Design of a 1 DOF MEMS motion stage for a parallel plane geometry rheometer

Abstract

Rotational rheometers are used to measure paste properties, but the test would take too long to be useful for quality control (QC) on the job site. In this paper, a new type of rheometer is proposed based on a one degree of freedom (DOF) micro-electro-mechanical systems (MEMS)-based motion stage. Preliminary data will be presented to show the capability of the system to measure the viscoelastic properties of a paste. The parallel plate geometry rheometer consists of two plates, which move relative to each other to apply a strain to the material to be tested. From the stress measured and the strain applied, the rheological characteristics of the material can be calculated. The new device consists of an electrothermal actuator and a motion plate. For the rheological measurements, the device is designed to generate the shear stress up to 60 Pa and maintain its stiffness to less than 44 N/m. With these features, the device uses a square plate of 1.5 mm x 1.5 mm to provide enough area for a few micro-liter level volumes. The motion of the square plate is monitored by a capacitive sensor at the end of the oscillating plate which has a resolution of 1.06 μm. When a reference cementitious paste, Standard Reference Material (SRM)-2492, is placed between the oscillating plate of the presented motion stage and a fixed plate, the reduction in the displacement of the oscillating plate is monitored showing that the presented motion stage is reasonably designed to detect the response of the reference cementitious paste.

A portable picometer reference actuator with 100 µm range, picometer resolution, subnanometer accuracy and submicroradian tip-tilt error for the characterization of measuring instruments at the nanoscale

“…Dimensional measurements promote innovation and competitiveness in manufacturing through measurement science, services, and technical contributions to standards stimulating the realization of high-precision measurement techniques at the nanoscale. Dimensional measurements play a crucial role in almost every aspect of modern life, ranging over medical devices [1], optical sensors [2], microelectromechanical systems [3][4][5], integrated circuit technology [6], ICT, and cutting-edge nanotechnologies [7] where precise dimensions and standardization are paramount in product specification and quality certification. In particular, for dimensional metrology in semiconductor manufacturing processes [8,9], laser interferometers are the unsurpassed standard for both pattern scaling on photomasks and for their alignment and precision overlap on multi-layered wafers densely populated by transistors whose transversal dimension can already reach the noticeable size of only 1 nm [10][11][12].…”