Fabrication of microchannel arrays in borophosphosilicate glass

Abstract

Two-dimensional arrays of embedded channels with cross-sectional diameters of 1-3 m were fabricated in silica-on-silicon thin film structures. The channel arrays were fabricated using void-forming borophosphosilcate glass (BPSG) deposited by plasma-enhanced chemical vapor deposition (PECVD) over templates patterned and etched using standard photolithographic methods and reactive ion etching. The size and shape of the channels could be controlled by adjusting the depth, width, and spacing of the template ridges, the dopant levels in the BPSG, and the annealing conditions. Optimization of the channel fabrication process through detailed investigation of the process variables is presented. Potential applications in photonics, sensors, and microfluidics are discussed.

Photonic-Fluidic Integrated Microstructures for Sensor and Photonic Device Applications

“…We have previously demonstrated the controlled fabrication of embedded microchannels in silica glass layers [10]. In this paper we demonstrate more complex photonic-fluidic microstructures based on these microchannels.…”

“…The formation of microchannels in borophosphosilicate glass (BPSG) layers has been investigated in our laboratory and reported previously [10,11]. Briefly, doped silica layers are deposited by PECVD on a silicon wafer; adjusting the levels of B, P, and/or Ge dopants tightly controls the thermal, mechanical and optical properties of individual layers.…”

Microchannel Arrays in Borophosphosilicate Glass for Photonic Device and Optical Sensor Applications

“…A detailed description of the fabrication processes is presented elsewhere [4]. A detailed description of the fabrication processes is presented elsewhere [4].…”

Chemistry in nanochannel confinement

“…Both methods lead to nanochannels that have their smallest dimension perpendicular to the substrate (i.e., running parallel to the substrate surface); however, by combining them with deep-UV photolithography, laser interference lithography, or nanoimprint lithography (NIL) [69,70], it also becomes possible to control the lateral dimension (i.e., the dimension parallel to the substrate surface) down to several tens of nanometers. Alternative methods of achieving nano dimensions in the lateral direction without sophisticated lithography make use of shadowing effects at step edges [71,72], the special structures that arise after stiction of a surface-machined cantilever [72], or of nonuniform film step coverage in deep trenches, followed by an annealing step that leads to reflow of the film material and shrinkage of the channel [73]. In these methods, the limitations on dimensional control derive from either the lithographic definition, the control over the thin film thickness (and its uniformity), the control over the etching depth (and its uniformity), or the surface roughness (which is usually below 0.5 nm on average when polished silicon or glass substrates are used).…”