Perfusable multi-scale channels fabricated by integration of nanoimprint lighography (NIL) and UV lithography (UVL)

• Published in: Microelectronic engineering Vol. 98; pp. 58 - 63
• Main Authors: Isobe, Gaku, Kanno, Isaku, Kotera, Hidetoshi, Yokokawa, Ryuji
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.2012; Elsevier
• Subjects: Applied fluid mechanics; Applied sciences; Arrays; Channels; Cross-disciplinary physics: materials science; rheology; Devices; Electronics; Exact sciences and technology; Fluid dynamics; Fluidics; Fundamental areas of phenomenology (including applications); Lithography; Materials science; Methods of nanofabrication; Microelectronic fabrication (materials and surfaces technology); Microfluidics; Micrometers; Molds; Nanoimprint lighography (NIL); Nanolithography; Nanoscale pattern formation; Nanostructure; Perfusion; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; UV lithography (UVL); Nanoimprint lighography (NIL); UV lithography (UVL); Perfusion; Microfluidics; Dimethylsiloxane polymer; Fluid mechanics; High resolution; Submicrometer; Epoxy resin; Micromachine; Nanolithography; Array; Microelectronic fabrication; Light sensitive polymer; UV lithography; Multiscale method; Pressure drop; Silicon; Miniaturization; Compatibility; Photolithography; Interface
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2012.05.059

[Display omitted] ► UV assisted NIL and UVL are integrated for submicrometer microfluidic channel array. ► The channel array was transferred to PDMS for disposable bioassay device. ► Perfusion of two solutions was demonstrated in the channel array. Numerous microfluidic devices have been applied to bioassays. Decreasing amount of liquid solutions helps to reduce sample waste and reagent consumption. Increasing sensitivity with fast reactions is another advantage. However, further downsizing of microfluidic devices brings difficulties in perfusing solutions due to a pressure drop, which is essential in bioassays. Here, we report a perfusable channel array in submicrometer to micrometer scale fabricated by integrating nanoimprint lithography (NIL) and UV lithography (UVL). Two lithography techniques are used to fabricate multiscale SU-8 mother mold for poly(dimethylsiloxane) (PDMS) replicas. SU-8 is an appropriate material as a mold due to mechanical stability and chemical resistance. However, it causes problems in a NIL process such as SU-8 residue on a silicon mold after demolding from a patterned SU-8 surface. To keep the compatibility of SU-8 in NIL process, UV-assisted NIL is employed to fabricate the line-and-space pattern for the channel array and microscale structures for microchannels were defined by UVL. NIL provides high throughput and high resolution patterns for the channel array, while UVL defines micrometer scale channels as interface between a user and the channel array. The fabricated device consists of a channel array (w=0.5–2μm, h=1–2μm, l=200μm) and 2μm scale channels (w=250μm, h=50μm, l=5mm). These micrometer scale channels are used for inlet or outlet of the channel array to deliver solutions. We demonstrated exchanging solutions using fluorescent solutions. Repetitive increase and decrease of fluorescent intensity proved the solution exchange in channel array.