移动焦平面正反面曝光制备SU-8微结构及PDMS浓度梯度产生器

Fabrication of SU-8 microstructure and PDMS concentration gradient generator by moving focal plane front and back exposure

针对芯片实验室对浓度梯度产生器(CGG)的需求,为制作侧壁垂直的CGG,提出了一种移动焦平面正反面曝光制备SU-8光刻胶微结构的方法。该方法根据焦深将SU-8厚度分成多层,每曝光一次焦面向下移动一层,当曝光层数达到总层数一半时将样品翻转,同样采用移动焦面重复曝光的方式使SU-8内部形成光化学反应通道,得到充分曝光。最终利用SU-8微结构制作出聚二甲基硅氧烷(PDMS)CGG。测试结果表明:SU-8微结构实际轮廓侧壁垂直,没有出现“T”形结构,沟道高度为49.4μm;PDMS CGG侧壁垂直,沟道深度为49.3μm,满足CGG侧壁垂直要求。

According to the requirement for the concentration gradient generator(CGG)in the chip laboratory,a method of moving focal plane front and back exposure to fabricate SU-8 photoresist microstructure is developed for fabricating CGG with vertical sidewalls.In the method,the thickness of SU-8 photoresist is divided into multiple layers according to the focal depth,and the focal plane moves one layer down with each exposure.When the number of exposed layers reaches half of the total layers,the sample is turned over,and the same exposure way is repeated.At last,the photochemical reaction channel inside SU-8 is formed,and SU-8 is fully exposed.Finally,polydimethylsiloxane(PDMS)CGG is fabricated using the SU-8 microstructure.The results show that the sidewall of the SU-8 microstructure is vertical,without"T"shaped structure,and the channel height of the SU-8 microstructure is 49.4μm.The sidewall of PDMS CGG is also vertical with the channel depth of 49.3μm,fully meeting the vertical requirements of CGG sidewalls.