Papers by Keyword: Undercut Ratio

Abstract: The NAK80 die steel was processed in spray etching with mask preprocessing.The effect of the mask gap width and etching depth on the undercut ratio was investigated . The result shows that with the increase of the mask gap width the effect of the etching depth on the undercut ratio increases. Based on the experiment, the relation of the mask gap width, the etching depth and the undercut ratio is obtained.

Abstract: This paper presents a simple but reliable fabrication process for microfluidic devices on glass substrate using wet etching technology. Instead of using expensive Pyrex glasses as substrates and depositing expensive metal or polysilicon/amorphous silicon as etch masks in conventional method, glass slide is used as substrate and a single-layer negative photoresist RFJ-220 is used as the etching mask. The etch rates, generation of defects, undercut ratio and surface roughness are studied. In order to achieve high etching depth and smooth surface, buffered oxide etching with hydrochloric acid as additive is proposed. By proper cleaning and long-time hard baking, the undercut ratio can approach to 1. An 110μm depth microchannel with smooth surface is achieved. This fabrication process leads to a considerable reduction of process steps, fabrication time and material consumption. With this technique, we successfully fabricated a microfluidic device, which is used in the capture of hepatoma cells HepG2.