro holes in a rapid and low-cost way, but the process is lacking theoretical foundations and parametric rules. It is hard to realize a controllable, repeatable and stable fabricating process. In this research, we established physical models to analyze the effect of key parameters and constraint conditions on the PDMS gas-blowing process. Experiments were carried out to achieve the parametric rules, providing a reference to optimization. To avoid the problem of over-blowing during the repeated blowing process, we further proposed an online optics detection method to identify the closed meshes and make the targeted blowing process. This can effectively improve the round-holes forming ratio in this method. As a result, the array micro round holes of 75–235 μm through the flexible PDMS-films can be fabricated rapidly.