Design and Fabrication of a Multi-Probe Device with Microfluidics for Massively Parallel NanolithographyKeun-Ho Kim , Ph.D., Northwestern University, 2006.
Major Professor: Dr. Horacio D. Espinosa.
The capability of highly localized patterning of biomolecules and nanoparticles on surfaces permits nanofabrication of functionalized structures that serve as templates to guide the assembly of biological and nanosensors. This dissertation presents the consideration on the development of nanopatterning and surface engineering methods in a scanning probe-based approach.
Originated from atomic force microscope (AFM) cantilevers, a new microfluidic probe, named nanofountain probe (NFP), that is capable of sub-100 nm resolution of molecular writing and continuous sample feeding is presented. Design issues are discussed to implement the requirements for the probe. Microfabrication sequences are established to build NFP chips that integrate microfluidic components permitting continuous feeding and high-resolution writing. Experimental examinations of the NFP prove the capabilities of nanopatterning of biomolecules and nanoparticles on surfaces. Progressive development expands the capabilities of the NFP arranged as linear arrays to allow multiple-tip, multiple-ink patterning in parallel operation. Proof-of-concept experiments on the independent actuation of NFP are discussed in relation to the future integration on the arrays of NFP for massively parallel operation. Conceptual design of a two-dimensional NFP array and its operating scheme represent efforts to increase the throughput.
Additional study includes the development of an AFM tip made of diamond to address the tip wear caused by the contact-mode scanning probe techniques. A diamond probe monolithically integrated with a tip is microfabricated using a molding technique. A series of tests demonstrate the advantages of the developed probe such as wear resistance, molecular writing, electrical conductivity, and robustness. Future integration with NFP tips to allow an extended life-cycle is also discussed.
The NFP proves to be a bottom-up nanofabrication tool with the capabilities of high-resolution writing and microfluidic continuous feeding. The device extends to parallel arrays for multiple-tip, multiple-ink patterning. Such evolution envisions NFP as a high-throughput production tool for nano and biosystems.