Micro-Fluidic MEMS for Micro-Particle Filtration

Micro-Fluidic MEMS for Micro-Particle Filtration

Li, S.J.

Sarro, P.M. (mentor)
Shen, C. (mentor)

Electrical Engineering, Mathematics and Computer Science

ECTM

MSc Micro-electronics

2011-08-30

Recently there has been an onset of fluidic filters fabricated using micro electro-mechanical systems (MEMS) technology. These filters, compared to conventional ones, are more accurate and precise due to the highly sophisticated techniques that are used to define and implement the separation mechanism. In order to contribute to this new field of research, a project on micro- and nanoparticle filtration was started in the MEMS group of Delft Institute of Microsystems and Nanoelectronics. This project had grown to produce two MEMS filter designs prior to the beginning of this graduation thesis. This thesis study seeks to identify and analyze reoccurring issues in the two MEMS filter designs and from those results, realize a new design that is superior in the aspects of performance, robustness and durability. The first MEMS filter design proves that it is possible to create vertical membrane filtration devices using MEMS technology and seal these with dry film photo-resist. However, the first design suffers from a high flow resistance that cannot be dealt with effectively, without relying on a more area efficient design. The second MEMS filter design is meant to outperform the first design in the aspect of flow resistance. The second design is a promising concept, but does not reach its full potential. Critical issues from a number of sources degrade and limit its performance to such a degree that it is close to dysfunctional. A redesign is necessary to fully exploit the advantageous aspects of the second design. A third MEMS filter design was developed based on the knowledge and experience gained from the preceding designs. This third design aims to incorporate the advantages of both the first and second designs while avoiding their disadvantages. Although the third design does address and solve the problems encountered in preceding designs, the development of this design resulted in new issues that are yet to be addressed. However, despite the addition of new issues, fully functional devices for fluidic experiments could still be fabricated. A series of fluidic experiments were performed to verify the functionality and performance of the fabricated designs. The basic filter function was hereby confirmed for all devices. Moreover, pressure and flow rate experiments were carried out to quantify the performance parameters of the filter devices. From these results, devices from the third design were found to have the best pressure and flow rate performance. A qualitative comparison was made between the three different filter designs. This comparison considers both the structural aspects of the designs and the data gained from the fluidic experiments. Based on the comparison, the conclusion is made that the problem initially defined for this thesis has been properly addresses by the third design. Although further optimization is still possible, the third design has proven to be the best amongst the three MEMS filter designs.

MEMS
silicon micromachining
particle separation

http://resolver.tudelft.nl/uuid:727a48af-06e8-4d58-8a02-9ffde0d1624e

2011-09-13

Student theses

master thesis

(c) 2011 Li, S.J.