A low-temperature wafer bonding technique using patternable materials

Abstract

In this paper we present a silicon wafer bonding technique for 3D microstructures using MEMS process technology. Photo-definable material with patternable characteristics served as the bonding layer between the silicon wafers. A bonding process was developed and several types of photo-definable material were tested for bonding strength and pattern spatial resolution. The results indicated that SU-8 is the best material with a bonding strength of up to 213 kg cm−2 (20.6 MPa), and a spatial resolution of 10 μm, at a layer thickness of up to 100 μm. The low-temperature bonding technique that is presented is particularly suitable for microstructure and microelectronics integration involved in MEMS packaging.

Electrolysis-based diaphragm actuators

“…Finally we used thermal bonding to bond the two chips firmly and seal the chambers around the side wall, leaving only the conduction channels and electrolyte injection channels open. We tried two kinds of bonding method using either parylene or photoresist (Pan et al 2002). Based on the experimental data for diaphragm deflection, calculation shows that the photoresist bonding can hold under pressures as high as 500 psi (3.45 × 10 6 Pa).…”

Low Temperature Wafer-Level Metal Thermo-Compression Bonding Technology for 3D Integration

“…Since a layer of polymer or inorganic adhesive is always spun before bonding, it is very suitable for non-uniform surfaces and for bonding at low temperature. Benzocyclobutene (BCB) and SU-8 are the most common materials used in 3D integration, since high bonding strength can be easily achieved with these two polymer materials (Niklaus et al, 2001;Pan et al, 2002).…”

Fabrication of miniaturized fluidic devices using SU-8 based lithography and low temperature wafer bonding

“…It is reported that a bonding strenght of ∼20 MPa can be achieved if SU-8 is used as intermediate layer for adhesive wafer bonding [8]. Wafer bonding with SU-8 can be performed simply by applying contact force and heat to a stack of wafers which carry SU-8 structures [9].…”