High-Efficient Chip to Wafer Self-Alignment and Bonding Applicable to MEMS-IC Flexible Integration

Abstract

In this paper, a flexible approach for chip to wafer high-accurate alignment and bonding is developed using a selfassembled monolayer (SAM). In this approach, a hydrophobic SAM, FDTS (CF 3 (CF 2 ) 7 (CH 2 ) 2 SiCl 3 ), is successfully patterned by lift-off process on an oxidized silicon wafer to define the binding-sites. A certain volume of H 2 O (µ/mm 2 ) is dropped and then spread on the non-coated hydrophilic SiO 2 bindingsites for self-alignment of various microelectromechanical systems (MEMS) and IC chips by capillary force of H 2 O. Our results demonstrate that reasonably high alignment speed (in milliseconds) and excellent alignment accuracy (≤1 µm) are achieved when the difference in the measured contact angle between hydrophobic FDTS and hydrophilic binding-sites is >70°. It is also found that the hydrophilic frame at the edge of each binding-site is effective in achieving successful self-alignment, while a super fine pattern at the center of the binding-site can be used to control the bonding strength. The effects of the Au/Cr thin film pattern on self-alignment are studied and discussed in this paper to enable the application of the above approach in various MEMS-IC integration processes, especially for low-cost mass production of wireless sensor nodes.Index Terms-FDTS, large scale integration, microelectromechanical system (MEMS), self-alignment, wireless sensor node.

Multi-Physical Models of Bending Characteristics on the Double-Clamped Beam Switch for Flexible Electronic Devices Application

“…The flexible electronic devices that manufacture electronic devices of organic or inorganic materials on a stretchable or bendable substrate are widely used in numerous fields including flexible communications [ 1 , 2 , 3 , 4 ], flexible sensors [ 5 , 6 , 7 , 8 ], flexible energy conversion [ 9 , 10 ], due to their advantages of miniaturization, bendability, high ductility, and low manufacturing cost. Flexible RF MEMS (Radio Frequency Micro-Electro-Mechanical Systems) devices [ 11 , 12 , 13 , 14 , 15 , 16 ] play an irreplaceable role in flexible communications and sensors for the excellent microwave performance and ultralow-power consumption.…”

“…y k ¢ is the revised y-directio astic constant of the beam. The additional elastic constant of the spring-like double-clamped bea der bending conditions can be calculated by substituting the revised S ¢ into Equation(4). O e other hand, when the substrate is bending, the gap between the spring-like double-clamped bea d driving electrodes is decreased and the revised gap can be calculated b where t is the thickness of the signal line, a is th stance relative to the center of the signal line.…”

Contribution to liquid lens technology

“…Recently the interest on using superhydrophobic layers in a variety of industrial applications, such as anticorrosive protective coatings, microfluidics (microchannels and reactors, lab-ona-chip devices and biomedical devices) [153][154][155] , self-assembly of particles [156,157] and self-cleaning surfaces, such as window glasses [158], paints, and fabrics, green engineering [159], marine fouling [160], anti-icing surface [161,162], drag reducing surfaces [163],…”

“…By reducing significantly the thickness of the hydrophobic layer combined with the use of ultrathin dielectric later with high dielectric permittivity, should lead to an increase of the initial contact angle value and to achieve a large change of the contact angle even at modest voltages. FDTS has a long chain and forms nanometer scale clouds leading to ultrathin (nanometer scale) superhydrophobic layers which have great potential to be used as alternative to Teflon [157]. In this chapter we describe experiments aimed to (a) assess the superhydrophobicity of FDTS layers in structures suitable for EWOD, that is to say on top of ITO transparent electrodes covered by a thin dielectric layer (alumina in this Chapter following the experience gained in previous chapters), (b) to check the recovery of the contact angle after electrowetting and (c) to examine the integrity of the FDTS layer in EWOD operating conditions for electrowetting applications.…”